title: Radiocarbon dating

text: The above calculations make several assumptions, such as that the level of in the atmosphere has remained constant over time. In fact, the level of in the atmosphere has varied significantly and as a result, the values provided by the equation above have to be corrected by using data from other sources. This is done by calibration curves (discussed below), which convert a measurement of in a sample into an estimated calendar age. The calculations involve several steps and include an intermediate value called the "radiocarbon age", which is the age in "radiocarbon years" of the sample: an age quoted in radiocarbon years means that no calibration curve has been used − the calculations for radiocarbon years assume that the atmospheric / ratio has not changed over time.


title: Radiocarbon dating

text: Calculating radiocarbon ages also requires the value of the half-life for . In Libby's 1949 paper he used a value of 5720 ± 47 years, based on research by Engelkemeir et al. This was remarkably close to the modern value, but shortly afterwards the accepted value was revised to 5568 ± 30 years, and this value was in use for more than a decade. It was revised again in the early 1960s to 5,730 ± 40 years, which meant that many calculated dates in papers published prior to this were incorrect (the error in the half-life is about 3%). For consistency with these early papers, it was agreed at the 1962 Radiocarbon Conference in Cambridge (UK) to use the "Libby half-life" of 5568 years. Radiocarbon ages are still calculated using this half-life, and are known as "Conventional Radiocarbon Age". Since the calibration curve (IntCal) also reports past atmospheric concentration using this conventional age, any conventional ages calibrated against the IntCal curve will produce a correct calibrated age. When a date is quoted, the reader should be aware that if it is an uncalibrated date (a term used for dates given in radiocarbon years) it may differ substantially from the best estimate of the actual calendar date, both because it uses the wrong value for the half-life of , and because no correction (calibration) has been applied for the historical variation of in the atmosphere over time.


title: Radiocarbon dating

text: Carbon is distributed throughout the atmosphere, the biosphere, and the oceans; these are referred to collectively as the carbon exchange reservoir, and each component is also referred to individually as a carbon exchange reservoir. The different elements of the carbon exchange reservoir vary in how much carbon they store, and in how long it takes for the generated by cosmic rays to fully mix with them. This affects the ratio of to in the different reservoirs, and hence the radiocarbon ages of samples that originated in each reservoir. The atmosphere, which is where is generated, contains about 1.9% of the total carbon in the reservoirs, and the it contains mixes in less than seven years. The ratio of to in the atmosphere is taken as the baseline for the other reservoirs: if another reservoir has a lower ratio of to , it indicates that the carbon is older and hence that either some of the has decayed, or the reservoir is receiving carbon that is not at the atmospheric baseline. The ocean surface is an example: it contains 2.4% of the carbon in the exchange reservoir, but there is only about 95% as much as would be expected if the ratio were the same as in the atmosphere. The time it takes for carbon from the atmosphere to mix with the surface ocean is only a few years, but the surface waters also receive water from the deep ocean, which has more than 90% of the carbon in the reservoir. Water in the deep ocean takes about 1,000 years to circulate back through surface waters, and so the surface waters contain a combination of older water, with depleted , and water recently at the surface, with in equilibrium with the atmosphere.


title: Radiocarbon dating

text: Creatures living at the ocean surface have the same ratios as the water they live in, and as a result of the reduced / ratio, the radiocarbon age of marine life is typically about 400 years. Organisms on land are in closer equilibrium with the atmosphere and have the same / ratio as the atmosphere. These organisms contain about 1.3% of the carbon in the reservoir; sea organisms have a mass of less than 1% of those on land and are not shown in the diagram. Accumulated dead organic matter, of both plants and animals, exceeds the mass of the biosphere by a factor of nearly 3, and since this matter is no longer exchanging carbon with its environment, it has a / ratio lower than that of the biosphere.


title: Radiocarbon dating

text: The variation in the / ratio in different parts of the carbon exchange reservoir means that a straightforward calculation of the age of a sample based on the amount of it contains will often give an incorrect result. There are several other possible sources of error that need to be considered. The errors are of four general types:


title: Radiocarbon dating

text: In the early years of using the technique, it was understood that it depended on the atmospheric / ratio having remained the same over the preceding few thousand years. To verify the accuracy of the method, several artefacts that were datable by other techniques were tested; the results of the testing were in reasonable agreement with the true ages of the objects. Over time, however, discrepancies began to appear between the known chronology for the oldest Egyptian dynasties and the radiocarbon dates of Egyptian artefacts. Neither the pre-existing Egyptian chronology nor the new radiocarbon dating method could be assumed to be accurate, but a third possibility was that the / ratio had changed over time. The question was resolved by the study of tree rings: comparison of overlapping series of tree rings allowed the construction of a continuous sequence of tree-ring data that spanned 8,000 years. (Since that time the tree-ring data series has been extended to 13,900 years.) In the 1960s, Hans Suess was able to use the tree-ring sequence to show that the dates derived from radiocarbon were consistent with the dates assigned by Egyptologists. This was possible because although annual plants, such as corn, have a / ratio that reflects the atmospheric ratio at the time they were growing, trees only add material to their outermost tree ring in any given year, while the inner tree rings don't get their replenished and instead start losing through decay. Hence each ring preserves a record of the atmospheric / ratio of the year it grew in. Carbon-dating the wood from the tree rings themselves provides the check needed on the atmospheric / ratio: with a sample of known date, and a measurement of the value of "N" (the number of atoms of remaining in the sample), the carbon-dating equation allows the calculation of "N" – the number of atoms of in the sample at the time the tree ring was formed – and hence the / ratio in the atmosphere at that time. Equipped with the results of carbon-dating the tree rings, it became possible to construct calibration curves designed to correct the errors caused by the variation over time in the / ratio. These curves are described in more detail below.


title: Radiocarbon dating

text: Coal and oil began to be burned in large quantities during the 19th century. Both are sufficiently old that they contain little or no detectable and, as a result, the released substantially diluted the atmospheric / ratio. Dating an object from the early 20th century hence gives an apparent date older than the true date. For the same reason, concentrations in the neighbourhood of large cities are lower than the atmospheric average. This fossil fuel effect (also known as the Suess effect, after Hans Suess, who first reported it in 1955) would only amount to a reduction of 0.2% in activity if the additional carbon from fossil fuels were distributed throughout the carbon exchange reservoir, but because of the long delay in mixing with the deep ocean, the actual effect is a 3% reduction.


title: Radiocarbon dating

text: A much larger effect comes from above-ground nuclear testing, which released large numbers of neutrons into the atmosphere, resulting in the creation of . From about 1950 until 1963, when atmospheric nuclear testing was banned, it is estimated that several tonnes of were created. If all this extra had immediately been spread across the entire carbon exchange reservoir, it would have led to an increase in the / ratio of only a few per cent, but the immediate effect was to almost double the amount of in the atmosphere, with the peak level occurring in 1964 for the northern hemisphere, and in 1966 for the southern hemisphere. The level has since dropped, as this bomb pulse or "bomb carbon" (as it is sometimes called) percolates into the rest of the reservoir.


title: Radiocarbon dating

text: Photosynthesis is the primary process by which carbon moves from the atmosphere into living things. In photosynthetic pathways is absorbed slightly more easily than , which in turn is more easily absorbed than . The differential uptake of the three carbon isotopes leads to / and / ratios in plants that differ from the ratios in the atmosphere. This effect is known as isotopic fractionation.


title: Radiocarbon dating

text: To determine the degree of fractionation that takes place in a given plant, the amounts of both and isotopes are measured, and the resulting / ratio is then compared to a standard ratio known as PDB. The / ratio is used instead of / because the former is much easier to measure, and the latter can be easily derived: the depletion of relative to is proportional to the difference in the atomic masses of the two isotopes, so the depletion for is twice the depletion of . The fractionation of , known as , is calculated as follows:


title: Radiocarbon dating

text: where the ‰ sign indicates parts per thousand. Because the PDB standard contains an unusually high proportion of , most measured values are negative.


title: Radiocarbon dating

text: For marine organisms, the details of the photosynthesis reactions are less well understood, and the values for marine photosynthetic organisms are dependent on temperature. At higher temperatures, has poor solubility in water, which means there is less available for the photosynthetic reactions. Under these conditions, fractionation is reduced, and at temperatures above 14 °C the values are correspondingly higher, while at lower temperatures, becomes more soluble and hence more available to marine organisms. The value for animals depends on their diet. An animal that eats food with high values will have a higher than one that eats food with lower values. The animal's own biochemical processes can also impact the results: for example, both bone minerals and bone collagen typically have a higher concentration of than is found in the animal's diet, though for different biochemical reasons. The enrichment of bone also implies that excreted material is depleted in relative to the diet.


title: Radiocarbon dating

text: Since makes up about 1% of the carbon in a sample, the / ratio can be accurately measured by mass spectrometry. Typical values of have been found by experiment for many plants, as well as for different parts of animals such as bone collagen, but when dating a given sample it is better to determine the value for that sample directly than to rely on the published values.


title: Radiocarbon dating

text: The carbon exchange between atmospheric and carbonate at the ocean surface is also subject to fractionation, with in the atmosphere more likely than to dissolve in the ocean. The result is an overall increase in the / ratio in the ocean of 1.5%, relative to the / ratio in the atmosphere. This increase in concentration almost exactly cancels out the decrease caused by the upwelling of water (containing old, and hence -depleted, carbon) from the deep ocean, so that direct measurements of radiation are similar to measurements for the rest of the biosphere. Correcting for isotopic fractionation, as is done for all radiocarbon dates to allow comparison between results from different parts of the biosphere, gives an apparent age of about 400 years for ocean surface water.


title: Radiocarbon dating

text: Libby's original exchange reservoir hypothesis assumed that the / ratio in the exchange reservoir is constant all over the world, but it has since been discovered that there are several causes of variation in the ratio across the reservoir.


title: Radiocarbon dating

text: The in the atmosphere transfers to the ocean by dissolving in the surface water as carbonate and bicarbonate ions; at the same time the carbonate ions in the water are returning to the air as . This exchange process brings from the atmosphere into the surface waters of the ocean, but the thus introduced takes a long time to percolate through the entire volume of the ocean. The deepest parts of the ocean mix very slowly with the surface waters, and the mixing is uneven. The main mechanism that brings deep water to the surface is upwelling, which is more common in regions closer to the equator. Upwelling is also influenced by factors such as the topography of the local ocean bottom and coastlines, the climate, and wind patterns. Overall, the mixing of deep and surface waters takes far longer than the mixing of atmospheric with the surface waters, and as a result water from some deep ocean areas has an apparent radiocarbon age of several thousand years. Upwelling mixes this "old" water with the surface water, giving the surface water an apparent age of about several hundred years (after correcting for fractionation). This effect is not uniform – the average effect is about 400 years, but there are local deviations of several hundred years for areas that are geographically close to each other. These deviations can be accounted for in calibration, and users of software such as CALIB can provide as an input the appropriate correction for the location of their samples. The effect also applies to marine organisms such as shells, and marine mammals such as whales and seals, which have radiocarbon ages that appear to be hundreds of years old.


title: Radiocarbon dating

text: The northern and southern hemispheres have atmospheric circulation systems that are sufficiently independent of each other that there is a noticeable time lag in mixing between the two. The atmospheric / ratio is lower in the southern hemisphere, with an apparent additional age of about 40 years for radiocarbon results from the south as compared to the north. This is because the greater surface area of ocean in the southern hemisphere means that there is more carbon exchanged between the ocean and the atmosphere than in the north. Since the surface ocean is depleted in because of the marine effect, is removed from the southern atmosphere more quickly than in the north. The effect is strengthened by strong upwelling around Antarctica.


title: Radiocarbon dating

text: If the carbon in freshwater is partly acquired from aged carbon, such as rocks, then the result will be a reduction in the / ratio in the water. For example, rivers that pass over limestone, which is mostly composed of calcium carbonate, will acquire carbonate ions. Similarly, groundwater can contain carbon derived from the rocks through which it has passed. These rocks are usually so old that they no longer contain any measurable , so this carbon lowers the / ratio of the water it enters, which can lead to apparent ages of thousands of years for both the affected water and the plants and freshwater organisms that live in it. This is known as the hard water effect because it is often associated with calcium ions, which are characteristic of hard water; other sources of carbon such as humus can produce similar results, and can also reduce the apparent age if they are of more recent origin than the sample. The effect varies greatly and there is no general offset that can be applied; additional research is usually needed to determine the size of the offset, for example by comparing the radiocarbon age of deposited freshwater shells with associated organic material.


title: Radiocarbon dating

text: Volcanic eruptions eject large amounts of carbon into the air. The carbon is of geological origin and has no detectable , so the / ratio in the vicinity of the volcano is depressed relative to surrounding areas. Dormant volcanoes can also emit aged carbon. Plants that photosynthesize this carbon also have lower / ratios: for example, plants in the neighbourhood of the Furnas caldera in the Azores were found to have apparent ages that ranged from 250 years to 3320 years.


title: Radiocarbon dating

text: Any addition of carbon to a sample of a different age will cause the measured date to be inaccurate. Contamination with modern carbon causes a sample to appear to be younger than it really is: the effect is greater for older samples. If a sample that is 17,000 years old is contaminated so that 1% of the sample is modern carbon, it will appear to be 600 years younger; for a sample that is 34,000 years old, the same amount of contamination would cause an error of 4,000 years. Contamination with old carbon, with no remaining , causes an error in the other direction independent of age – a sample contaminated with 1% old carbon will appear to be about 80 years older than it truly is, regardless of the date of the sample.


title: Radiocarbon dating

text: Samples for dating need to be converted into a form suitable for measuring the content; this can mean conversion to gaseous, liquid, or solid form, depending on the measurement technique to be used. Before this can be done, the sample must be treated to remove any contamination and any unwanted constituents. This includes removing visible contaminants, such as rootlets that may have penetrated the sample since its burial. Alkali and acid washes can be used to remove humic acid and carbonate contamination, but care has to be taken to avoid removing the part of the sample that contains the carbon to be tested.


title: Radiocarbon dating

text: Particularly for older samples, it may be useful to enrich the amount of in the sample before testing. This can be done with a thermal diffusion column. The process takes about a month and requires a sample about ten times as large as would be needed otherwise, but it allows more precise measurement of the / ratio in old material and extends the maximum age that can be reliably reported.


title: Radiocarbon dating

text: Once contamination has been removed, samples must be converted to a form suitable for the measuring technology to be used. Where gas is required, is widely used. For samples to be used in liquid scintillation counters, the carbon must be in liquid form; the sample is typically converted to benzene. For accelerator mass spectrometry, solid graphite targets are the most common, although gaseous can also be used.


title: Radiocarbon dating

text: The quantity of material needed for testing depends on the sample type and the technology being used. There are two types of testing technology: detectors that record radioactivity, known as beta counters, and accelerator mass spectrometers. For beta counters, a sample weighing at least is typically required. Accelerator mass spectrometry is much more sensitive, and samples containing as little as 0.5 milligrams of carbon can be used.


title: Radiocarbon dating

text: For decades after Libby performed the first radiocarbon dating experiments, the only way to measure the in a sample was to detect the radioactive decay of individual carbon atoms. In this approach, what is measured is the activity, in number of decay events per unit mass per time period, of the sample. This method is also known as "beta counting", because it is the beta particles emitted by the decaying atoms that are detected. In the late 1970s an alternative approach became available: directly counting the number of and atoms in a given sample, via accelerator mass spectrometry, usually referred to as AMS. AMS counts the / ratio directly, instead of the activity of the sample, but measurements of activity and / ratio can be converted into each other exactly. For some time, beta counting methods were more accurate than AMS, but AMS is now more accurate and has become the method of choice for radiocarbon measurements. In addition to improved accuracy, AMS has two further significant advantages over beta counting: it can perform accurate testing on samples much too small for beta counting, and it is much faster – an accuracy of 1% can be achieved in minutes with AMS, which is far quicker than would be achievable with the older technology.


title: Radiocarbon dating

text: Libby's first detector was a Geiger counter of his own design. He converted the carbon in his sample to lamp black (soot) and coated the inner surface of a cylinder with it. This cylinder was inserted into the counter in such a way that the counting wire was inside the sample cylinder, in order that there should be no material between the sample and the wire. Any interposing material would have interfered with the detection of radioactivity, since the beta particles emitted by decaying are so weak that half are stopped by a 0.01 mm thickness of aluminium.


title: Radiocarbon dating

text: Libby's method was soon superseded by gas proportional counters, which were less affected by bomb carbon (the additional created by nuclear weapons testing). These counters record bursts of ionization caused by the beta particles emitted by the decaying atoms; the bursts are proportional to the energy of the particle, so other sources of ionization, such as background radiation, can be identified and ignored. The counters are surrounded by lead or steel shielding, to eliminate background radiation and to reduce the incidence of cosmic rays. In addition, anticoincidence detectors are used; these record events outside the counter and any event recorded simultaneously both inside and outside the counter is regarded as an extraneous event and ignored.


title: Radiocarbon dating

text: The other common technology used for measuring activity is liquid scintillation counting, which was invented in 1950, but which had to wait until the early 1960s, when efficient methods of benzene synthesis were developed, to become competitive with gas counting; after 1970 liquid counters became the more common technology choice for newly constructed dating laboratories. The counters work by detecting flashes of light caused by the beta particles emitted by as they interact with a fluorescing agent added to the benzene. Like gas counters, liquid scintillation counters require shielding and anticoincidence counters.


title: Radiocarbon dating

text: For both the gas proportional counter and liquid scintillation counter, what is measured is the number of beta particles detected in a given time period. Since the mass of the sample is known, this can be converted to a standard measure of activity in units of either counts per minute per gram of carbon (cpm/g C), or becquerels per kg (Bq/kg C, in SI units). Each measuring device is also used to measure the activity of a blank sample – a sample prepared from carbon old enough to have no activity. This provides a value for the background radiation, which must be subtracted from the measured activity of the sample being dated to get the activity attributable solely to that sample's . In addition, a sample with a standard activity is measured, to provide a baseline for comparison.


title: Radiocarbon dating

text: AMS counts the atoms of and in a given sample, determining the / ratio directly. The sample, often in the form of graphite, is made to emit C ions (carbon atoms with a single negative charge), which are injected into an accelerator. The ions are accelerated and passed through a stripper, which removes several electrons so that the ions emerge with a positive charge. The ions, which may have from 1 to 4 positive charges (C to C), depending on the accelerator design, are then passed through a magnet that curves their path; the heavier ions are curved less than the lighter ones, so the different isotopes emerge as separate streams of ions. A particle detector then records the number of ions detected in the stream, but since the volume of (and , needed for calibration) is too great for individual ion detection, counts are determined by measuring the electric current created in a Faraday cup. The large positive charge induced by the stripper forces molecules such as , which has a weight close enough to to interfere with the measurements, to dissociate, so they are not detected. Most AMS machines also measure the sample's , for use in calculating the sample's radiocarbon age. The use of AMS, as opposed to simpler forms of mass spectrometry, is necessary because of the need to distinguish the carbon isotopes from other atoms or molecules that are very close in mass, such as and . As with beta counting, both blank samples and standard samples are used. Two different kinds of blank may be measured: a sample of dead carbon that has undergone no chemical processing, to detect any machine background, and a sample known as a process blank made from dead carbon that is processed into target material in exactly the same way as the sample which is being dated. Any signal from the machine background blank is likely to be caused either by beams of ions that have not followed the expected path inside the detector or by carbon hydrides such as or . A signal from the process blank measures the amount of contamination introduced during the preparation of the sample. These measurements are used in the subsequent calculation of the age of the sample.


title: Radiocarbon dating

text: The calculations to be performed on the measurements taken depend on the technology used, since beta counters measure the sample's radioactivity whereas AMS determines the ratio of the three different carbon isotopes in the sample.


title: Radiocarbon dating

text: To determine the age of a sample whose activity has been measured by beta counting, the ratio of its activity to the activity of the standard must be found. To determine this, a blank sample (of old, or dead, carbon) is measured, and a sample of known activity is measured. The additional samples allow errors such as background radiation and systematic errors in the laboratory setup to be detected and corrected for. The most common standard sample material is oxalic acid, such as the HOxII standard, 1,000 lb of which was prepared by the National Institute of Standards and Technology (NIST) in 1977 from French beet harvests.


title: Radiocarbon dating

text: The results from AMS testing are in the form of ratios of , , and , which are used to calculate Fm, the "fraction modern". This is defined as the ratio between the / ratio in the sample and the / ratio in modern carbon, which is in turn defined as the / ratio that would have been measured in 1950 had there been no fossil fuel effect.


title: Radiocarbon dating

text: Both beta counting and AMS results have to be corrected for fractionation. This is necessary because different materials of the same age, which because of fractionation have naturally different / ratios, will appear to be of different ages because the / ratio is taken as the indicator of age. To avoid this, all radiocarbon measurements are converted to the measurement that would have been seen had the sample been made of wood, which has a known δ value of −25‰.


title: Radiocarbon dating

text: The calculation uses 8,033 years, the mean-life derived from Libby's half-life of 5,568 years, not 8,267 years, the mean-life derived from the more accurate modern value of 5,730 years. Libby's value for the half-life is used to maintain consistency with early radiocarbon testing results; calibration curves include a correction for this, so the accuracy of final reported calendar ages is assured.


title: Radiocarbon dating

text: The reliability of the results can be improved by lengthening the testing time. For example, if counting beta decays for 250 minutes is enough to give an error of ± 80 years, with 68% confidence, then doubling the counting time to 500 minutes will allow a sample with only half as much to be measured with the same error term of 80 years.


title: Radiocarbon dating

text: Radiocarbon dating is generally limited to dating samples no more than 50,000 years old, as samples older than that have insufficient to be measurable. Older dates have been obtained by using special sample preparation techniques, large samples, and very long measurement times. These techniques can allow measurement of dates up to 60,000 and in some cases up to 75,000 years before the present.


title: Radiocarbon dating

text: Radiocarbon dates are generally presented with a range of one standard deviation (usually represented by the Greek letter sigma as 1σ) on either side of the mean. However, a date range of 1σ represents only a 68% confidence level, so the true age of the object being measured may lie outside the range of dates quoted. This was demonstrated in 1970 by an experiment run by the British Museum radiocarbon laboratory, in which weekly measurements were taken on the same sample for six months. The results varied widely (though consistently with a normal distribution of errors in the measurements), and included multiple date ranges (of 1σ confidence) that did not overlap with each other. The measurements included one with a range from about 4250 to about 4390 years ago, and another with a range from about 4520 to about 4690.


title: Radiocarbon dating

text: Errors in procedure can also lead to errors in the results. If 1% of the benzene in a modern reference sample accidentally evaporates, scintillation counting will give a radiocarbon age that is too young by about 80 years.


title: Radiocarbon dating

text: The calculations given above produce dates in radiocarbon years: i.e. dates that represent the age the sample would be if the / ratio had been constant historically. Although Libby had pointed out as early as 1955 the possibility that this assumption was incorrect, it was not until discrepancies began to accumulate between measured ages and known historical dates for artefacts that it became clear that a correction would need to be applied to radiocarbon ages to obtain calendar dates.


title: Radiocarbon dating

text: To produce a curve that can be used to relate calendar years to radiocarbon years, a sequence of securely dated samples is needed which can be tested to determine their radiocarbon age. The study of tree rings led to the first such sequence: individual pieces of wood show characteristic sequences of rings that vary in thickness because of environmental factors such as the amount of rainfall in a given year. These factors affect all trees in an area, so examining tree-ring sequences from old wood allows the identification of overlapping sequences. In this way, an uninterrupted sequence of tree rings can be extended far into the past. The first such published sequence, based on bristlecone pine tree rings, was created by Wesley Ferguson. Hans Suess used this data to publish the first calibration curve for radiocarbon dating in 1967. The curve showed two types of variation from the straight line: a long term fluctuation with a period of about 9,000 years, and a shorter-term variation, often referred to as "wiggles", with a period of decades. Suess said he drew the line showing the wiggles by "cosmic "schwung"", by which he meant that the variations were caused by extraterrestrial forces. It was unclear for some time whether the wiggles were real or not, but they are now well-established. These short term fluctuations in the calibration curve are now known as de Vries effects, after Hessel de Vries.


title: Radiocarbon dating

text: A calibration curve is used by taking the radiocarbon date reported by a laboratory and reading across from that date on the vertical axis of the graph. The point where this horizontal line intersects the curve will give the calendar age of the sample on the horizontal axis. This is the reverse of the way the curve is constructed: a point on the graph is derived from a sample of known age, such as a tree ring; when it is tested, the resulting radiocarbon age gives a data point for the graph.


title: Radiocarbon dating

text: Over the next thirty years many calibration curves were published using a variety of methods and statistical approaches. These were superseded by the IntCal series of curves, beginning with IntCal98, published in 1998, and updated in 2004, 2009, 2013, and 2020. The improvements to these curves are based on new data gathered from tree rings, varves, coral, plant macrofossils, speleothems, and foraminifera. The IntCal20 data includes separate curves for the northern and southern hemispheres, as they differ systematically because of the hemisphere effect. The southern curve (SHCAL20) is based on independent data where possible and derived from the northern curve by adding the average offset for the southern hemisphere where no direct data was available. There is also a separate marine calibration curve, MARINE20. For a set of samples forming a sequence with a known separation in time, these samples form a subset of the calibration curve. The sequence can be compared to the calibration curve and the best match to the sequence established. This "wiggle-matching" technique can lead to more precise dating than is possible with individual radiocarbon dates. Wiggle-matching can be used in places where there is a plateau on the calibration curve, and hence can provide a much more accurate date than the intercept or probability methods are able to produce. The technique is not restricted to tree rings; for example, a stratified tephra sequence in New Zealand, believed to predate human colonization of the islands, has been dated to 1314 AD ± 12 years by wiggle-matching. The wiggles also mean that reading a date from a calibration curve can give more than one answer: this occurs when the curve wiggles up and down enough that the radiocarbon age intercepts the curve in more than one place, which may lead to a radiocarbon result being reported as two separate age ranges, corresponding to the two parts of the curve that the radiocarbon age intercepted.


title: Radiocarbon dating

text: Bayesian statistical techniques can be applied when there are several radiocarbon dates to be calibrated. For example, if a series of radiocarbon dates is taken from different levels in a stratigraphic sequence, Bayesian analysis can be used to evaluate dates which are outliers and can calculate improved probability distributions, based on the prior information that the sequence should be ordered in time. When Bayesian analysis was introduced, its use was limited by the need to use mainframe computers to perform the calculations, but the technique has since been implemented on programs available for personal computers, such as OxCal.


title: Radiocarbon dating

text: Several formats for citing radiocarbon results have been used since the first samples were dated. As of 2019, the standard format required by the journal "Radiocarbon" is as follows.


title: Radiocarbon dating

text: For example, the uncalibrated date "UtC-2020: 3510 ± 60 BP" indicates that the sample was tested by the Utrecht van der Graaff Laboratorium ("UtC"), where it has a sample number of "2020", and that the uncalibrated age is 3510 years before present, ± 60 years. Related forms are sometimes used: for example, "10 ka BP" means 10,000 radiocarbon years before present (i.e. 8,050 BC), and " yr BP" might be used to distinguish the uncalibrated date from a date derived from another dating method such as thermoluminescence.


title: Radiocarbon dating

text: Calibrated dates are frequently reported as "cal BP", "cal BC", or "cal AD", again with 'BP' referring to the year 1950 as the zero date. "Radiocarbon" gives two options for reporting calibrated dates. A common format is "cal ", where:


title: Radiocarbon dating

text: For example, "cal 1220–1281 AD (1σ)" means a calibrated date for which the true date lies between 1220 AD and 1281 AD, with a confidence level of '1 sigma', or approximately 68%. Calibrated dates can also be expressed as "BP" instead of using "BC" and "AD". The curve used to calibrate the results should be the latest available IntCal curve. Calibrated dates should also identify any programs, such as OxCal, used to perform the calibration. In addition, an article in "Radiocarbon" in 2014 about radiocarbon date reporting conventions recommends that information should be provided about sample treatment, including the sample material, pretreatment methods, and quality control measurements; that the citation to the software used for calibration should specify the version number and any options or models used; and that the calibrated date should be given with the associated probabilities for each range.


title: Radiocarbon dating

text: A key concept in interpreting radiocarbon dates is archaeological association: what is the true relationship between two or more objects at an archaeological site? It frequently happens that a sample for radiocarbon dating can be taken directly from the object of interest, but there are also many cases where this is not possible. Metal grave goods, for example, cannot be radiocarbon dated, but they may be found in a grave with a coffin, charcoal, or other material which can be assumed to have been deposited at the same time. In these cases, a date for the coffin or charcoal is indicative of the date of deposition of the grave goods, because of the direct functional relationship between the two. There are also cases where there is no functional relationship, but the association is reasonably strong: for example, a layer of charcoal in a rubbish pit provides a date which has a relationship to the rubbish pit.


title: Radiocarbon dating

text: Contamination is of particular concern when dating very old material obtained from archaeological excavations and great care is needed in the specimen selection and preparation. In 2014, Thomas Higham and co-workers suggested that many of the dates published for Neanderthal artifacts are too recent because of contamination by "young carbon".


title: Radiocarbon dating

text: As a tree grows, only the outermost tree ring exchanges carbon with its environment, so the age measured for a wood sample depends on where the sample is taken from. This means that radiocarbon dates on wood samples can be older than the date at which the tree was felled. In addition, if a piece of wood is used for multiple purposes, there may be a significant delay between the felling of the tree and the final use in the context in which it is found. This is often referred to as the "old wood" problem. One example is the Bronze Age trackway at Withy Bed Copse, in England; the trackway was built from wood that had clearly been worked for other purposes before being re-used in the trackway. Another example is driftwood, which may be used as construction material. It is not always possible to recognize re-use. Other materials can present the same problem: for example, bitumen is known to have been used by some Neolithic communities to waterproof baskets; the bitumen's radiocarbon age will be greater than is measurable by the laboratory, regardless of the actual age of the context, so testing the basket material will give a misleading age if care is not taken. A separate issue, related to re-use, is that of lengthy use, or delayed deposition. For example, a wooden object that remains in use for a lengthy period will have an apparent age greater than the actual age of the context in which it is deposited.


title: Radiocarbon dating

text: Archaeology is not the only field to make use of radiocarbon dating. Radiocarbon dates can also be used in geology, sedimentology, and lake studies, for example. The ability to date minute samples using AMS has meant that palaeobotanists and palaeoclimatologists can use radiocarbon dating directly on pollen purified from sediment sequences, or on small quantities of plant material or charcoal. Dates on organic material recovered from strata of interest can be used to correlate strata in different locations that appear to be similar on geological grounds. Dating material from one location gives date information about the other location, and the dates are also used to place strata in the overall geological timeline.


title: Radiocarbon dating

text: Radiocarbon is also used to date carbon released from ecosystems, particularly to monitor the release of old carbon that was previously stored in soils as a result of human disturbance or climate change. Recent advances in field collection techniques also allow the radiocarbon dating of methane and carbon dioxide, which are important greenhouse gases.


title: Radiocarbon dating

text: The Pleistocene is a geological epoch that began about 2.6 million years ago. The Holocene, the current geological epoch, begins about 11,700 years ago when the Pleistocene ends. Establishing the date of this boundary − which is defined by sharp climatic warming − as accurately as possible has been a goal of geologists for much of the 20th century. At Two Creeks, in Wisconsin, a fossil forest was discovered (Two Creeks Buried Forest State Natural Area), and subsequent research determined that the destruction of the forest was caused by the Valders ice readvance, the last southward movement of ice before the end of the Pleistocene in that area. Before the advent of radiocarbon dating, the fossilized trees had been dated by correlating sequences of annually deposited layers of sediment at Two Creeks with sequences in Scandinavia. This led to estimates that the trees were between 24,000 and 19,000 years old, and hence this was taken to be the date of the last advance of the Wisconsin glaciation before its final retreat marked the end of the Pleistocene in North America. In 1952 Libby published radiocarbon dates for several samples from the Two Creeks site and two similar sites nearby; the dates were averaged to 11,404 BP with a standard error of 350 years. This result was uncalibrated, as the need for calibration of radiocarbon ages was not yet understood. Further results over the next decade supported an average date of 11,350 BP, with the results thought to be the most accurate averaging 11,600 BP. There was initial resistance to these results on the part of Ernst Antevs, the palaeobotanist who had worked on the Scandinavian varve series, but his objections were eventually discounted by other geologists. In the 1990s samples were tested with AMS, yielding (uncalibrated) dates ranging from 11,640 BP to 11,800 BP, both with a standard error of 160 years. Subsequently, a sample from the fossil forest was used in an interlaboratory test, with results provided by over 70 laboratories. These tests produced a median age of 11,788 ± 8 BP (2σ confidence) which when calibrated gives a date range of 13,730 to 13,550 cal BP. The Two Creeks radiocarbon dates are now regarded as a key result in developing the modern understanding of North American glaciation at the end of the Pleistocene.


title: Radiocarbon dating

text: In 1947, scrolls were discovered in caves near the Dead Sea that proved to contain writing in Hebrew and Aramaic, most of which are thought to have been produced by the Essenes, a small Jewish sect. These scrolls are of great significance in the study of Biblical texts because many of them contain the earliest known version of books of the Hebrew bible. A sample of the linen wrapping from one of these scrolls, the Great Isaiah Scroll, was included in a 1955 analysis by Libby, with an estimated age of 1,917 ± 200 years. Based on an analysis of the writing style, palaeographic estimates were made of the age of 21 of the scrolls, and samples from most of these, along with other scrolls which had not been palaeographically dated, were tested by two AMS laboratories in the 1990s. The results ranged in age from the early 4th century BC to the mid 4th century AD. In all but two cases the scrolls were determined to be within 100 years of the palaeographically determined age. The Isaiah scroll was included in the testing and was found to have two possible date ranges at a 2σ confidence level, because of the shape of the calibration curve at that point: there is a 15% chance that it dates from 355 to 295 BC, and an 84% chance that it dates from 210 to 45 BC. Subsequently, these dates were criticized on the grounds that before the scrolls were tested, they had been treated with modern castor oil in order to make the writing easier to read; it was argued that failure to remove the castor oil sufficiently would have caused the dates to be too young. Multiple papers have been published both supporting and opposing the criticism.


title: Radiocarbon dating

text: Soon after the publication of Libby's 1949 paper in "Science", universities around the world began establishing radiocarbon-dating laboratories, and by the end of the 1950s there were more than 20 active research laboratories. It quickly became apparent that the principles of radiocarbon dating were valid, despite certain discrepancies, the causes of which then remained unknown.


title: Radiocarbon dating

text: The development of radiocarbon dating has had a profound impact on archaeologyoften described as the "radiocarbon revolution". In the words of anthropologist R. E. Taylor, " data made a "world" prehistory possible by contributing a time scale that transcends local, regional and continental boundaries". It provides more accurate dating within sites than previous methods, which usually derived either from stratigraphy or from typologies (e.g. of stone tools or pottery); it also allows comparison and synchronization of events across great distances. The advent of radiocarbon dating may even have led to better field methods in archaeology since better data recording leads to a firmer association of objects with the samples to be tested. These improved field methods were sometimes motivated by attempts to prove that a date was incorrect. Taylor also suggests that the availability of definite date information freed archaeologists from the need to focus so much of their energy on determining the dates of their finds, and led to an expansion of the questions archaeologists were willing to research. For example, from the 1970s questions about the evolution of human behaviour were much more frequently seen in archaeology.


title: Radiocarbon dating

text: The dating framework provided by radiocarbon led to a change in the prevailing view of how innovations spread through prehistoric Europe. Researchers had previously thought that many ideas spread by diffusion through the continent, or by invasions of peoples bringing new cultural ideas with them. As radiocarbon dates began to prove these ideas wrong in many instances, it became apparent that these innovations must sometimes have arisen locally. This has been described as a "second radiocarbon revolution", and with regard to British prehistory, archaeologist Richard Atkinson has characterized the impact of radiocarbon dating as "radical ... therapy" for the "progressive disease of invasionism". More broadly, the success of radiocarbon dating stimulated interest in analytical and statistical approaches to archaeological data. Taylor has also described the impact of AMS, and the ability to obtain accurate measurements from very small samples, as ushering in a third radiocarbon revolution.


title: Radiocarbon dating

text: Occasionally, radiocarbon dating techniques date an object of popular interest, for example, the Shroud of Turin, a piece of linen cloth thought by some to bear an image of Jesus Christ after his crucifixion. Three separate laboratories dated samples of linen from the Shroud in 1988; the results pointed to 14th-century origins, raising doubts about the shroud's authenticity as an alleged 1st-century relic.


title: Radiocarbon dating

text: Researchers have studied other radioactive isotopes created by cosmic rays to determine if they could also be used to assist in dating objects of archaeological interest; such isotopes include , , , , and . With the development of AMS in the 1980s it became possible to measure these isotopes precisely enough for them to be the basis of useful dating techniques, which have been primarily applied to dating rocks. Naturally occurring radioactive isotopes can also form the basis of dating methods, as with potassium–argon dating, argon–argon dating, and uranium series dating. Other dating techniques of interest to archaeologists include thermoluminescence, optically stimulated luminescence, electron spin resonance, and fission track dating, as well as techniques that depend on annual bands or layers, such as dendrochronology, tephrochronology, and varve chronology.


title: Abbott and Costello

text: Abbott and Costello were an American comedy duo composed of comedians Bud Abbott and Lou Costello, whose work in radio, film, and television made them the most popular comedy team of the 1940s and 1950s, and the highest-paid entertainers in the world during the Second World War. Their patter routine "Who's on First?" is considered one of the greatest comedy routines of all time.


title: Abbott and Costello

text: While they had crossed paths a few times previously, the two comedians first worked together in 1935 at the Eltinge Burlesque Theater on 42nd Street in New York City. Their first performance resulted from Costello's regular partner becoming ill, and Abbott substituting for him.


title: Abbott and Costello

text: Other performers in the show, including Abbott's wife, encouraged a permanent pairing. The duo built an act by refining and reworking numerous burlesque sketches with Abbott as the devious straight man and Costello as the dimwitted comic.


title: Abbott and Costello

text: Decades later, when AMC moved the old theater further west on 42nd Street to its current location, giant balloons of Abbott and Costello were rigged to appear to pull it.


title: Abbott and Costello

text: The team's first known radio broadcast was on "The Kate Smith Hour" on February 3, 1938. At first, the similarities between their voices made it difficult for radio listeners (as opposed to stage audiences) to tell them apart during their rapid-fire repartee. As a result, Costello affected a high-pitched, childish voice. "Who's on First?" was first performed for a national radio audience the following month. They performed on the program as regulars for two years, while also landing roles in a Broadway revue, "The Streets of Paris", in 1939.


title: Abbott and Costello

text: After debuting their own program, "The Abbott and Costello Show", as Fred Allen's summer replacement in 1940, Abbott and Costello joined Edgar Bergen and Charlie McCarthy on "The Chase and Sanborn Hour" in 1941. Two of their films ("Hold That Ghost" and "Buck Privates") were adapted for radio that year. "Hold That Ghost" was presented as a half-hour adaptation on August 1, 1941 on Louella Parsons' "Hollywood Premiere", and "Buck Privates" was presented on "Lux Radio Theatre" as a one-hour adaptation on October 13, 1941. Their program returned in its own weekly time slot starting on October 8, 1942, with Camel cigarettes as sponsor.


title: Abbott and Costello

text: "The Abbott and Costello Show" mixed comedy with musical interludes (by vocalists such as Connie Haines, Ashley Eustis, the Delta Rhythm Boys, Skinnay Ennis, Marilyn Maxwell and the Les Baxter Singers).


title: Abbott and Costello

text: Among the show's regular and semi-regular performers were Joe Kirk (Costello's brother-in-law) as the excitable Sicilian immigrant Mr. Bacciagalupe, Artie Auerbach as Mr. Kitzel, Elvia Allman, Iris Adrian, Mel Blanc, Wally Brown, Sharon Douglas, Verna Felton, Sidney Fields, Frank Nelson, Martha Wentworth and Benay Venuta. Guest stars included Cary Grant, Frank Sinatra, The Andrews Sisters and Lucille Ball.


title: Abbott and Costello

text: Ken Niles was the show's longtime announcer, doubling as an exasperated foil to Costello, who routinely insulted his on-air wife (played by Elvia Allman). Niles was succeeded by Michael Roy, alternating over the years with Frank Bingman and Jim Doyle.


title: Abbott and Costello

text: The show went through several orchestras, including those of Ennis, Charles Hoff, Matty Matlock, Matty Malneck, Jack Meakin, Will Osborne, Fred Rich, Leith Stevens and Peter van Steeden.


title: Abbott and Costello

text: The show's writers included Howard Harris, Hal Fimberg, Parke Levy, Don Prindle, Eddie Cherkose (later known as Eddie Maxwell), Leonard B. Stern, Martin Ragaway, Paul Conlan and Eddie Forman, as well as producer Martin Gosch. Sound effects were handled primarily by Floyd Caton.


title: Abbott and Costello

text: In 1947, the show moved to ABC (the former NBC Blue Network). During their time on ABC the duo also hosted a 30-minute children's radio program ("The Abbott and Costello Children's Show") on Saturday mornings. The program featured child vocalist Anna Mae Slaughter and child announcer Johnny McGovern. It finished its run in 1949.


title: Abbott and Costello

text: In 1940, Universal Studios signed them for a musical, "One Night in the Tropics" starring Allan Jones and Nancy Kelly. Cast in supporting roles, Abbott and Costello stole the picture with several classic routines, including "Who's on First?". Signed to a two-picture contract, their second film, "Buck Privates" (1941), directed by Arthur Lubin and co-starring The Andrews Sisters, was a massive hit, earning $4 million at the box office and launching Abbott and Costello as stars.


title: Abbott and Costello

text: Their next film was a haunted house comedy, "Oh, Charlie!"; however, "Buck Privates" was so successful that the studio decided to delay the release so the team could hastily film and release a second service comedy. "In the Navy" (1941), co-starred crooner Dick Powell and the Andrews Sisters, and initially out-grossed "Buck Privates". Loew's Criterion in Manhattan was open until 5 a.m. to oblige over 49,000 customers during the film's first week.


title: Abbott and Costello

text: "Oh, Charlie" went back into production to add music featuring the Andrews Sisters and Ted Lewis. The film was eventually retitled "Hold That Ghost" (1941). The duo next appeared in "Ride 'Em Cowboy" (1941), with Dick Foran, but its release was delayed so they could appear in a third service comedy, "Keep 'Em Flying" (1941). This was their last film directed by Arthur Lubin. All of their 1941 films were big hits, and Abbott and Costello were voted the third biggest box office attraction in the country in 1941.


title: Abbott and Costello

text: Universal loaned the team to Metro-Goldwyn-Mayer for a musical comedy, "Rio Rita" (1942). During filming Abbott and Costello had their hand and foot prints set in concrete at what was then "Grauman's Chinese Theatre". Back at Universal they made "Pardon My Sarong" (1942), a spoof of South Sea Island movies; and "Who Done It?" (1942), a comedy-mystery.


title: Abbott and Costello

text: In 1942, exhibitors voted them the top box office stars in the country, and their earnings for the fiscal year were $789,026. The team did a 35-day tour during the summer of 1942 to promote and sell War Bonds. The Treasury Department credited them with $85 million in sales.


title: Abbott and Costello

text: After the tour the team starred in "It Ain't Hay" (1943), from a story by Damon Runyon; and "Hit the Ice" (1943).


title: Abbott and Costello

text: Costello was stricken with rheumatic fever upon his return from a winter tour of army bases in March 1943 and was bedridden for approximately six months. On November 4, 1943, the same day that Costello returned to radio after a one-year hiatus due to his illness, his infant son Lou Jr. (nicknamed "Butch" and born November 6, 1942) died in an accidental drowning in the family's swimming pool. Maxene Andrews remembers visiting Costello with sisters Patty and LaVerne during his illness, and remembered how Costello's demeanor changed after the tragic loss of his son, recalling, "He didn't seem as fun-loving and as warm...He seemed to anger easily...there was a difference in his attitude".


title: Abbott and Costello

text: After Costello recovered, the duo returned to MGM for "Lost in a Harem" (1944) then were back at Universal for "In Society" (1944), "Here Come the Co-Eds" (1945) and "The Naughty Nineties" (1945). Their third and final film for MGM was "Abbott and Costello in Hollywood" (1945).


title: Abbott and Costello

text: In 1945, a rift developed when Abbott hired a domestic servant who had been fired by Costello. Costello refused to speak to his partner except when performing. The following year they made two films, ("Little Giant" and "The Time of Their Lives"), in which they appeared as separate characters rather than as a team. This was likely the result of the tensions between them, plus the fact that their most recent films had not performed as well at the box office. Abbott resolved the rift when he suggested naming Costello's pet charity, a foundation for underprivileged children, the "Lou Costello Jr. Youth Foundation." The facility opened in 1947 and still serves the Boyle Heights district of Los Angeles.


title: Abbott and Costello

text: Abbott and Costello reunited as a team in "Buck Privates Come Home" (1947), a sequel to their 1941 hit. In "The Wistful Widow of Wagon Gap" (1947) they were supported by Marjorie Main. They signed a new contract with Universal which allowed them to appear in films outside of their studio contract. The first of these, "The Noose Hangs High" (1948), was distributed by Eagle-Lion.


title: Abbott and Costello

text: The team's next film, "Abbott and Costello Meet Frankenstein" (1948), co-starring Bela Lugosi and Lon Chaney Jr, was a massive hit and revitalized the duo's careers. It was followed by "Mexican Hayride" (1948), an adaptation of a Cole Porter musical without the songs. They followed with "Africa Screams" (1949) for Nassour Studios, an independent company which was released through United Artists. Back at Universal, they returned to horror comedy with "Abbott and Costello Meet the Killer, Boris Karloff" (1949).


title: Abbott and Costello

text: The pair was sidelined again for several months when Costello suffered a relapse of rheumatic fever. They returned to the screen in "Abbott and Costello in the Foreign Legion" (1950). They returned the following year in "Abbott and Costello Meet the Invisible Man" (1951); then "Comin' Round the Mountain" (1952), a hillbilly comedy.


title: Abbott and Costello

text: Their first color film, "Jack and the Beanstalk" (1952), was an independent production distributed by Warner Bros. After filming "Lost in Alaska" (1952) back at Universal, they made a second independent color movie, "Abbott and Costello Meet Captain Kidd" (1953) co-starring Charles Laughton, which was also distributed by Warner Bros.


title: Abbott and Costello

text: At Universal, they starred in "Abbott and Costello Go to Mars" (1953) and "Abbott and Costello Meet Dr. Jekyll and Mr. Hyde" (1953). They were forced to withdraw from "Fireman Save My Child" in 1954 due to Costello's ill health, and were replaced by lookalikes Hugh O'Brian and Buddy Hackett along with Spike Jones and his City Slickers. Their last two films for Universal were "Abbott and Costello Meet the Keystone Kops" (1955) and "Abbott and Costello Meet the Mummy" (1955). In 1956, they appeared in their final film together, "Dance With Me, Henry", an independent production released through United Artists.


title: Abbott and Costello

text: In January 1951, Abbott and Costello joined the roster of rotating hosts of "The Colgate Comedy Hour" on NBC. (Eddie Cantor and Martin and Lewis were among the others.) Each show was a live hour of vaudeville in front of an audience, revitalizing the comedians' performances and giving their old routines a new sparkle.


title: Abbott and Costello

text: From the fall of 1952 to the spring of 1954, a filmed half-hour series, "The Abbott and Costello Show", appeared in syndication on over 40 local stations across the United States. Loosely based on their radio series, the show cast the duo as unemployed wastrels. One of the show's running gags involved Abbott perpetually hounding Costello to get a job, while Abbott was happily unemployed. The show featured Sidney Fields as their landlord and Hillary Brooke as a neighbor and sometime love interest for Costello. Other regulars were future Stooge Joe Besser as Stinky, a whiny child in a Little Lord Fauntleroy suit; Gordon Jones as Mike the cop, who always lost patience with Costello; Joe Kirk, an Italian immigrant caricature whose role varied with the requirements of the script; and Bobby Barber, who played many "extra" parts.


title: Abbott and Costello

text: The simple plot lines were often an excuse to recreate comedy routines from their films and burlesque days, including "Who's on First?" Since Costello owned the series (with Abbott working on salary), this allowed them to own these versions of the classic routines as well. The 2nd season was more story-driven. There was no continuity. Although "The Abbott and Costello Show" originally ran for only two seasons, it found a larger viewership in reruns from the 1960s to the 1990s. The shows have also been released in three different DVD sets over the years.


title: Abbott and Costello

text: "Who's on First?" is Abbott and Costello's signature routine. "Time" magazine (December 26, 1999) named it the best comedy routine of the 20th century. The sketch was based on other earlier burlesque wordplay routines. They began honing the routine shortly after teaming up in 1936, and performed it in vaudeville in 1937 and 1938. It was first heard by a national radio audience on March 24, 1938, when the team were regulars on the Kate Smith radio show. By then, John Grant had been writing or adapting other sketches for the team and may have helped expand "Who's on First?" prior to its radio debut. He stayed on as their head writer into the 1950s.


title: Abbott and Costello

text: Depending upon the version, Abbott has either organized a new baseball team and the players have nicknames, or he points out the proliferation of nicknames in baseball (citing St. Louis Cardinals sibling pitchers Dizzy and Daffy Dean) before launching into the routine. The infielders' nicknames are Who (first base), What (second base) and I Don't Know (third base). The key to the routine is Costello's mounting frustration set against Abbott's unyielding formality. Audio recordings are readily available on the Internet.


title: Abbott and Costello

text: "Who's on First?" is believed to be available in as many as twenty versions, ranging from one minute to up to ten minutes. The team could time the routine at will, adding or deleting portions as needed for films, radio or television. The longest version is seen in "The Actors' Home" episode of their filmed TV series, running approximately eight minutes. A live performance commemorating the opening day of the Lou Costello Jr Youth Foundation in 1947 was recorded, and has been included in numerous comedy albums. The team's final performance of "Who's on First?" on TV was on Steve Allen's variety show in 1957.


title: Abbott and Costello

text: Abbott and Costello both married performers they met in burlesque. Abbott wed Betty Smith, a dancer and comedienne, in 1918, and Costello married a chorus girl, Anne Battler, in 1934. The Costellos had four children; the Abbotts adopted two. Abbott and Costello faced personal demons at times. Both were inveterate gamblers and had serious health problems. Abbott suffered from epilepsy and turned to alcohol for seizure management. Costello had occasional, near-fatal bouts with rheumatic fever.


title: Abbott and Costello

text: In the 1950s, Abbott and Costello's popularity waned with the emergence of Dean Martin and Jerry Lewis. Another reason for their decline was overexposure. Each year they made two new films, while Realart Pictures re-issued their older hits; their filmed television series was widely syndicated, and the same routines appeared frequently on the Colgate program. (Writer Parke Levy told Jordan R. Young, in "The Laugh Crafters: Comedy Writing in Radio and TV's Golden Age", that he was stunned to learn that the pair were afraid to perform new material.)


title: Abbott and Costello

text: Universal dropped the comedy team in 1955 after they could not agree on contract terms. In the early 1950s, the Internal Revenue Service charged them for back taxes, forcing them to sell their homes and most of their assets, including the rights to most of their films.


title: Abbott and Costello

text: In 1956, they made one independent film, "Dance with Me, Henry", and Costello was the subject of the television program "This Is Your Life", then formally dissolved their partnership in 1957. In his posthumously published 1959 autobiography, "My Wicked, Wicked Ways", Errol Flynn claims that he triggered the breakup. Flynn, a chronic practical joker, invited them, along with their wives and children, to his house for dinner, and afterwards, he commenced to show a home movie that "accidentally" turned out to be hard-core pornography. While Flynn pretended to be baffled, Costello and Abbott each blamed the other for the film's substitution.


title: Abbott and Costello

text: In his last years, Costello made about ten solo appearances on "The Steve Allen Show" doing many of the old routines without Abbott. Costello performed stand-up in Las Vegas, and appeared in episodes of "GE Theater" and "Wagon Train". On March 3, 1959, not long after completing his lone solo film, "The 30 Foot Bride of Candy Rock", he died of a heart attack three days short of his 53rd birthday.


title: Abbott and Costello

text: Abbott attempted a comeback in 1960 with Candy Candido. Although the new act received good reviews, Abbott quit, saying, "No one could ever live up to Lou." Abbott made a solo, dramatic appearance on an episode of "General Electric Theater" in 1961. In 1966, Abbott voiced his character in a series of 156 five-minute "Abbott and Costello" cartoons made by Hanna-Barbera. Costello's character was voiced by Stan Irwin. Bud Abbott died of cancer on April 24, 1974.


title: Abbott and Costello

text: For a number of years Abbott and Costello were ranked among the most popular stars in the US according to the Quigley Publishers Poll of Exhibitors:


title: Abbott and Costello

text: The 1960s cartoon series was not the first time Abbott and Costello were animated. During the height of their popularity in the 1940s, Warner Bros.'s Looney Tunes/Merrie Melodies animation unit produced 3 cartoons featuring the pair as cats or mice named "Babbit and Catstello". One of the cartoons, Bob Clampett's "A Tale of Two Kitties" (1942), introduced Tweety. The other cartoons are "A Tale of Two Mice" and "Mouse-Merized Cat". In all three cartoons, Tedd Pierce (normally a storyman/writer for the cartoons) and Mel Blanc, respectively, provide voice impressions of the comedy duo.


title: Abbott and Costello

text: The revival of their former television series in syndicated reruns in the late 1960s and early 1970s helped spark renewed interest in the duo, as did the televising of many of their old film hits. In 1994, comedian Jerry Seinfeld—who says Abbott and Costello were strong influences on his work—hosted a television special "Abbott and Costello Meet Jerry Seinfeld" (the title refers to the duo's popular film series in which they met some of Universal's famed horror picture characters), on NBC; the special was said to have been seen in 20 million homes.


title: Abbott and Costello

text: Abbott and Costello were frequently referred to in 1940s Looney Tunes cartoons, such as "A Tale of Two Kitties" (1942), "A Tale of Two Mice" (1945), "Hollywood Canine Canteen", "Hollywood Daffy" and "The Mouse-Merized Cat" (all three from 1946). A catchphrase from Abbott and Costello's radios show, ""I'm only three and a half years old"" was often quoted in these cartoons too. Even Bugs Bunny's famous catchphrase, ""Ain't I a stinker?"" was borrowed from Lou Costello.


title: Abbott and Costello

text: Although they are not inductees of the Hall itself, Abbott and Costello are among the few non-baseball personnel to be memorialized in the Baseball Hall of Fame. A plaque and a gold record of the "Who's on First?" sketch have been on permanent display there since 1956, and the routine runs on an endless video loop in the exhibit area.


title: Abbott and Costello

text: Their "Who's on First?" routine has been referred to numerous times. In the 1988 movie "Rain Man", Dustin Hoffman's autistic character Raymond Babbitt recites an affectless "Who's on First?" as a defence mechanism. In 1982, "Tonight Show" host Johnny Carson performed a topical sketch as then-President Ronald Reagan in which "Who's on First?"-style confusion arose from the names of Interior Secretary James Watt, Palestinian leader Yassir Arafat and Chinese leader Hu Yaobang.


title: Abbott and Costello

text: The comedy group "The Credibility Gap" performed a rock and roll update of "Who's on First?" using the names of rock groups The Who, The Guess Who, and Yes, recorded and released on their first album, "The Bronze Age of Radio". On the January 13, 2001, episode of "Saturday Night Live" host Charlie Sheen and "SNL" cast-member Rachel Dratch performed a modified version of "Who's on First?" in a sketch. NBC's "Studio 60 on the Sunset Strip" (2006), a drama about life backstage at a television comedy series, used "Who's on First?" as a plot device.


title: Abbott and Costello

text: A TV movie called "Bud and Lou", based on a book by Hollywood correspondent Bob Thomas, was broadcast in 1978. Starring Harvey Korman as Bud Abbott and Buddy Hackett as Lou Costello, the film told the duo's life story, focusing on Costello and portraying him as volatile and petty.


title: Abbott and Costello

text: Jerry Seinfeld is an avid Abbott and Costello fan and their influence on him was celebrated in a 1994 NBC special, "Abbott and Costello Meet Jerry Seinfeld". Seinfeld's TV series includes numerous references to the team. George Costanza's middle name is "Louis", after Costello. "The Old Man (Seinfeld)" (Season 4, Episode 18, aired February 18, 1993) featured a cantankerous old man named "Sid Fields" (played by veteran actor Bill Erwin) as a tribute to the landlord on the Abbott and Costello TV show. A friend of Kramer's is named Mickey Abbott. A copywriter for the J. Peterman catalog is named Eddie Sherman, after the team's longtime agent. In Episode 30, Kramer hears the famous Abbott and Costello line, "His father was a mudder. His mother was a mudder."


title: Abbott and Costello

text: In 1991, the US Postal Service featured Abbott and Costello on a first-class stamp, part of a "Comedian Commemorative Issue", illustrated by Al Hirschfeld.


title: Abbott and Costello

text: In 2003, Montclair State University dedicated a student residential complex named The Abbott and Costello Center on Clove Road in the Little Falls portion of the university's campus.


title: Abbott and Costello

text: In "", a 1993 spoof comedy directed by Mel Brooks, Dick Van Patten played the part of the Abbot. At one point, a man who looked and sounded like Lou Costello (played by Chuck McCann) yelled "Hey, Abbott!", in exactly the same way Lou did in the Abbott and Costello movies, repeating a joke from Brooks' Robin Hood sitcom "When Things Were Rotten" in which Van Patten shouted the line. Patten responds, "I hate that guy!"


title: Abbott and Costello

text: In 2015, a non-profit fan film was produced titled "Abbott & Costello Meet Superman." The film was screened at the Superman Celebration Film Festival in Metropolis Illinois and is currently streaming on YouTube. Abbott and Costello are played by two actors from New York, Aaron M. Lambert and Jake Navatka.


title: Abbott and Costello

text: In the 2016 sci-fi movie "Arrival", the two Heptapods (alien beings) are named Abbott and Costello by the scientists, because the one named Abbott is taller and quieter while the one named Costello is shorter and chattier. The names also have extra-diegetic significance as two of the main themes in the movie are linguistics and (mis)communication, which mirrors themes of the "Who's on First?" routine.


title: Kelly Marie Tran

text: Kelly Marie Tran (born Loan Tran, January 17, 1989) is an American actress. She began acting in 2011, with most of her roles being in short film and television. She came to global prominence for her role as Rose Tico in the "Star Wars" sequel trilogy films "" (2017) and "" (2019). She also voiced Princess Raya in the Disney film "Raya and the Last Dragon" (2021) and Dawn Betterman in the DreamWorks Animation film "" (2020).


title: Kelly Marie Tran

text: Kelly Marie Tran was born on January 17, 1989, in San Diego, California. Her parents were refugees from Vietnam who fled the country following the Vietnam War. As a child, her father was homeless and grew up on the streets of Vietnam. After moving to the United States, her father worked at Burger King to support the family, and her mother worked at a funeral home.


title: Kelly Marie Tran

text: Tran attended Westview High School in San Diego and worked at a yogurt shop to earn money for head shots. Tran then graduated from UCLA with a B.A. in communications.


title: Kelly Marie Tran

text: Her early credits consisted of primarily CollegeHumor videos and small TV roles. She landed a commercial agent in 2011, who got Tran to take improv classes at the Upright Citizens Brigade. At The Second City, Tran is part of the all-female, Asian-American improv group, Number One Son.


title: Kelly Marie Tran

text: In 2013, she starred in the web series "Ladies Like Us". In 2015, Tran was working as an assistant at a creative recruiting firm in Century City.


title: Kelly Marie Tran

text: In 2015, Tran was cast as Rose Tico in "Star Wars: The Last Jedi". Rose Tico is a rebel mechanic who joins up with main character Finn after the sacrifice of her oldest sister, Paige Tico (Veronica Ngo), a gunner trained by Resistance commander Poe Dameron. When she went to shoot her scenes in England in early 2016, she was required to keep her role secret, so she told her family she was making an independent film in Canada. "The Last Jedi" made Tran the first Asian-American woman to have a major role in a "Star Wars" film. In 2017, she also became the first woman of Asian descent to appear on the cover of "Vanity Fair" when she appeared on the cover of the summer 2017 issue with actor John Boyega (who played Finn) and Oscar Isaac (who played X-wing fighter pilot Poe Dameron).


title: Kelly Marie Tran

text: Tran plays the lead role of Kaitlin Le in Radiotopia's mystery thriller podcast "Passenger List". She was a series regular on the Facebook Watch series "Sorry for Your Loss."


title: Kelly Marie Tran

text: Tran voiced Raya in the Walt Disney Animation Studios production "Raya and the Last Dragon", replacing Cassie Steele.


title: Kelly Marie Tran

text: Tran was set to voice Val Little in the Disney+ series "Monsters at Work", but was replaced by Mindy Kaling. She has also been cast as Dawn in the film "", replacing Kat Dennings.


title: Kelly Marie Tran

text: Tran is an executive producer on Jeremy Workman's 2021 documentary "Lily Topples the World", which follows 21-year-old domino toppling artist Lily Hevesh. The documentary premiered to critical acclaim at the 2021 South by Southwest Film Festival, where it won the Grand Jury Prize for Best Documentary.


title: Kelly Marie Tran

text: Tran is also an executive producer of the spoken-word poetry ensemble film "Summertime", marking her second collaboration with "Raya and the Last Dragon" director Carlos López Estrada. Tran and Estrada announced that they were establishing a new production company called Antigravity Academy in November 2022, intending to help produce entertainment from and about people from historically excluded communities.


title: Kelly Marie Tran

text: Tran will next star in Tayarisha Poe's second feature film, "The Young Wife", alongside Kiersey Clemons, and in "Me, Myself & The Void". She is also currently developing a biopic about civil rights activist and her close friend Amanda Nguyen.


title: Kelly Marie Tran

text: After the release of "Star Wars: The Last Jedi" in December 2017, Tran became the subject of racist and sexist attacks over the Internet, including insults about her ethnicity and size. She was the target of racist trolling on Twitter; in one example, Internet personality Paul Ray Ramsey mocked her size. Her character Rose Tico's entry on Wookieepedia, an online encyclopedia about the "Star Wars" universe, was edited by internet trolls to include racist and vulgar comments, which drew national media attention. Fandom, the wiki hosting service that operated the domain, removed the offensive edits, protected the page, and publicly condemned the vandalism.


title: Kelly Marie Tran

text: After months of online harassment, Tran deleted all of her Instagram posts in June 2018, and replaced the account bio with, "Afraid, but doing it anyway." She also pursued therapy following the harassment. Subsequently, several cast and crew members of "The Last Jedi" condemned the attacks and spoke out in defense of Tran, including writer-director Rian Johnson and actors John Boyega, Domhnall Gleeson, and Mark Hamill, who posted a picture of himself with Tran and wrote the caption, "What's not to love? #GetALifeNerds". Johnson branded the attackers as "manbabies", and said they represent a "few unhealthy people" and not the "vast majority" of "Star Wars" fans. Other celebrities voiced support for Tran as well, including Stephen Colbert, Josh Gad, Kumail Nanjiani, Gabrielle Union, Elijah Wood, and Edgar Wright. In less than one day, more than 20,000 fans retweeted a message of support for Tran from a fan on Twitter that sought to "drown out the manbabies". She was also shown support at the 2018 San Diego Comic-Con during a "Rally for Rose", where fans appeared in cosplay attire as her "Star Wars" character Rose Tico or wore "Rose for Hope" T-shirts. Fans posted about the event on social media using the hashtags #ForceOutHate and #RallyForRose. At "Star Wars" Celebration in April 2019, Tran received a standing ovation from fans, causing her to tear up at the reception.


title: Kelly Marie Tran

text: In August 2018, Tran penned an essay on the subject for "The New York Times" entitled "Kelly Marie Tran: I Won't Be Marginalized by Online Harassment". She described how the matter made her self-conscious, writing that the attacks reinforced the ones she had long faced as a Vietnamese-American, and which sought to reinforce a narrative that Asians should be marginalized and treated only as minor characters, both in stories and in real life. Tran further wrote that the ordeal reached a point where she began to believe the negative remarks about her, stating that they had sent her "down a spiral of self-hate, into the darkest recesses of my mind, places where I tore myself apart, where I put their words above my own self-worth." She concluded with, "You might know me as Kelly. I am the first woman of color to have a leading role in a "Star Wars" movie. I am the first Asian woman to appear on the cover of "Vanity Fair". My real name is Loan. And I am just getting started." Tran later said the essay was difficult to write, but also "probably one of the proudest moments of [her] career thus far."


title: Japanese writing system

text: The modern Japanese writing system uses a combination of logographic kanji, which are adopted Chinese characters, and syllabic kana. Kana itself consists of a pair of syllabaries: hiragana, used primarily for native or naturalised Japanese words and grammatical elements; and katakana, used primarily for foreign words and names, loanwords, onomatopoeia, scientific names, and sometimes for emphasis. Almost all written Japanese sentences contain a mixture of kanji and kana. Because of this mixture of scripts, in addition to a large inventory of kanji characters, the Japanese writing system is considered to be one of the most complicated currently in use.


title: Japanese writing system

text: Several thousand kanji characters are in regular use, which mostly originate from traditional Chinese characters. Others made in Japan are referred to as “Japanese kanji” (; also known as “country’s kanji” ). Each character has an intrinsic meaning (or range of meanings), and most have more than one pronunciation, the choice of which depends on context. Japanese primary and secondary school students are required to learn 2,136 jōyō kanji as of 2010. The total number of kanji is well over 50,000, though few if any native speakers know anywhere near this number.


title: Japanese writing system

text: In modern Japanese, the hiragana and katakana syllabaries each contain 46 basic characters, or 71 including diacritics. With one or two minor exceptions, each different sound in the Japanese language (that is, each different syllable, strictly each mora) corresponds to one character in each syllabary. Unlike kanji, these characters intrinsically represent sounds only; they convey meaning only as part of words. Hiragana and katakana characters also originally derive from Chinese characters, but they have been simplified and modified to such an extent that their origins are no longer visually obvious.


title: Japanese writing system

text: Texts without kanji are rare; most are either children's books — since children tend to know few kanji at an early age — or early electronics such as computers, phones, and video games, which could not display complex graphemes like kanji due to both graphical and computational limitations.


title: Japanese writing system

text: To a lesser extent, modern written Japanese also uses initialisms from the Latin alphabet, for example in terms such as "BC/AD", "a.m./p.m.", "FBI", and "CD". Romanized Japanese is most frequently used by foreign students of Japanese who have not yet mastered kana, and by native speakers for computer input.


title: Japanese writing system

text: are logographic characters (based on traditional ones) taken from Chinese script and used in the writing of Japanese.


title: Japanese writing system

text: It is known from archaeological evidence that the first contacts that the Japanese had with Chinese writing took place in the 1st century AD, during the late Yayoi period. However, the Japanese people of that era probably had little to no comprehension of the script, and they would remain relatively illiterate until the 5th century AD in the Kofun period, when writing in Japan became more widespread.


title: Japanese writing system

text: They are used to write most content words of native Japanese or (historically) Chinese origin, which include the following:


title: Japanese writing system

text: Some Japanese words are written with different kanji depending on the specific usage of the word—for instance, the word "naosu" (to fix, or to cure) is written when it refers to curing a person, and when it refers to fixing an object.


title: Japanese writing system

text: Most kanji have more than one possible pronunciation (or "reading"), and some common kanji have many. These are broadly divided into "on'yomi", which are readings that approximate to a Chinese pronunciation of the character at the time it was adopted into Japanese, and "kun'yomi", which are pronunciations of native Japanese words that correspond to the meaning of the kanji character. However, some kanji terms have pronunciations that correspond to neither the "on'yomi" nor the "kun'yomi" readings of the individual kanji within the term, such as ("ashita", "tomorrow") and ("otona", "adult").


title: Japanese writing system

text: Unusual or nonstandard kanji readings may be glossed using furigana. Kanji compounds are sometimes given arbitrary readings for stylistic purposes. For example, in Natsume Sōseki's short story "The Fifth Night", the author uses for "tsunagatte", the gerundive "-te" form of the verb "tsunagaru" ("to connect"), which would usually be written as or . The word , meaning "connection", is normally pronounced "setsuzoku".


title: Japanese writing system

text: emerged as a manual simplification via cursive script of the most phonetically widespread kanji among those who could read and write during the Heian period (794-1185). The main creators of the current hiragana were ladies of the Japanese imperial court, that used the script in the writing of personal communications and literature.


title: Japanese writing system

text: There is also some flexibility for words with common kanji renditions to be instead written in hiragana, depending on the individual author's preference (all Japanese words "can" be spelled out entirely in hiragana or katakana, even when they are normally written using kanji). Some words are colloquially written in hiragana and writing them in kanji might give them a more formal tone, while hiragana may impart a softer or more emotional feeling. For example, the Japanese word "kawaii", the Japanese equivalent of "cute", can be written entirely in hiragana as in , or with kanji as .


title: Japanese writing system

text: Some lexical items that are normally written using kanji have become grammaticalized in certain contexts, where they are instead written in hiragana. For example, the root of the verb ("miru", "see") is normally written with the kanji for the "mi" portion. However, when used as a supplementary verb as in 試してみる ("tameshite miru") meaning "to try out", the whole verb is typically written in hiragana as , as we see also in ("tabete miru", "try to eat [it] and see").


title: Japanese writing system

text: emerged around the 9th century, in the Heian period, when Buddhist monks created a syllabary derived from Chinese characters to simplify their reading, using portions of the characters as a kind of shorthand. The origin of the alphabet is attributed to the monk Kūkai.


title: Japanese writing system

text: Katakana can also be used to impart the idea that words are spoken in a foreign or otherwise unusual accent; for example, the speech of a robot.


title: Japanese writing system

text: The first contact of the Japanese with the Latin alphabet occurred in the 16th century, during the Muromachi period, when they had contact with Portuguese navigators, the first European people to visit the Japanese islands. The earliest Japanese romanization system was based on Portuguese orthography. It was developed around 1548 by a Japanese Catholic named Anjirō.


title: Japanese writing system

text: Arabic numerals (as opposed to traditional kanji numerals) are often used to write numbers in horizontal text, especially when numbering things rather than indicating a quantity, such as telephone numbers, serial numbers and addresses. Arabic numerals were introduced in Japan probably at the same time as the Latin alphabet, in the 16th century during the Muromachi period, the first contact being via Portuguese navigators. These numerals did not originate in Europe, as the Portuguese inherited them during the Arab occupation of the Iberian peninsula. See also Japanese numerals.


title: Japanese writing system

text: , a set of archaic kana made obsolete by the Meiji reformation, are sometimes used to impart an archaic flavor, like in items of food (esp. soba).


title: Japanese writing system

text: "Jukujikun" refers to instances in which words are written using "kanji" that reflect the meaning of the word though the pronunciation of the word is entirely unrelated to the usual pronunciations of the constituent "kanji". Conversely, "ateji" refers to the employment of "kanji" that appear solely to represent the sound of the compound word but are, conceptually, utterly unrelated to the signification of the word.


title: Japanese writing system

text: Sentences are commonly written using a combination of all three Japanese scripts: kanji (in red), hiragana (in purple), and katakana (in orange), and in limited instances also include


title: Japanese writing system

text: The same text can be transliterated to the Latin alphabet ("rōmaji"), although this will generally only be done for the convenience of foreign language speakers:


title: Japanese writing system

text: All words in modern Japanese can be written using hiragana, katakana, and rōmaji, while only some have Kanji. Words that have no dedicated kanji may still be written with kanji by employing either ateji (like in man'yogana, から = 可良) or jukujikun, like in the title of とある科学の超電磁砲 (超電磁砲 being used to represent レールガン).


title: Japanese writing system

text: Although rare, there are some words that use all three scripts in the same word. An example of this is the term くノ一 ("rōmaji": "kunoichi"), which uses a hiragana, a katakana, and a kanji character, in that order. It is said that if all three characters are put in the same kanji "square", they all combine to create the kanji (woman/female). Another example is (rōmaji: "keshigomu") which means "eraser", and uses a kanji, a hiragana, and two katakana characters, in that order.


title: Japanese writing system

text: A statistical analysis of a corpus of the Japanese newspaper "Asahi Shimbun" from the year 1993 (around 56.6 million tokens) revealed:


title: Japanese writing system

text: Collation (word ordering) in Japanese is based on the kana, which express the pronunciation of the words, rather than the kanji. The kana may be ordered using two common orderings, the prevalent "gojūon" (fifty-sound) ordering, or the old-fashioned "iroha" ordering. Kanji dictionaries are usually collated using the radical system, though other systems, such as SKIP, also exist.


title: Japanese writing system

text: Traditionally, Japanese is written in a format called , which was inherited from traditional Chinese practice. In this format, the characters are written in columns going from top to bottom, with columns ordered from right to left. After reaching the bottom of each column, the reader continues at the top of the column to the left of the current one.


title: Japanese writing system

text: Modern Japanese also uses another writing format, called . This writing format is horizontal and reads from left to right, as in English.


title: Japanese writing system

text: A book printed in tategaki opens with the spine of the book to the right, while a book printed in yokogaki opens with the spine to the left.


title: Japanese writing system

text: Japanese is normally written without spaces between words, and text is allowed to wrap from one line to the next without regard for word boundaries. This convention was originally modelled on Chinese writing, where spacing is superfluous because each character is essentially a word in itself (albeit compounds are common). However, in kana and mixed kana/kanji text, readers of Japanese must work out where word divisions lie based on an understanding of what makes sense. For example, must be mentally divided as ("Anata wa okaasan ni sokkuri ne", "You're just like your mother"). In rōmaji, it may sometimes be ambiguous whether an item should be transliterated as two words or one. For example, , "to love", composed of ("ai", "love") and ("suru", "to do", here a verb-forming suffix), is variously transliterated as "aisuru" or .


title: Japanese writing system

text: Words in potentially unfamiliar foreign compounds, normally transliterated in katakana, may be separated by a punctuation mark called a "nakaguro" (, "middle dot") to aid Japanese readers. For example, (Bill Gates). This punctuation is also occasionally used to separate native Japanese words, especially in concatenations of kanji characters where there might otherwise be confusion or ambiguity about interpretation, and especially for the full names of people.


title: Japanese writing system

text: The Japanese full stop (。) and comma (、) are used for similar purposes to their English equivalents, though comma usage can be more fluid than is the case in English. The question mark (？) is not used in traditional or formal Japanese, but it may be used in informal writing, or in transcriptions of dialogue where it might not otherwise be clear that a statement was intoned as a question. The exclamation mark (！) is restricted to informal writing. Colons and semicolons are available but are not common in ordinary text. Quotation marks are written as 「 ... 」, and nested quotation marks as 『 ... 』. Several bracket styles and dashes are available.


title: Japanese writing system

text: Japan's first encounters with Chinese characters may have come as early as the 1st century AD with the King of Na gold seal, said to have been given by Emperor Guangwu of Han in AD 57 to a Japanese emissary. However, it is unlikely that the Japanese became literate in Chinese writing any earlier than the 4th century AD.


title: Japanese writing system

text: Initially Chinese characters were not used for writing Japanese, as literacy meant fluency in Classical Chinese, not the vernacular. Eventually a system called developed, which, along with kanji and something very similar to Chinese grammar, employed diacritics to hint at the Japanese translation. The earliest written history of Japan, the , compiled sometime before 712, was written in kanbun. Even today Japanese high schools and some junior high schools teach kanbun as part of the curriculum.


title: Japanese writing system

text: No full-fledged script for written Japanese existed until the development of , which appropriated kanji for their phonetic value (derived from their Chinese readings) rather than their semantic value. Man'yōgana was initially used to record poetry, as in the , compiled sometime before 759, whence the writing system derives its name. Some scholars claim that man'yōgana originated from Baekje, but this hypothesis is denied by mainstream Japanese scholars. The modern kana, namely hiragana and katakana, are simplifications and systemizations of man'yōgana.


title: Japanese writing system

text: Due to the large number of words and concepts entering Japan from China which had no native equivalent, many words entered Japanese directly, with a similar pronunciation to the original Chinese. This Chinese-derived reading is known as , and this vocabulary as a whole is referred to as Sino-Japanese in English and in Japanese. At the same time, native Japanese already had words corresponding to many borrowed kanji. Authors increasingly used kanji to represent these words. This Japanese-derived reading is known as . A kanji may have none, one, or several on'yomi and kun'yomi. Okurigana are written after the initial kanji for verbs and adjectives to give inflection and to help disambiguate a particular kanji's reading. The same character may be read several different ways depending on the word. For example, the character is read "i" as the first syllable of , "okona" as the first three syllables of , "gyō" in the compound word , "kō" in the word , and "an" in the word .


title: Japanese writing system

text: Some linguists have compared the Japanese borrowing of Chinese-derived vocabulary as akin to the influx of Romance vocabulary into English during the Norman conquest of England. Like English, Japanese has many synonyms of differing origin, with words from both Chinese and native Japanese. Sino-Japanese is often considered more formal or literary, just as latinate words in English often mark a higher register.


title: Japanese writing system

text: The significant reforms of the 19th century Meiji era did not initially impact the Japanese writing system. However, the language itself was changing due to the increase in literacy resulting from education reforms, the massive influx of words (both borrowed from other languages or newly coined), and the ultimate success of movements such as the influential which resulted in Japanese being written in the colloquial form of the language instead of the wide range of historical and classical styles used previously. The difficulty of written Japanese was a topic of debate, with several proposals in the late 19th century that the number of kanji in use be limited. In addition, exposure to non-Japanese texts led to unsuccessful proposals that Japanese be written entirely in kana or rōmaji. This period saw Western-style punctuation marks introduced into Japanese writing.


title: Japanese writing system

text: In 1900, the Education Ministry introduced three reforms aimed at improving the education in Japanese writing:


title: Japanese writing system

text: The first two of these were generally accepted, but the third was hotly contested, particularly by conservatives, to the extent that it was withdrawn in 1908.


title: Japanese writing system

text: The partial failure of the 1900 reforms combined with the rise of nationalism in Japan effectively prevented further significant reform of the writing system. The period before World War II saw numerous proposals to restrict the number of kanji in use, and several newspapers voluntarily restricted their kanji usage and increased usage of furigana; however, there was no official endorsement of these, and indeed much opposition. However, one successful reform was the standardization of hiragana, which involved reducing the possibilities of writing down Japanese morae down to only one hiragana character per morae, which led to labeling all the other previously used hiragana as hentaigana and discarding them in daily use.


title: Japanese writing system

text: The period immediately following World War II saw a rapid and significant reform of the writing system. This was in part due to influence of the Occupation authorities, but to a significant extent was due to the removal of traditionalists from control of the educational system, which meant that previously stalled revisions could proceed. The major reforms were:


title: Japanese writing system

text: At one stage, an advisor in the Occupation administration proposed a wholesale conversion to rōmaji, but it was not endorsed by other specialists and did not proceed.


title: Japanese writing system

text: In addition, the practice of writing horizontally in a right-to-left direction was generally replaced by left-to-right writing. The right-to-left order was considered a special case of vertical writing, with columns one character high, rather than horizontal writing per se; it was used for single lines of text on signs, etc. (e.g., the station sign at Tokyo reads ).