title: Liquid chromatography–mass spectrometry

text: In HPLC, typically 20 μl of the sample of interest are injected into the mobile phase stream delivered by a high pressure pump. The mobile phase containing the analytes permeates through the stationary phase bed in a definite direction. The components of the mixture are separated depending on their chemical affinity with the mobile and stationary phases. The separation occurs after repeated sorption and desorption steps occurring when the liquid interacts with the stationary bed. The liquid solvent (mobile phase) is delivered under high pressure (up to 400 bar or 300.000 torr) into a packed column containing the stationary phase. The high pressure is necessary to achieve a constant flow rate for reproducible chromatography experiments. Depending on the partitioning between the mobile and stationary phases, the components of the sample will flow out of the column at different times. The column is the most important component of the LC system and is designed to withstand the high pressure of the liquid. Conventional LC columns are 100–300 mm long with outer diameter of 6.4 mm (1/4 inch) and internal diameter of 3.0–4.6 mm. For applications involving LC-MS, the length of chromatography columns can be shorter (30–50 mm) with 3–5 μm diameter packing particles. In addition to the conventional model, other LC columns are the narrow bore, microbore, microcapillary, and nano-LC models. These columns have smaller internal diameters, allow for a more efficient separation, and handle liquid flows under 1 ml/min (the conventional flow-rate). In order to improve separation efficiency and peak resolution, ultra performance liquid chromatography (UHPLC) can be used instead of HPLC. This LC variant uses columns packed with smaller silica particles (~1.7 μm diameter) and requires higher operating pressures in the range of 310000 to 775000 torr (6000 to 15000 psi, 400 to 1034 bar).


title: Liquid chromatography–mass spectrometry

text: Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio ("m/z)" of charged particles (ions). Although there are many different kinds of mass spectrometers, all of them make use of electric or magnetic fields to manipulate the motion of ions produced from an analyte of interest and determine their "m/z." The basic components of a mass spectrometer are the ion source, the mass analyzer, the detector, and the data and vacuum systems. The ion source is where the components of a sample introduced in a MS system are ionized by means of electron beams, photon beams (UV lights), laser beams or corona discharge. In the case of electrospray ionization, the ion source moves ions that exist in liquid solution into the gas phase. The ion source converts and fragments the neutral sample molecules into gas-phase ions that are sent to the mass analyzer. While the mass analyzer applies the electric and magnetic fields to sort the ions by their masses, the detector measures and amplifies the ion current to calculate the abundances of each mass-resolved ion. In order to generate a mass spectrum that a human eye can easily recognize, the data system records, processes, stores, and displays data in a computer.


title: Liquid chromatography–mass spectrometry

text: The mass spectrum can be used to determine the mass of the analytes, their elemental and isotopic composition, or to elucidate the chemical structure of the sample. MS is an experiment that must take place in gas phase and under vacuum (1.33 * 10 to 1.33 * 10 pascal). Therefore, the development of devices facilitating the transition from samples at higher pressure and in condensed phase (solid or liquid) into a vacuum system has been essential to develop MS as a potent tool for identification and quantification of organic compounds like peptides. MS is now in very common use in analytical laboratories that study physical, chemical, or biological properties of a great variety of compounds. Among the many different kinds of mass analyzers, the ones that find application in LC-MS systems are the quadrupole, time-of-flight (TOF), ion traps, and hybrid quadrupole-TOF (QTOF) analyzers.


title: Liquid chromatography–mass spectrometry

text: The interface between a liquid phase technique (HPLC) with a continuously flowing eluate, and a gas phase technique carried out in a vacuum was difficult for a long time. The advent of electrospray ionization changed this. Currently, the most common LC-MS interfaces are electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo-ionization (APPI). These are newer MS ion sources that facilitate the transition from a high pressure environment (HPLC) to high vacuum conditions needed at the MS analyzer. Although these interfaces are described individually, they can also be commercially available as dual ESI/APCI, ESI/APPI, or APCI/APPI ion sources. Various deposition and drying techniques were used in the past (e.g., moving belts) but the most common of these was the off-line MALDI deposition. A new approach still under development called direct-EI LC-MS interface, couples a nano HPLC system and an electron ionization equipped mass spectrometer.


title: Liquid chromatography–mass spectrometry

text: ESI interface for LC-MS systems was developed by Fenn and collaborators in 1988. This ion source/ interface can be used for the analysis of moderately polar molecules (e.g., metabolites, xenobiotics, and peptides). The liquid eluate coming out of the LC column is pumped through a metal capillary kept at 3 to 5 kV. The liquid is nebulized at the tip of the capillary and a fine spray of charged droplets is formed. To avoid contamination, this capillary is usually perpendicularly located at the inlet of the MS system. The heat created by the electric potential is used to rapidly evaporate the droplets in an atmosphere of dry nitrogen. Later, the ionized analytes are transferred into the high vacuum chamber of the MS as the charged ions flow through a series of small apertures with the aid of focusing voltages. Positively and negatively charged ions can be detected and it is possible to switch between the negative and positive modes of operation. Most ions produced in the ESI interface are multiply charged. The use of 1–3 mm ID microbore columns is recommended for LC-MS systems using electrospray ionization (ESI) interfaces because optimal operation is achieved with flow rates in the 50-200 μl/min range.


title: Liquid chromatography–mass spectrometry

text: The development of the APCI interface for LC-MS started with Horning and collaborators in the early 1973. However, its commercial application was introduced at the beginning of the 1990s after Henion and collaborators improved the LC-APCI-MS interface in 1986. The APCI ion source/ interface can be used to analyze small, neutral, relatively non-polar, and thermally stable molecules (e.g., steroids, lipids, and fat soluble vitamins). These compounds are not well ionized using ESI. In addition, APCI can also handle mobile phase streams containing buffering agents. The liquid from the LC system is pumped through a capillary and there is also nebulization at the tip, where a corona discharge takes place. First, the ionizing gas surrounding the interface and the mobile phase solvent are subject to chemical ionization at the ion source. Later, these ions react with the analyte and transfer their charge. The sample ions then pass through small orifice skimmers by means of or ion-focusing lenses. Once inside the high vacuum region, the ions are subject to mass analysis. This interface can be operated in positive and negative charge modes and singly-charged ions are mainly produced. APCI ion source can also handle flow rates between 500 and 2000 μl/min and it can be directly connected to conventional 4.6 mm ID columns.


title: Liquid chromatography–mass spectrometry

text: The APPI interface for LC-MS was developed simultaneously by Bruins and Syage in 2000. APPI is another LC-MS ion source/ interface for the analysis of neutral compounds that cannot be ionized using ESI. This interface is similar to the APCI ion source, but instead of a corona discharge, the ionization occurs by using photons coming from a discharge lamp. In the direct-APPI mode, singly charged analyte molecular ions are formed by absorption of a photon and ejection of an electron. In the dopant-APPI mode, an easily ionizable compound (Dopant) is added to the mobile phase or the nebulizing gas to promote a reaction of charge-exchange between the dopant molecular ion and the analyte. The ionized sample is later transferred to the mass analyzer at high vacuum as it passes through small orifice skimmers.


title: Liquid chromatography–mass spectrometry

text: The coupling of MS with LC systems is attractive because liquid chromatography can separate delicate and complex natural mixtures, which chemical composition needs to be well established (e.g., biological fluids, environmental samples, and drugs). Further, LC-MS has applications in volatile explosive residue analysis. Nowadays, LC-MS has become one of the most widely used chemical analysis techniques because more than 85% of natural chemical compounds are polar and thermally labile and GC-MS cannot process these samples. As an example, HPLC-MS is regarded as the leading analytical technique for proteomics and pharmaceutical laboratories. Other important applications of LC-MS include the analysis of food, pesticides, and plant phenols.


title: Liquid chromatography–mass spectrometry

text: LC-MS is widely used in the field of bioanalysis and is specially involved in pharmacokinetic studies of pharmaceuticals. Pharmacokinetic studies are needed to determine how quickly a drug will be cleared from the body organs and the hepatic blood flow. MS analyzers are useful in these studies because of their shorter analysis time, and higher sensitivity and specificity compared to UV detectors commonly attached to HPLC systems. One major advantage is the use of tandem MS-MS, where the detector may be programmed to select certain ions to fragment. The measured quantity is the sum of molecule fragments chosen by the operator. As long as there are no interferences or ion suppression in LC-MS, the LC separation can be quite quick.


title: Liquid chromatography–mass spectrometry

text: LC-MS is used in proteomics as a method to detect and identify the components of a complex mixture. The bottom-up proteomics LC-MS approach generally involves protease digestion and denaturation using trypsin as a protease, urea to denature the tertiary structure, and iodoacetamide to modify the cysteine residues. After digestion, LC-MS is used for peptide mass fingerprinting, or LC-MS/MS (tandem MS) is used to derive the sequences of individual peptides. LC-MS/MS is most commonly used for proteomic analysis of complex samples where peptide masses may overlap even with a high-resolution mass spectrometry. Samples of complex biological (e.g., human serum) may be analyzed in modern LC-MS/MS systems, which can identify over 1000 proteins. However, this high level of protein identification is possible only after separating the sample by means of SDS-PAGE gel or HPLC-SCX. Recently, LC-MS/MS has been applied to search peptide biomarkers. An example is the recent discovery and validation of peptide biomarkers for four major bacterial respiratory tract pathogens ("Staphylococcus aureus," "Moraxella catarrhalis"; "Haemophilus influenzae" and "Streptococcus pneumoniae").


title: Liquid chromatography–mass spectrometry

text: LC-MS has emerged as one of the most commonly used techniques in global metabolite profiling of biological tissue (e.g., blood plasma, serum, urine). LC-MS is also used for the analysis of natural products and the profiling of secondary metabolites in plants. In this regard, MS-based systems are useful to acquire more detailed information about the wide spectrum of compounds from a complex biological samples. LC-Nuclear magnetic resonance (NMR) is also used in plant metabolomics, but this technique can only detect and quantify the most abundant metabolites. LC-MS has been useful to advance the field of plant metabolomics, which aims to study the plant system at molecular level providing a non-biased characterization of the plant metabolome in response to its environment. The first application of LC-MS in plant metabolomics was the detection of a wide range of highly polar metabolites, oligosaccharides, amino acids, amino sugars, and sugar nucleotides from "Cucurbita maxima" phloem tissues. Another example of LC-MS in plant metabolomics is the efficient separation and identification of glucose, sucrose, raffinose, stachyose, and verbascose from leaf extracts of "Arabidopsis thaliana".


title: Liquid chromatography–mass spectrometry

text: LC-MS is frequently used in drug development because it allows quick molecular weight confirmation and structure identification. These features speed up the process of generating, testing, and validating a discovery starting from a vast array of products with potential application. LC-MS applications for drug development are highly automated methods used for peptide mapping, glycoprotein mapping, lipodomics, natural products dereplication, bioaffinity screening, "in vivo" drug screening, metabolic stability screening, metabolite identification, impurity identification, quantitative bioanalysis, and quality control.


title: Shades of violet

text: Violet is a color term derived from the flower of the same name. There are numerous variations of the color violet, a sampling of which are shown below.


title: Shades of violet

text: The term violet has different meanings in different languages, countries and epochs. Even among many modern speakers within the English-speaking world there is confusion about the terms purple and violet. The blue-dominated spectral color beyond blue is referred to as purple by many speakers in the United States, but this color is called violet by many speakers in the United Kingdom. In some British authoritative texts the term purple refers to any mixture of red and blue, suggesting the color term purple covers the full range between red and blue in the United Kingdom. In other texts it is the term violet that covers the same full range of colors.


title: Shades of violet

text: The uncertainty about the range of meanings of the color terms violet and purple is even larger when other languages and historical texts are considered.


title: Shades of violet

text: Although pure spectrum violet is outside the color gamut of the RGB color space, the three colors displayed below are rough approximations of the range of colors of actual spectral violet, although the accuracy of the approximation can vary depending on the individual's color vision, and on the color rendition of one's computer monitor.


title: Shades of violet

text: The tertiary color on the HSV color wheel (also known as the ) precisely halfway between blue and magenta is called color wheel violet. This tone of violet—an approximation of the color violet at about 417 nanometers as plotted on the CIE chromaticity diagram—is shown at right. This tone of violet is actually somewhat toward indigo assuming indigo is accepted as a separate spectrum color, usually quoted as having a range of from about 420 to 450 nanometers. Another name for this color is near violet.


title: Shades of violet

text: The color at right, electric violet, is the closest approximation to middle "spectrum violet" that can be made on a computer screen, given the limitations of the sRGB color gamut. It is an approximation of the color violet at about 400 nanometers as plotted on the CIE chromaticity diagram, in the middle of the violet range of from 380 nanometers to 420 nanometers, assuming indigo as a separate spectrum color from 420 to 450 nanometers. Other names for this color are middle violet or simply violet.


title: Shades of violet

text: Displayed at right is the color vivid violet, a color approximately equivalent to the violet seen at the extreme edge of human visual perception. When plotted on the CIE chromaticity diagram, it can be seen that this is a hue corresponding to that of a visual stimulus of approximately 380 nm on the spectrum. Thus another name for this color is extreme violet.


title: Shades of violet

text: The so-called web color "violet" is in actuality not really a tint of violet, a spectral color, but is a non-spectral color. The web color violet is actually a rather pale tint of magenta because it has equal amounts of red and blue (the definition of magenta for computer display), and some of the green primary mixed in, unlike most other variants of violet that are closer to blue. This same color appears as "violet" in the X11 color names.


title: Shades of violet

text: The color box at right displays the web color dark violet which is equivalent to pigment violet, i.e., the color violet as it would typically be reproduced by artist's paints, colored pencils, or crayons as opposed to the brighter "electric" violet above that it is possible to reproduce on a computer screen.


title: Shades of violet

text: Compare the subtractive colors to the additive colors in the two primary color charts in the article on primary colors to see the distinction between electric colors as reproducible from light on a computer screen (additive colors) and the pigment colors reproducible with pigments (subtractive colors); the additive colors are a lot brighter because they are produced from light instead of pigment.


title: Shades of violet

text: Pigment violet (web color dark violet) represents the way the color violet was always reproduced in pigments, paints, or colored pencils in the 1950s.


title: Shades of violet

text: By the 1970s, because of the advent of psychedelic art, artists became used to brighter pigments, and pigments called "Violet" that are the pigment equivalent of the electric violet reproduced in the section above became available in artists pigments and colored pencils. (When approximating electric violet in artists pigments, a bit of white pigment is added to pigment violet.)


title: Shades of violet

text: The source of this color is the "Pantone Textile Paper eXtended (TPX)" color list, color #18-3838 TPX—Ultra Violet.


title: Shades of violet

text: The source of this color is the "Pantone Textile Paper eXtended (TPX)" color list, color #16-3250 TPX—African Violet.


title: Shades of violet

text: The source of this color is the "Pantone Textile Paper eXtended (TPX)" color list, color #18-3418 TPX—Chinese Violet.


title: Shades of violet

text: At right is displayed the color French violet, which is the tone of violet that is called "violet" in the Pourpre.com color list, a color list widely popular in France.


title: Shades of violet

text: This is the color called "violet" in the traditional Japanese colors group, a group of colors in use since beginning in 660 CE in the form of various dyes


title: Shades of violet

text: Spanish violet is the color that is called "Violeta" (the Spanish word for "violet") in the "Guía de coloraciones" ("Guide to colorations") by Rosa Gallego and


title: Shades of violet

text: Juan Carlos Sanz, a color dictionary published in 2005 that is widely popular in the Hispanophone realm.


title: Shades of violet

text: It is currently unknown when "grape" was first used as a color name in English, but in 1994, "grape" was made into one of the Crayola Magic Scent crayon colors.


title: Shades of violet

text: At right is displayed the color lavender. This color may also be called lavender (floral) or floral lavender to distinguish it from the web color lavender. It is the color of the central part of the lavender flower.


title: Shades of violet

text: Mauve (from the French form of "Malva" "mallow") is a color that is named after the mallow flower. Another name for the color is mallow with the first recorded use of "mallow" as a color name in English in 1611.


title: Shades of violet

text: It represents the color of wisteria blooms. A crayon of this color and name was formulated by Crayola in 1993.


title: The Flash (season 1)

text: The first season of the American television series "The Flash" premiered on The CW on October 7, 2014, and concluded on May 19, 2015, after airing 23 episodes. The series is based on the DC Comics character Barry Allen / Flash, a costumed superhero crime-fighter with the power to move at superhuman speeds. It is a spin-off from "Arrow", existing in the same fictional universe, and was produced by Berlanti Productions, Warner Bros. Television, and DC Entertainment, with Andrew Kreisberg serving as showrunner.


title: The Flash (season 1)

text: The series follows Allen, portrayed by Grant Gustin, a crime scene investigator who gains super-human speed, which he uses to fight criminals, including others who have also gained superhuman abilities. Gustin is joined by main cast members Candice Patton, Danielle Panabaker, Rick Cosnett, Carlos Valdes, Tom Cavanagh, and Jesse L. Martin. "The Flash" was picked up for a full season by The CW in October 2014, and filming took place primarily in Vancouver, British Columbia, Canada.


title: The Flash (season 1)

text: The series premiere was watched by 4.8 million viewers and had a 1.9 18–49 demographic rating, making it The CW's most watched and highest rated series premiere since "The Vampire Diaries" in 2009. It also became The CW's second-most watched series premiere ever, behind "90210", and the third-highest rated in the 18–49 demographic. The first season finished as the 118th ranked show, with an average viewership of 4.62 million, making it the most watched series ever on The CW, and also the highest rated series among men 18–49 and men 18+ ever on the network. The first season of "The Flash" received generally positive reviews from critics. Reviews for the series became increasingly positive as the season progressed, with the finale receiving critical acclaim. The series was renewed for a second season on January 11, 2015.


title: The Flash (season 1)

text: On July 30, 2013, it was announced that "Arrow" co-creators Greg Berlanti and Andrew Kreisberg, "Arrow" pilot director David Nutter, and DC Comics CCO Geoff Johns would develop a television series based on the Flash for The CW, and it would detail Barry Allen's origin. Kreisberg revealed after the announcement that Allen would first appear as a recurring character on "Arrow" in three episodes of season two—all written by Berlanti, Kreisberg and Johns—and the last of the episodes would act as a backdoor pilot for the new show. Kreisberg added that Allen would be a forensic scientist and the introduction of his superpowers, as well as the reactions to this, will be very human and grounded. Johns stated that the character of the Flash in the show would resemble his comic book counterpart, complete with his trademark red costume, and not be a poor imitation. Kreisberg elaborated: "No sweat suits or strange code names; he "will be" The Flash." While researching the best way to depict the Flash's lightning speed, Johns stated it would not just be the standard "blurring around".


title: The Flash (season 1)

text: Barry ultimately appeared twice in "Arrow"s second season, with the planned backdoor pilot canceled in favor of a traditional pilot by The CW executives, who had been impressed by early cuts of Barry's first two episodes on "Arrow". This allowed the creative team to flesh out Barry's story and his world on a bigger budget, as opposed to a backdoor pilot's constraint of incorporating characters from the parent show. The pilot was officially ordered on January 29, 2014, and was written by Berlanti, Kreisberg, and Johns, and directed by Nutter. On May 8, 2014, "The Flash" was officially picked up as a series, with an initial order of 13 episodes. Three more scripts were ordered in September 2014 following a positive response to newly completed episodes by executives, while a back ten was ordered on October 21, 2014, for a full 23-episode season.


title: The Flash (season 1)

text: In July 2014, Johns described the series as "the most faithful DC Comics adaptation ever... We've incorporated almost everything of the mythology into it and added a new backstory with S.T.A.R. Labs." In October 2014, Johns explained that DC's approach to their films and television series would be different from Marvel Studios' cinematic universe, stating that their film universe and TV universes would be kept separate within a multiverse to allow "everyone to make the best possible product, to tell the best story, to do the best world."


title: The Flash (season 1)

text: On September 13, 2013, Grant Gustin was cast in the titular role of Barry Allen / Flash. Andy Mientus, who would eventually be cast as Hartley Rathaway, also auditioned for the role. Gustin began researching the character during the audition process, and reading as many comics as possible. Gustin primarily focused on The New 52 series of comics, because he knew it would be difficult to read everything and he felt the New 52 was the closest to the show's "look and feel". In January 2014, actor Jesse L. Martin was cast as Detective Joe West, while Rick Cosnett was cast as Eddie Thawne and Danielle Panabaker as Caitlin Snow. In February 2014, Candice Patton was cast as Iris West and Carlos Valdes as Cisco Ramon. Patton's casting as Iris caused significant backlash among comic book fans due to Patton being of African descent, while Iris has typically been depicted as a Caucasian woman in comics. Though the writers discussed early on to make Barry and Caitlin lovers, Gustin vetoed this idea in favour of Barry and Iris, as in the comics. Also in February 2014, "The Hollywood Reporter" reported that the remaining regular roles to be cast were for the parts of Harrison Wells and Hartley Rathaway. On February 10, 2014, Tom Cavanagh was cast as Harrison Wells, with his role described as "a rock star in the world of physics and the mind and money behind Central City's S.T.A.R. Labs Particle Accelerator". It was eventually revealed that Cavanagh's character was actually Eobard Thawne, who stole the appearance of the real Wells (also portrayed by Cavanagh) after killing him, with Matt Letscher portraying Thawne's original likeness.


title: The Flash (season 1)

text: Several cast members from the 1990 television series appear in the series. John Wesley Shipp, who portrayed Barry Allen/Flash in the 1990 series, joined the cast in a recurring role as Barry's father, Dr. Henry Allen, and Amanda Pays once again portrays a character named Dr. Tina McGee. In the episode "Tricksters", Mark Hamill returns as James Jesse / Trickster and Vito D'Ambrosio plays Mayor Anthony Bellows (a character he played in 1991, but as a police officer), with images of Hamill as Trickster from the 1990 TV series being used in a police report.


title: The Flash (season 1)

text: The Flash costume was designed by Colleen Atwood. While remaining largely faithful to Barry's costume from the comics, it was designed as a more "functional, textured quality" costume than previous live-action Flash ones.


title: The Flash (season 1)

text: Production on the pilot began in March 2014, with filming taking place in Vancouver, British Columbia; additional filming for the series takes place in Portland, Oregon. On how action sequences are shot for the series, compared to "Arrow", Gustin said, "When ["Arrow"] shoot[s] action sequences, pretty much what you see is what you get and they're really doing everything. We do a lot of plate shots that are empty shots of the area we’re going to be in and then they’re putting us in later in post. I do a lot of the fighting. I don’t have to do it full speed and then they ramp it up and a lot of people have to freeze and I keep moving. Then I have to clear frame and step back into frame. It’s really tedious stuff that we have to do. On theirs, they learn fight choreography and they shoot it from the perfect angles and what you see is what you get."


title: The Flash (season 1)

text: "Arrow" composer Blake Neely is the primary composer of the series, and was first hired in April 2014 to score the pilot. He had previously composed a theme for Barry Allen which was featured in "Arrow"s season two episodes "The Scientist" and "Three Ghosts". The theme was titled "The Scientist" when it was released on the "Arrow: Season 2" soundtrack. According to Neely, "It had to be different [from "Arrow"] ... but it also couldn't be so different that it couldn't fit in the "Arrow" universe, ... it had to be in a style that could hold hands with "Arrow"." On December 18, 2014, WaterTower Music released a selection of music from "The Flash"/"Arrow" crossover episodes, as well as two bonus tracks from their respective 2014 midseason finales. The first season, two-disc soundtrack was released on October 16, 2015 by La La Land Records.


title: The Flash (season 1)

text: In March 2014, it was announced that Gustin would not appear in a third episode of "Arrow" as originally planned. However, Panabaker and Valdes appear in the "Arrow" episode "The Man Under the Hood" in their roles as Caitlin Snow and Cisco Ramon, respectively. "Arrow" executive producer Marc Guggenheim stated, "This was something that really came about because obviously Barry is in a coma at the end of ["Three Ghosts"]. That pretty much made it impossible for Barry to appear in [the third episode, as originally planned]... The idea of bringing in [Caitlin Snow and Cisco Ramon] really, really appealed to us because it allowed us to honor our original intention [of] doing something Flash-related around episode 19 or 20 [of season two] without having comatose Barry and basically paying Grant Gustin a lot of money to sit around with his eyes closed just unconscious the whole episode... It allows us to further flesh out the "Flash" universe in "Arrow"." Gustin had a brief cameo appearance in the "Arrow" season three premiere, "The Calm". Valdes appeared once again in the season three episode "Broken Arrow", while Gustin appeared in the final episode of season three, "My Name is Oliver Queen".


title: The Flash (season 1)

text: Stephen Amell appears as Oliver Queen / Arrow in the pilot episode. Kreisberg announced that Emily Bett Rickards would appear in the fourth episode as Felicity. Previous "Arrow" adversary William Tockman / The Clock King (Robert Knepper) was in the seventh episode. Members of The Royal Flush Gang, who previously appeared on "Arrow", made a cameo appearance in the eleventh episode of the series. Rickards and Brandon Routh as Ray Palmer had scenes in the eighteenth episode, "All Star Team Up". Katie Cassidy and Paul Blackthorne, as Laurel Lance / Black Canary and Detective Quentin Lance, respectively, appeared in the following episode, "Who Is Harrison Wells?", while Amell and Doug Jones as Jake Simmons / Deathbolt appeared in the twenty-second episode, "Rogue Air".


title: The Flash (season 1)

text: On July 18, 2014, Kreisberg stated that a crossover event would occur in the eighth episode of the first season of "The Flash" and the third season of "Arrow", respectively. In early January 2015, The CW president Mark Pedowitz announced the intention to do a "Flash"/"Arrow" crossover every season, after the success of the first one.


title: The Flash (season 1)

text: In April 2015, to celebrate the season three finale of "Arrow" and season one finale of "The Flash", The CW released a short promo titled "Superhero Fight Club". The short features characters from "Arrow" and "The Flash" battling each other in a hero vs. villain showdown. Characters include Arrow, Flash, Arsenal, Black Canary, Merlyn, Captain Cold, Heat Wave, Firestorm, Ra's al Ghul, Reverse-Flash, and the A.T.O.M. in a cage match fight.


title: The Flash (season 1)

text: "The Flash" was screened at the Warner Bros. Television and DC Entertainment panel at San Diego Comic-Con International in July 2014. The series officially premiered on The CW on October 7, 2014, during the 2014–15 television season and also premiered in Canada on the same night. The second episode was screened at New York Comic Con on October 9, 2014, as a way to repay the viewers that watched the series' premiere episode. The series premiered in the United Kingdom and Ireland on October 28, 2014, and in Australia on December 3, 2014.


title: The Flash (season 1)

text: The season began streaming on Netflix on October 6, 2015, and was released on Blu-ray and DVD in Region 1 on September 22, 2015.


title: The Flash (season 1)

text: The first episode of "The Flash" was watched by 4.8 million viewers and had a 1.9 18–49 demographic rating, making it The CW's most watched and highest rated series premiere since "The Vampire Diaries" in 2009. It also became The CW's second-most watched series premiere ever, behind "90210", and the third-highest rated in the 18–49 demographic. Factoring Live + 7 day ratings, the pilot was watched by a total of 6.8 million viewers, becoming The CW's most-watched telecast and the highest-rated premiere among men 18–34 (2.5 rating). It broke the previous record for the most-watched telecast held by the cycle 8 finale of "America's Next Top Model" in 2007 (6.69 million). Additionally, across all platforms, including initiated streams on digital platforms and total unduplicated viewers on-air over two airings the week of October 7, 2014, the premiere was seen more than 13 million times.


title: The Flash (season 1)

text: The Canadian premiere was watched by 3.11 million viewers, making it the most-watched broadcast that night and the second for that week. In the United Kingdom, the premiere was the fourth highest-rated broadcast of the week and the eleventh of that month, with 1.53 million viewers. The timeshifted version got 82,000 viewers. The premiere in Australia was the most-watched broadcast on pay television, with 129,000 viewers tuning in.


title: The Flash (season 1)

text: The first season finished as the 118th ranked show, with an average viewership of 4.62 million, helping to deliver The CW's most watched season in seven years. "The Flash" finished the season as the most watched series ever on The CW with 5.85 million viewers, and also the highest rated series among men 18–49 (2.8 rating) and men 18+ ever on the network.


title: The Flash (season 1)

text: Season 1 of "The Flash" received generally positive reviews from critics. The review aggregator website Rotten Tomatoes reported a 92% approval rating with an average rating of 7.75/10 based on 63 reviews. The website's consensus reads, ""The Flash" benefits from its purposefully light atmosphere, making it a superhero show uniquely geared toward genre fans as well as novices." Metacritic, which uses a weighted average, assigned a score of 73 out of 100, based on 27 reviews, indicating "generally favorable reviews".


title: The Flash (season 1)

text: IGN's Eric Goldman and Joshua Yehl praised the show's premise and cast after viewing a press screening copy of the pilot. Goldman and Yehl favorably compared it to "Arrow", stating that "The Flash" progresses with a confidence that "Arrow" did not get until later in the series. Reviews for the series became increasingly positive as the season progressed, with the finale receiving critical acclaim.


title: The Flash (season 1)

text: Noel Murray of The A.V. Club gave the season a B+ overall, giving praise to the pacing of the plot, the performances of the cast and the special effects, and also pointing out the series' boldness to embrace its comic book influences, something that conventional superhero shows tend not to do. Weekly episode reviewer Scott Von Doviak gave consistently high ratings to the season and awarded the season finale a perfect A grade, calling the episode "richly satisfying" and also commending the show for "[capturing] the essence of its source material in a fun, light-on-its-feet way that few other comic book adaptations have managed." He also gave high praise to the emotional value and performances of the cast, as well as the cliffhanger and multiple easter eggs found in the episode.


title: The Flash (season 1)

text: "The Flash" was included on multiple Best/Top TV Shows of 2014 lists, ranking on "NPR" and "Omaha World-Herald"s (7th), and "Film School Rejects" (10th). In its first season, "The Flash" was nominated for 35 awards, including an Emmy nomination for Outstanding Special Visual Effects for the episode "Grodd Lives", and winning nine. The show was nominated for four Saturn Awards, winning Best Superhero Adaption Television Series and Wentworth Miller winning for Best Guest Star on Television. Gustin was honored with the Breakthrough Performance Saturn Award at the ceremony for his electrifying performance as Barry Allen/The Flash. The series received eight Leo Awards nominations, including Best Dramatic Series and winning Best Visual Effects in a Dramatic Series for the episode "Going Rogue". It also won the People's Choice Award for "Favorite New TV Drama" for the 2014–15 season. "The Atlantic" named the season finale, "Fast Enough" one of the best television episodes of 2015.


title: How Heavy Are the Dumbbells You Lift?

text: Hibiki Sakura is a second-year high school girl who has a voracious appetite; this habit leads to her gaining weight. Once this is brought to her attention, she reluctantly thinks about joining the Silverman Gym. At the gym, Hibiki finds out that Akemi Soryuin, a schoolmate of hers, is also thinking about joining. Upon meeting Naruzo Machio, one of the trainers, she falls heads over heels in love with him and joins the gym. Motivated, Hibiki vows to lose weight.


title: How Heavy Are the Dumbbells You Lift?

text: "How Heavy Are the Dumbbells You Lift?" is written by Yabako Sandrovich and illustrated by MAAM. The series is set in the same universe as Sandrovich's other work "Kengan Ashura". It began serialization on Shogakukan's "Ura Sunday" website and "MangaONE" app on August 5, 2016. Shogakukan has compiled its chapters into individual "tankōbon" volumes. The first volume was published on December 19, 2016. As of December 19, 2022, seventeen volumes have been published. In North America, Seven Seas Entertainment announced the acquisition of the manga for an English release in April 2019. The first volume was published on November 26, 2019.


title: How Heavy Are the Dumbbells You Lift?

text: An anime television series adaptation was announced on January 15, 2019. The series was produced by Doga Kobo and directed by Mitsue Yamazaki, with Fumihiko Shimo handling the series composition, Ai Kikuchi designing the characters, and Yukari Hashimoto composing the music. It aired from July 3 to September 18, 2019 on AT-X, Tokyo MX, KBS, SUN, and other channels. It ran for 12 episodes. The opening theme is performed by Fairouz Ai and Kaito Ishikawa, while the ending theme is performed by Ishikawa.


title: How Heavy Are the Dumbbells You Lift?

text: Funimation had licensed the series outside Asia. Following Sony's acquisition of Crunchyroll, the series was moved to Crunchyroll. Medialink holds the license for the series in Southeast Asia.


title: How Heavy Are the Dumbbells You Lift?

text: "Gadget Tsūshin" listed lines from the opening theme and the training video in their 2019 anime buzzwords list.


title: How Heavy Are the Dumbbells You Lift?

text: The anime series was nominated for Best Boy for Naruzo Machio and Best Comedy at the 4th Crunchyroll Anime Awards, but lost to Tanjiro Kamado from "" and "", respectively.


title: Western Xia

text: The Western Xia or the Xi Xia (), officially the Great Xia (), also known as the Tangut Empire, and known as "Mi-nyak" to the Tanguts and Tibetans, was a Tangut-led Buddhist imperial dynasty of China that existed from 1038 to 1227. At its peak, the dynasty ruled over the modern-day northwestern Chinese provinces of Ningxia, Gansu, eastern Qinghai, northern Shaanxi, northeastern Xinjiang, and southwest Inner Mongolia, and southernmost Outer Mongolia, measuring about . Its capital was Xingqing (modern Yinchuan), until its destruction by the Mongols in 1227. Most of its written records and architecture were destroyed, so the founders and history of the empire remained obscure until 20th-century research in China and the West.


title: Western Xia

text: The Western Xia occupied the area around the Hexi Corridor, a stretch of the Silk Road, the most important trade route between northern China and Central Asia. They made significant achievements in literature, art, music, and architecture, which was characterized as "shining and sparkling". Their extensive stance among the other empires of the Liao, Song, and Jin was attributable to their effective military organizations that integrated cavalry, chariots, archery, shields, artillery (cannons carried on the back of camels), and amphibious troops for combat on land and water.


title: Western Xia

text: The full title of the Western Xia as named by their own state is reconstructed as /*phiow¹-bjij²-lhjij-lhjij²/, which word by word denotes "white", "high", "kingdom", "great", or , "white", "high", "great", "summer", "kingdom". The corresponding Chinese name, ("White High Great Xia State"), was also used. Chinese and Japanese scholars commonly interpret the first two words as "upper reaches of the White River", which was possibly referring to the Yellow River. Kepping (1994) proposed the translation "the Kingdom of the Great Xia of the White and Lofty", and suggested that the name refers to a peak in the Helan Mountains named the "White and Lofty Mother". The region was known to the Tanguts as /mjɨ-njaa/, and to the Tibetans as Minyak. Another name the Tanguts used for their state was /khjɨ-dwuu-lhjij/ (), which means the "State of Ten Thousand Secrets". "Western Xia" or "Xi Xia" is the state's Chinese name. "Western" refers to its location to the west of the Liao (916–1125) and Jin (1115–1234) dynasties, as well as the Song. "Xia" (pointing to the Xia dynasty) is a historical name for the region that originated from the 5th-century Hu Xia dynasty.


title: Western Xia

text: The name Tangut is derived from a form first found in the Orkhon inscriptions dated to 735, which is transcribed in Chinese as Tangwu or Tangute ("Tangghut" ("Tangɣud") in Mongolian). Tangut was used a common name for certain tribes in the Amdo-Kokonor-Gansu region until the 19th century. The Tanguts called themselves Minag, transcribed in Chinese as Mianyao or Miyao.


title: Western Xia

text: The Tanguts originally came from the Tibet-Qinghai region. According to Chinese records, which called them the Dangxiang, the Tanguts were descended from the Western Qiang people, and occupied the steppes around Qinghai Lake and the mountains to its south.


title: Western Xia

text: In 608, the Tanguts helped the Sui dynasty defeat the Tuyuhun, however they were betrayed by the Sui forces, who took the chance to loot the Tanguts. In 635, they were requested to serve as guides for Emperor Taizong's campaign against Tuyuhun, but the Tang forces double crossed them in a surprise attack and seized thousands of livestock. In retaliation, the Tanguts attacked the Tang and killed thousands of their soldiers.


title: Western Xia

text: By the 650s, the Tanguts had left their homeland to escape pressure from the Tibetans and migrated eastward to what are now modern Shanxi and Shaanxi provinces. In 584-5 Tuoba Ningzong led the first group of Tanguts to submit to the Sui. In 628-9 another group under the leadership of Xifeng Bulai surrendered to the Tang. After the Tuyuhun were defeated in 635, the Tanguts under Tuoba Chici also surrendered. The 340,000 Tanguts were divided into 32 "jimi" prefectures under the control of Tangut chieftains appointed as prefects. Another wave of Tanguts entered Tang territory in 692, adding as many as 200,000 persons to the population in Lingzhou and Xiazhou. In 721-2, Tuoba Sitai, a descendant of Tuoba Chici, aided the Tang in putting down a Sogdian-led revolt in Shuofang. By the time of the An Lushan Rebellion in the 750s, the Tanguts had become the primary local power in the Ordos region in northern Shaanxi. In the 760s, the military commander, Ashina Sijian, harassed six Tangut tribes and took their camels and horses. The Tanguts fled west across the Yellow River and started working for the Tibetans as guides on raiding expeditions. In 764, the Tanguts joined the Tibetans and Uyghurs in supporting the Tang rebel Pugu Huaien. After the Tang reasserted their authority, a descendant of Tuoba Chici, Tuoba Chaoguang, was put in charge of the loyal Tanguts. The Yeli, Bali, and Bozhou clans continued to side with the Tibetans, however the Tanguts also came under Tibetan predation, and frontier settlements continued switching between Tang and Tibetan control for many years. In 806, the Acting Minister of Works, Du You, admitted that they treated the Tanguts badly:


title: Western Xia

text: In 814 the Tang appointed a Commissioner for Pacifying the Tanguts to Youzhou (modern Otog Banner), however this did not resolve the Tangut problem. In 820 the Tanguts were subjected to the tyranny of a local governor, Tian Jin. They retaliated by joining the Tibetans in raids on Tang garrisons. Sporadic conflict with the Tanguts lasted until the 840s when they rose in open revolt against the Tang, but the rebellion was suppressed. Eventually the Tang court was able to mollify the Tanguts by admonishing their frontier generals and replacing them with more disciplined ones. The Tanguts also fought against the Uyghurs after the collapse of the Uyghur Khaganate because they both wanted to monopolize the horse trade which passed through Lingzhou.


title: Western Xia

text: In 873, the senior Tangut leader at Xiazhou, Tuoba Sigong, occupied Youzhou and declared himself prefect. When Chang'an fell to Huang Chao in 880, Sigong led a Chinese-Tangut army to assist Tang forces in driving out the rebels. For his service, he was granted in 881 control of Xiazhou, Youzhou, Suizhou, Yinzhou, and later also Jingbian. Together the territory was called Dingnan Jiedushi, also known as Xiasui, centered on modern Yulin, Shaanxi. After the Huang Chao rebellion's defeat in 883, Sigong was granted the dynastic surname Li and enfeoffed as "Duke of Xia". In 878, the Shatuo chieftain Li Guochang attacked the Tanguts but was repelled by a Tuyuhun intervention.


title: Western Xia

text: Sigong died in 886 and was succeeded by his brother Sijian. In 905 Li Keyong's independent regime allied with the Khitans, which pushed the Tanguts into an alliance with Later Liang, which awarded the Dingnan rulers with honorary titles. Sijian died in 908 and was succeeded by his adopted son Yichang, who was murdered by his officer Gao Zongyi in 909. Gao Zongyi was himself murdered by soldiers of Dingnan and was replaced by Yichang's uncle, Renfu, who was a popular officer in the army. In 910 Dingnan came under a monthlong siege by the forces of Qi and Jin but was able to repel the invasion with the aid of Later Liang. In 922 Renfu sent 500 horses to Luoyang, perhaps to aid the Later Liang in fighting the Shatuo. In 924 Renfu was enfeoffed as "Prince of Shuofang" by Later Tang. When Renfu died in 933, Later Tang tried to replace his son, Yichao, with a Sogdian governor, An Congjin. An Congjin besieged Xiazhou with 50,000 soldiers, but the Tanguts mounted a successful defensive by rallying the tribes and stripping the countryside of any resources. The Later Tang army was forced to retreat after three months. Despite Later Tang aggression, Yichao made peace with them by sending 50 horses as an offering.


title: Western Xia

text: Yichao died in 935 and was succeeded by his brother Yixing. Yixing discovered a plot by his brother, Yimin, to overthrow him in 943. Yimin fled to Chinese territory, but was returned to Xiazhou for execution. Over 200 clan members were implicated in the plot, resulting in a purge of the core ranks. Yimin's post was taken by a loyal official, Renyu. Not long afterward, Renyu was killed by the Yemu Qiang, who departed for Chinese territory. In 944 Yixing may have attacked the Liao dynasty on behalf of the Later Jin. The sources are not clear on the event. In 948 Yixin requested permission to cross the border and attack the Yemu Qiang but was refused. Instead Yixing attacked a neighboring circuit under encouragement from the rebel Li Shouzhen, but retreated upon encountering an imperial force. In 952 the Yeji people north of Qingzhou rebelled, causing the Tanguts significant difficulty. Honorary titles were given out by the Later Han to appease local commanders, including Yixing. In 960 Dingnan came under attack by Northern Han and successfully repelled invading forces. In 962 Yixing offered horses as tribute to the Song dynasty. Yixing died in 967 and was succeeded by his son, Kerui.


title: Western Xia

text: Kerui died in 978 and was succeeded by Jiyun. Jiyun ruled for only a year before dying in 980. His son was still an infant, so Jiyun's brother, Jipeng, assumed leadership. Jipeng did not go through the traditional channel of acquiring consent from the elders, which caused dissent among the Tangut elites. The Tangut prefect of Suizhou challenged Jipeng's succession. In 982 Jipeng fled to the Song court and surrendered control of Dingnan Jiedushi. His brother or cousin, Jiqian, did not agree to this and refused to submit to Song administration. Jiqian led a group of bandit holdouts and resisted Song control. In 984, the Song attacked his camp and captured his mother and wife, but he narrowly escaped. He rebounded from this defeat by capturing Yinzhou the next year. Along with Yinzhou, Jiqian captured large amounts of supply, allowing him to increase his following. In 986, Jiqian submitted to the Khitans and in 989, Jiqian married into Khitan nobility. Jiqian also made symbolic obeisance to the Song, but the Song remained unconvinced of his intentions. Jipeng was sent by the Song to destroy Jiqian, but he was defeated in battle on 6 May 994, and fled back to Xiazhou. Jiqian sent tribute on 9 September as well as his younger brother on 1 October to the Song court. Emperor Taizong of Song was receptive of these gestures, but Jiqian returned to raiding Song territory the next year. In April 996, Taizong sent troops to suppress Jiqian, who raided Lingzhou in May and again in November 997. For a brief period after 998, Jiqian accepted Song suzerainty, until the fall of 1001 when he began raiding again. Jiqian died on 6 January 1004 from an arrow wound. His son and successor, Deming, proved to be more amicable towards the Song than his predecessor.


title: Western Xia

text: Deming sent tribute missions to both the Liao dynasty and the Song dynasty. At the same time he expanded Tangut territory to the west. In 1028, he sent his son Yuanhao to conquer the Ganzhou Uyghur Kingdom. Two years later the Guiyi Circuit surrendered to the Tanguts. Yuanhao invaded the Qinghai region as well but was repelled by the newly risen Tibetan kingdom of Tsongkha. In 1032, Yuanhao annexed the Tibetan confederation of Xiliangfu, and soon after his father died, leaving him ruler of the Tangut state.


title: Western Xia

text: Upon his father's death, Yuanhao adopted the Tangut surname of Weiming (Tangut: Nweimi) for his clan. He levied all able bodied men between 15 and 60 years of age, providing him with a 150,000 strong army. By 1036, he had annexed both the Ganzhou Uyghur Kingdom and the Guiyi Circuit to his west. In the same year, the Tangut script was disseminated for use in the Tangut government and translations of Chinese and Tibetan works began at once. The script's creation is attributed to Yeli Renrong and work on it likely began during the reign of Deming.


title: Western Xia

text: In 1038, Yuanhao declared himself emperor ("wu zu" or Blue Son of Heaven), posthumously Emperor Jingzong of Western Xia, of the Great Xia with his capital at Xingqing in modern Yinchuan. Jingzong expanded the bureaucratic apparatus mirroring Chinese institutional practices. A Secretariat (Zhongshu sheng), Bureau of Military Affairs (Shumi yuan), Finance Office (San si), Censorate (Yushi tai), and 16 bureaus (shiliu si) under the supervision of a chancellor (shangshu ling) were created. Jingzong enacted a head shaving decree that ordered all his countrymen to shave the top of their heads so that if within three days, someone had not followed his order, they were allowed to be killed.


title: Western Xia

text: In response, the Song dynasty offered to bestow ranks on the Tanguts, which Jingzong rejected. The Song then cut off border trade and put a bounty on his head. The Xia's chief military leader, Weiming Shanyu, also fled to seek asylum with the Song, however he was executed at Youzhou. What ensued was a prolonged war with the Song dynasty which resulted in several victories at great cost to the Xia economy.


title: Western Xia

text: In the winter of 1039–1040, Jingzong laid siege to Yanzhou (now Yan'an) with over 100,000 troops. The prefect of Yanzhou, Fan Yong, gave contradictory orders to his military deputy, Liu Ping, making him move his forces (9,000) in random directions until they were defeated by Xia forces (50,000) at Sanchuan Pass. Liu Ping was taken captive. Despite the defenders' mediocre performance, Jingzong was forced to lift the siege and retreat to a ring of forts overlooking Yanzhou, when heavy winter snows set in. A Song army of 30,000 returned later that winter under the command of Ren Fu. They were ambushed at Haoshuichuan and annihilated. Despite such victories, Jingzong failed to make any headway against Song fortifications, garrisoned by 200,000 troops on rotation from the capital, and remained unable to seize any territory. In 1042, Jingzong advanced south and surrounded the fort of Dingchuan. The defending commander Ge Huaimin lost his nerve and decided to run, abandoning his troops to be slaughtered. Again, Jingzong failed to gain significant territory. Half his soldiers had died from attrition and after two years, Xia could no longer support his military endeavors. Tangut forces began suffering small defeats, being turned back by Song forces at Weizhou and Linzhou.


title: Western Xia

text: The Liao dynasty took advantage of the Song's dire predicaments by increasing annual tribute payments by 100,000 units of silk and silver (each). The Song appealed to the Liao for help, and as a result, Emperor Xingzong of Liao invaded Western Xia with a force of 100,000 in 1044. Liao forces enjoyed an initial victory but failed to take the Xia capital and were brutally mauled by Jingzong's defenders. According to Song spies, there was a succession of carts bearing Liao dead across the desert. Having exhausted his resources, Jingzong made peace with the Song, who recognized him as the ruler of Xia lands and agreed to pay an annual tribute of 250,000 units of silk, silver, and tea.


title: Western Xia

text: Toward the end of the war, Jingzong took the intended bride of his son, Lady Moyi, as his concubine. Jingzong's designated heir, Ninglingge, was the son of the Yeli empress, whose uncle Yeli Wangrong was concerned about the development. Ninglingge was thus arranged to marry the daughter of Wangrong, who planned to kill the emperor on the eve of the wedding. The plot leaked and Wangrong as well as four other Yeli conspirators were executed. The Yeli empress was demoted and Lady Moyi was installed in her place. Another concubine, Lady Mocang, bore the emperor a male child in 1047, named Liangzuo, who was raised by Mocang Epang. The disinherited heir apparent stabbed Jingzong in the nose and fled to Mocang Epang's residence where he was arrested and executed. Jingzong died the next day on 19 January 1048 at the age of 44.


title: Western Xia

text: After Emperor Jingzong of Western Xia died in 1048, a council of elders selected his cousin as the new ruler. Mocang Epang objected on grounds of primogeniture and put forth his nephew, the son of Jingzong and Lady Mocang, as candidate. No dissent was forthcoming, so the two-year-old Liangzuo became emperor, posthumously known as Emperor Yizong of Western Xia. In 1056 the empress dowager died. In 1061 Yizong eliminated Mocang Epang and married Lady Liang, formerly the wife of Epang's son. Yizong appointed Lady Liang's brother, Liang Yimai, as palace minister. This would start two generations of Liang dominance in Xia. During Yizong's reign, he attempted to enact more Chinese forms of governance by replacing Tangut rites with Chinese court ritual and dress, which was opposed by the Liang faction that favored Tangut forms. At the same time, Song and Xia emissaries regularly exchanged insults. The emperor supported sinification through the import of Chinese books, revived the use of his Chinese surname Li and other Chinese protocols, and pursued accommodation with the Song dynasty in border disputes and opening of trade. However, these diplomatic overtures were squandered by arrogant Song representatives who insulted the Xia envoy. The Liang clan was reportedly of Han Chinese ancestry, albeit assimilated into Tangut culture, but their faction would later lead the opposition to the pro-Chinese policy. The Han Chinese empresses of the Liang clan, Paul Forage notes, were more aggressive in their stance against the Song dynasty than the emperors they were representing.


title: Western Xia

text: In 1064, Yizong raided the Song dynasty. In the fall of 1066, he mounted two more raids and in September, an attack on Qingzhou was launched. The Tangut forces destroyed several fortified settlements. Song forces were surrounded for three days before cavalry reinforcements arrived. Yizong was wounded by a crossbow and forced to retreat. Tangut forces attempted another raid later on but failed, and a night attack by Song forces scattered the Tangut army. Yizong regrouped at Qingtang and launched another attack on Qingzhou in December but withdrew after threats by Emperor Yingzong of Song to escalate the conflict. The next year, the Song commander Chong E attacked and captured Suizhou.


title: Western Xia

text: The seven-year-old Bingchang, posthumously Emperor Huizong of Western Xia, succeeded his father, Emperor Yizong of Western Xia. Huizong's reign began with an inconclusive war with the Song dynasty in 1070-1 over Suizhou. In 1072 Huizong's sister was married to Linbuzhi (Rinpoche), the son of the Tsongkha ruler, Dongzhan. These events occurred under the regency of the Empress Dowager Liang and her brother, Liang Yimai. Huizong was married to one of Yimai's daughters to ensure the continued control of the Liang over the imperial Weiming clan. In 1080 Huizong rebelled against his mother's dominance by discarding with Tangut ritual in favor of Chinese ceremonies. A year later a plot by Huizong and his concubine, Li Qing, to turn over the Xia's southern territory to the Song was uncovered. Li Qing was executed and Huizong was imprisoned. The emperor's loyalists immediately rallied their forces to oppose Liang rule while Yimai tried to in vain to summon them with the imperial silver paiza.


title: Western Xia

text: Seeing the infighting breaking out in the Xia, the Song decided to go on the offensive. In 1081, the Song dynasty launched a five-pronged attack on the Xia. After initial victories, Song forces failed to take the capital of Xia, Xingqing, and remained on the defensive for the next three years. Xia counterattacks also experienced initial success before failing to take Lanzhou multiple times. In 1085, the war ended with the death of Emperor Shenzong of Song.


title: Western Xia

text: In the summer of 1081, the five Song armies invaded Western Xia. Chong E defeated a Xia army, killing 8,000. In October, Li Xian took Lanzhou. On 15 October, Liu Changzuo's 50,000 strong army met a Xia force of 30,000 led by the Empress Regent Liang's brother. Liu's commanders advised him to take a defensive position, but he refused, and led a contingent of shield warriors with two ranks of crossbowmen and cavalry behind, with himself leading at the front with two shields. The battle lasted for several hours before the Xia forces retreated, suffering 2,700 casualties. Afterwards, Liu captured a large supply of millet at the town of Mingsha, and headed towards Lingzhou. Liu's vanguard attacked the town's gate before the defenders had a chance to close it, dealing several hundred casualties, and seizing more than 1,000 cattle before retreating. Liu wanted Gao Zunyu to help him take Lingzhou, but Gao refused. Then Liu suggested they take the Xia capital instead, to which Gao also refused, and instead took it as a slight that he could not take Lingzhou. Gao relayed his version of events to the Song court, then had Liu removed from command, merging the two forces.


title: Western Xia

text: By November, the Xia had abandoned the middle of the Ordos plateau, losing Xiazhou. On 20 November, Wang Zhongzheng took Youzhou and slaughtered its inhabitants. At this point Wang became concerned that he would run out of supplies and quarreled with Chong E over provisions. He also forbade his troops from cooking their meals because he feared it would alert Xia raiders of their position. His troops became ill from their uncooked food, started to starve, and came under attack by enemy cavalry anyway. Wang was ordered to withdraw while Chong E covered his retreat. Wang lost 20,000 men.


title: Western Xia

text: On 8 December, Gao Zunyu decided to attack Lingzhou, only to realize he had forgotten to bring any siege equipment, and there were not enough trees around for their construction. Gao took out his frustration on Liu Changzuo, who he tried to have executed. Liu's troops were on the verge of mutiny before Fan Chuncui, a Circuit judge, convinced Gao to reconcile with Liu. On 21 December, Xia forces breached the dikes along the Yellow River and flooded the camps of the two besieging Song armies, forcing them to retreat. Xia harassment turned the retreat into a rout.


title: Western Xia

text: By the end of 1081, only Chong E remained in active command. In September 1082, the Xia counterattacked with a 300,000 strong army, laying siege to Yongle, a fortress town west of Mizhi. The Xia sent out cavalry to prevent Song relief attempts. The defending commander, Xu Xi, deployed his troops outside the town gates but refused to attack the enemy troops while they forded the river. Then he refused to let his troops in when the Tangut Iron Hawk cavalry attacked, decimating the defending army. With the capture of Yongle, the Song lost 17,300 troops.


title: Western Xia

text: In March 1083, Xia forces attacked Lanzhou. The defending commander, Wang Wenyu, led a small contingent out at night and made a surprise attack on the Xia encampment, forcing them to retreat. The Tanguts made two more attempts to take Lanzhou in April and May but failed on both accounts. Their simultaneous attack on Linzhou also failed. After multiple defeats, the Xia offered peace demands to the Song, which they refused. In January 1084, Xia forces made a last attempt to take Lanzhou. The siege lasted for 10 days before the Tangut army ran out of supplies and was forced to retreat.


title: Western Xia

text: The war ended in 1085 with the death of Emperor Shenzong in April. In exchange for 100 Chinese prisoners, the Song returned four of the six captured towns. Hostilities between the Song and Xia would flare up again five years later, and conflict would continue sporadically until the Song lost Kaifeng in the Jingkang incident of 1127.


title: Western Xia

text: Huizong was returned to his throne in 1083. Liang Yimai died in 1085 and his son, Liang Qipu, succeeded his position as chief minister. The Empress Dowager Liang also died later that year. In 1086 Huizong passed away at the age of 26.


title: Western Xia

text: The three-year-old Qianshun succeeded his father, Emperor Huizong of Western Xia, as emperor, posthumously Emperor Chongzong of Western Xia. His mother, the new Empress Dowager Liang, the younger sister of Liang Qipu, ruled as regent. The Song dynasty continued to campaign against the Xia in 1091 and 1093. In 1094, Rende Baozhuang and Weiming Awu slew Liang Qipu and exterminated his clan. In 1096 the Song stopped paying tribute to the Xia and the next year, launched an "advance and fortify" campaign centered on guarding key locations along river valleys and mountains to erode the Xia position. From 1097 to 1099, the Song army constructed 40 fortifications across the Ordos plateau. In 1098, the Empress Regent Liang sent a 100,000 strong army to recapture Pingxia. The Tangut army was completely defeated in their attempt to dislodge the Song from their high ground position, and their generals Weiming Amai and Meiledubu were both captured. Empress Dowager Liang died in 1099, apparently poisoned by assassins from the Liao dynasty. At the same time, the Tanguts were also involved in a war with the Zubu to their north.


title: Western Xia

text: In 1103, the Song annexed Tsongkha and spent the following year weeding out native resistance. The expansion of Song territory threatened the Xia's southern border, resulting in Tangut incursions in 1104 and 1105. Eventually the Xia launched an all out attack on Lanzhou and Qingtang. However, after the Advance and Fortify campaign of 1097–1099, Xia forces were no longer able to defeat Song positions. Failing to take major cities, the Tangut forces went on a rampage, killing tens of thousands of local civilians. The next year, Chongzong made peace with the Song, but was unable to clearly demarcate their borders, leading to another war in 1113.


title: Western Xia

text: In 1113, the Xia started building fortifications in disputed territory with the Song, and took the Qingtang region. Incensed at this provocation, Emperor Huizong of Song dispatched Tong Guan to evict the Tanguts. In 1115, 150,000 troops under the command of Liu Fa penetrated deep into Xia territory and slaughtered the Tangut garrison at Gugulong. Meanwhile, Wang Hou and Liu Chongwu attacked the newly built Tangut fortress of Zangdihe. The siege ended in failure and the death of half the invasion force. Wang bribed Tong to keep the number of casualties a secret from the emperor. The next year, Liu Fa and Liu Chongwu took a walled Tangut city called Rendequan. Another 100,000 troops were sent against Zangdihe and succeeded in taking the fortress. The Xia made a successful counterattack in the winter of 1116–1117. Despite piling casualties on the Song side, Tong was adamant about eradicating the Xia once and for all. He gave orders for Liu Fa to lead 200,000 into the heart of the Xia empire, aiming straight at the capital region. It quickly became apparent that this was a suicide mission. The Song army was met outside the city by an even larger Tangut army led by the Xia prince, Chage. The Tangut army surrounded the Song forces, killing half of them, with the remaining falling back during the night. The Tanguts pursued the Song and defeated them again the next day. Liu was beheaded. A ceasefire was called in 1119 and Huizong issued an apology to Xia.


title: Western Xia

text: In 1122, the Jürchen Jin dynasty took the Southern Capital of the Liao dynasty, and the remaining Khitans fled in two groups to the west. One group led by Xiao Gan fled to Xia where they set up a short lived Xi dynasty that lasted only five months before Gan died at the hands of his own troops. The other group, led by Yelü Dashi, joined Emperor Tianzuo of Liao at the Xia border. In the early summer of 1123, Dashi was captured by the Jin and forced to lead them to Tianzuo's camp, where the entire imperial family except for Tianzuo and one son were captured. Tianzuo sought refuge with Chongzong, who while initially receptive, changed his mind after warnings from the Jurchens and declared himself a vassal of Jin in 1124.


title: Western Xia

text: Domestically the reign of Chongzong saw a formal consolidation of the relationship between the imperial court and the great clans, whose positions were assured in legal documents. After his mother's death in 1099, Chongzong stripped the Rende clan of its military power. Rende Baozhuang was demoted. Chongzong's brother, Chage, was given command of the Tangut army, which he led to many victories against the Song. A state school was established with 300 students supported by government stipends. A "civilian" faction arose under the leadership of the imperial Prince Weiming Renzhong, who often denounced Chage for corruption and abuse of power. Chongzong shuffled appointments to play the two factions against each other. In 1105, Chongzong married a Liao princess, who along with her son, apparently died of heartbreak in 1125 when the Khitan emperor was captured by the Jurchens. In 1138, the penultimate year of his reign, Chongzong took the daughter of Ren Dejing as his empress.


title: Western Xia

text: The 16-year-old Renxiao succeeded his father, Emperor Chongzong of Western Xia, as emperor, posthumously Emperor Renzong of Western Xia. His mother was the Chinese concubine, Lady Cao.


title: Western Xia

text: In 1140 a group of Khitan exiles led by Xiao Heda rebelled. The Xia forces under Ren Dejing crushed them. Renzong wanted to reward Ren with a palace appointment but his councilor, Weiming Renzhong, convinced him to keep him as a field commander.


title: Western Xia

text: In 1142-3 famine and earthquake caused unrest in Xiazhou. Renzong responded with tax remissions and relief measures.


title: Western Xia

text: In 1144 Renzong decreed the establishment of schools throughout the country and a secondary school opened for imperial scions aged seven to fifteen. A Superior School of Chinese Learning was opened the following year and Confucian temples were built throughout the land. In 1147 imperial examinations were instituted, although Tangut records do discuss using them for selection of officials. The Tangut law code only discusses inheritance of office and rank. In 1148 an Inner Academy was established and staffed with renowned scholars. Renzong also greatly patronized Buddhist learning. The majority of the Tangut Tripitaka was completed during his reign. In 1189, the 50th anniversary of Renzong's accession, 100,000 copies of the "Sutra on the visualization of the Maitreya Bodhisattva's ascent and rebirth in Tushita Heaven" (Guan Mile pusa shang sheng Toushuai tian jing) was printed and distributed in both Chinese and Tangut, and 50,000 copies of other sutras were also printed.


title: Western Xia

text: After the deaths of Renzhong and Chage in 1156, Ren Dejing rose through the ranks and became very powerful. In 1160 he obtained the noble title of Chu, the first Chinese to do so in the Tangut state. Ren tried to have the schools shut down and called them useless Chinese institutions wasting resources on parasitic scholars. It is unknown how the emperor responded but the schools were not closed. In 1161 the emperor opened a Hanlin Academy to compile the Xia historical records.


title: Western Xia

text: In 1161-2 the Tanguts briefly occupied territory of both the Jurchen Jin dynasty and Song dynasty during the Jin–Song Wars.


title: Western Xia

text: From 1165 to 1170, Ren Dejing tried to establish his own semi-autonomous realm, and in the process meddled in the affairs of the Zhuanglang tribes, who lived in the border region of the Tao River valley. He also tried to enlist the help of the Jurchens, but they refused his overtures. Ren started construction of fortifications along the Jin border. In 1170 Ren pressured Renzong to grant him the eastern half of the realm as well as for Emperor Shizong of Jin to grant him investiture. In the summer of that year, Renzong's men secretly rounded up Ren Dejing and his adherents, executing them.


title: Western Xia

text: Wo Daochong succeeded Ren Dejing as chief minister. A Confucian scholar, he translated the "Analects" and provided commentary to it in the Tangut language. Upon his death, Renzong honored him by having his portrait displayed in all the Confucian temples and schools.


title: Western Xia

text: The Jurchens closed down border markets in Lanzhou and Baoan in 1172 and would not reopen them until 1197. They accused the Tanguts of trading worthless gems and jades for their silk. Tangut border raids increased during this period until the Jurchens reopened one market in 1181. In 1191 some Tangut herdsmen strayed into Jurchen territory and was chased away by a Jin patrol. They them ambushed and killed the pursuing patrol officer. Renzong refused to extradite the herdsmen and assured the Jurchens that they would be punished.


title: Western Xia

text: The 17-year-old Chunyou succeeded his father, Emperor Renzong of Western Xia, as emperor, posthumously Emperor Huanzong of Western Xia. Little besides the rise of Temüjin and his conflict with Western Xia is known about Huanzong's reign. In 1203, Toghrul was defeated by Temüjin. Toghrul's son, Nilqa Senggum, fled through Tangut territory and although the Tanguts refused to provide him with refuge, and he raided their territory, Temüjin used this as pretext to raid Western Xia. The resulting attack in 1205 caused one local Tangut noble to defect to the Mongols, the plundering of several fortified settlements, and loss of livestock.


title: Western Xia

text: In 1206, Temüjin was formally proclaimed Genghis Khan, ruler of all Mongols, marking the official start of the Mongol Empire. In the same year, Huanzong was deposed in a coup by his cousin Anquan, who installed himself as Emperor Xiangzong of Western Xia. Huanzong died much later in captivity.


title: Western Xia

text: In 1207, Genghis led another raid into Western Xia, invading the Ordos Loop and sacking Wulahai, the main garrison along the Yellow River, before withdrawing in the spring of 1208. The Tanguts tried to form a united front with the Jurchen Jin dynasty against the Mongols, but the usurper monarch, Wanyan Yongji, refused to cooperate and declared that it was to their advantage that enemies attack one another.


title: Western Xia

text: In the autumn of 1209, Genghis received the submission of the Uyghurs to the west and invaded Western Xia. After defeating an army led by Gao Lianghui outside Wulahai, Genghis captured the city and pushed up along the Yellow River, capturing several garrisons and defeating another imperial army. The Mongols besieged the capital, Zhongxing, which held a well-fortified garrison of 150,000, and attempted to flood the city by diverting the Yellow River. The dike they built broke and flooded the Mongol camp, forcing them to withdraw. In 1210, Xiangzong agreed to submit to Mongol rule, and demonstrated his loyalty by giving a daughter, Chaka, in marriage to Genghis and paying a tribute of camels, falcons, and textiles.


title: Western Xia

text: After their defeat in 1210, Western Xia attacked the Jin dynasty in response to their refusal to aid them against the Mongols. The following year, the Mongols joined Western Xia and began a 23-year-long campaign against Jin. In the same year Xiangzong's nephew Zunxu seized power in a coup and became Emperor Shenzong of Western Xia. Xiangzong died a month later.


title: Western Xia

text: Emperor Shenzong of Western Xia was the first person in the imperial family to pass the palace examinations and receive a jinshi degree.


title: Western Xia

text: Shenzong appeased the Mongols by attacking the Jurchens and in 1214, supported a rebellion against the Jurchens. In 1216, Western Xia provided auxiliary troops to the Mongols for an attack on Jin territory. The Tanguts also invited the Song dynasty to join them in attacking the Jin, but nothing came of this except an aborted joint action in 1220. The antagonistic policy towards the Jurchen Jin was unpopular at court, as was cooperating with the Mongols. A certain Asha Gambu emerged as an outspoken proponent of anti-Mongol policy. In the winter of 1217-18, the Mongols called on Western Xia to provide them troops for campaigns further west, but they refused to comply. No immediate retaliation occurred since Genghis left for the west in 1219 and left Muqali in charge of North China. In 1223, Muqali died. At the same time, Shenzong abdicated to his son, Dewang, posthumously Emperor Xianzong of Western Xia.


title: Western Xia

text: Emperor Xianzong of Western Xia began peace talks with the Jurchen Jin in 1224 and the peace agreement was finalized in the fall of 1225. The Tanguts continued to defy the Mongols by refusing to send a hostage prince to the Mongol court.


title: Western Xia

text: After defeating Khwarazm in 1221, Genghis prepared his armies to punish Western Xia. In 1225, Genghis attacked with a force of approximately 180,000. According to the "Secret History of the Mongols", Genghis was injured in 1225 during a horse hunt when his horse bolted from under him. Genghis then tried to offer Western Xia the chance to willingly submit, but Asha Gambhu mocked the Mongols and challenged them to battle. Genghis pledged to avenge this insult. Genghis ordered his generals to systematically destroy cities and garrisons as they went.


title: Western Xia

text: Genghis divided his army and sent general Subutai to take care of the westernmost cities, while the main force under Genghis moved east into the heart of the Western Xia and took Suzhou and Ganzhou, which was spared destruction upon its capture due to it being the hometown of Genghis's commander Chagaan. After taking Khara-Khoto in early 1226, the Mongols began a steady advance southward. Asha, commander of the Western Xia troops, could not afford to meet the Mongols as it would involve an exhausting westward march from the capital through 500 kilometers of desert, so the Mongols steadily advanced from city to city.


title: Western Xia

text: In August 1226, Mongol troops approached Liangzhou, the second-largest city in Western Xia, which surrendered without resistance. In autumn 1226, Genghis crossed the Helan Mountains, and in November laid siege to Lingwu, a mere 30 kilometers from the capital. At this point, Xianzong died, leaving his relative, Xian, posthumously Emperor Mozhu of Western Xia, to deal with the Mongol invasion.


title: Western Xia

text: Emperor Mo of Western Xia led a 300,000 strong army against the Mongols and was defeated. The Mongols sacked Lingzhou.


title: Western Xia

text: Genghis reached the Western Xia capital in 1227, laid siege to the city, and launched several offensives against the Jin to prevent them from sending reinforcements to Western Xia, with one force reaching as a far as Kaifeng, the Jin capital. The siege lasted for six months before Genghis offered terms of surrender. During the peace negotiations, Genghis continued his military operations around the Liupan mountains near Guyuan, rejected a peace offer from the Jin, and prepared to invade them near their border with the Song.


title: Western Xia

text: In August 1227, Genghis died of uncertain causes, and, in order not to jeopardize the ongoing campaign, his death was kept a secret. In September 1227, Emperor Mo surrendered to the Mongols and was promptly executed. The Mongols then pillaged the capital, slaughtered the city's population, plundered the imperial tombs to the west, and completed the annihilation of the Western Xia state.


title: Western Xia

text: The destruction of Western Xia during the second campaign was nearly total. According to John Man, Western Xia is little known to anyone other than experts in the field due to Genghis Khan's policy calling for their complete eradication. He states that "There is a case to be made that this was the first ever recorded example of attempted genocide. It was certainly very successful "ethnocide"." However, some members of the Western Xia royal clan emigrated to western Sichuan, northern Tibet, and even possibly Northeast India, in some instances becoming local rulers. A small Western Xia state was established in Tibet along the upper reaches of the Yalong River while other Western Xia populations settled in what are now the modern provinces of Henan and Hebei. In China, remnants of the Western Xia persisted into the middle of the Ming dynasty.


title: Western Xia

text: The Western Xia had two elite military units, the Iron Hawks (tie yaozi), a 3,000 strong heavy cavalry unit, and Trekker infantry (bubazi), mountain infantry. The brother of Emperor Chongzong of Western Xia, Chage, mentioned that Trekker infantry had difficulty fighting Mighty-Arm bows, a type of Song dynasty crossbow:


title: Western Xia

text: The kingdom developed a Tangut script to write its own Tangut language, a now extinct Tibeto-Burman language.


title: Western Xia

text: Tibetans, Uyghurs, Han, and Tanguts served as officials in Western Xia. It is unclear how distinct the different ethnic groups were in the Xia state as intermarriage was never prohibited. Tangut, Chinese and Tibetan were all official languages.


title: Western Xia

text: In 1034 Li Yuanhao (Emperor Jingzong) introduced and decreed a new custom for Western Xia subjects to shave their heads, leaving a fringe covering the forehead and temples, ostensibly to distinguish them from neighbouring countries. Clothing was regulated for different classes of official and commoners. Dress seemed to be influenced by Tibetan and Uighur clothing.


title: Western Xia

text: The government-sponsored state religion was a blend of Tibetan Tantric Buddhism and Chinese Mahayana Buddhism with a Sino-Nepalese artistic style. The scholar-official class engaged in the study of Confucian classics, Taoist texts, and Buddhist sermons, while the Emperor portrayed himself as a Buddhist king and patron of Lamas.


title: Western Xia

text: Early in the kingdom's history, Chinese Buddhism was the most widespread form of Buddhism practiced. However, around the mid-twelfth century Tibetan Buddhism gained prominence as rulers invited Tibetan monks to hold the distinctive office of state preceptor. The practice of Tantric Buddhism in Western Xia led to the spread of some sexually related customs. Before they could marry men of their own ethnicity when they reached 30 years old, Uighur women in Shaanxi in the 12th century had children after having relations with multiple ethnic Han men, with her desirability as a wife enhancing if she had been with a large number of men.


title: Western Xia

text: The economy of the empire mainly consisted of agriculture, pastoralism, and trade (especially with Central Asia).


title: Western Xia

text: Each Western Xia emperor established one or more era name in Chinese and Tangut, although not all the Tangut versions of era names are known.


title: Polikarpov I-16

text: The Polikarpov I-16 () is a Soviet single-engine single-seat fighter aircraft of revolutionary design; it was the world's first low-wing cantilever monoplane fighter with retractable landing gear to attain operational status and as such "introduced a new vogue in fighter design". The I-16 was introduced in the mid-1930s and formed the backbone of the Soviet Air Force at the beginning of World War II. The diminutive fighter, nicknamed "Ishak" or "Ishachok" ("donkey" or "burro") by Soviet pilots, figured prominently in the Second Sino-Japanese War, the Battle of Khalkhin Gol, Winter War and the Spanish Civil War – where it was called the ' ("rat") by the Nationalists or ' ("fly") by the Republicans. The Finns called the aircraft as "(flying squirrel)".


title: Polikarpov I-16

text: While working on the Polikarpov I-15 biplane, Nikolai Nikolaevich Polikarpov began designing an advanced monoplane fighter. It featured cutting-edge innovations such as retractable landing gear and a fully enclosed cockpit, and was optimized for speed with a short stubby fuselage, and a Wright R-1820 radial engine in a NACA cowling. The aircraft is small, light and simple to build.


title: Polikarpov I-16

text: Full-scale work on the TsKB-12 prototype began in June 1933, and the aircraft was accepted into production on 22 November 1933, a month before it took to the air. The TsKB-12 was of mixed construction, using a wooden monocoque fuselage and wings employing a KhMA chrome-molybdenum steel alloy wing spar, dural ribs and D1 aluminum alloy skinning on the center and leading edges, with the remaining portions of the wings fabric covered. Another modern feature were the ailerons which ran along almost the entire trailing edge of the wing and also operated as flaps (in the manner of more modern flaperons) by drooping 15°. The cockpit was covered by a 40-centimetre-wide (16 in) canopy which featured an Aldis-type tubular gun sight which could slide back and forth on runners fitted with rubber bungee cords. A 225 L (59.4 US gal) fuel tank was fitted directly in front of the cockpit. The main landing gear is fully retractable by a hand crank. The armament consisted of a pair of 7.62×54mmR (0.30 in) ShKAS machine guns in the wings, mounted on the outboard side of the main gear and 900 rounds of ammunition.


title: Polikarpov I-16

text: These features were proposed at first by Andrei Tupolev; however, the NII VVS was more concerned about the stresses a typical combat aircraft was subjected to in combat, and initially considered the risk too great. However, TsAGI, with the help of the 3rd Design Brigade under the leadership of Pavel Sukhoi and Aleksandr Putylov, eventually convinced NII VVS that what was being proposed was not only feasible, but would enhance the aircraft's performance.


title: Polikarpov I-16

text: The TsKB-12 was designed for the Wright Cyclone SR-1820-F-3 9-cylinder radial engine (rated at 529 kW/710 hp); a license to build this engine under the supervision of the OKB-19 Shvetsov design bureau in the Soviet Union was being negotiated. As the license was not yet approved, Polikarpov was asked to settle for the less powerful M-22 (Soviet-built version of the Gnome-Rhone Jupiter 9ASB, which itself was a licensed version of the Bristol Jupiter VI) with 358 kW (480 hp). This was deemed acceptable because the projected top speed still exceeded 300 km/h (185 mph).


title: Polikarpov I-16

text: The M-22-powered TsKB-12 first took to the air on 30 December 1933 with the famous Soviet test pilot Valery Chkalov at the controls. The second TsKB-12, with a Cyclone engine and three-bladed propeller, flew in January of the following year. Initial government trials in February 1934 revealed very good maneuverability, but the aircraft did not tolerate abrupt control inputs. Thus the TsKB-12 was deemed dangerous to fly and all aerobatics were forbidden. The M-22 version was preferred due to the vibration of the Cyclone-powered aircraft. Pilots commented early on about the difficulty of climbing into the cockpit, a trait that persisted through the I-16's service life. Before continuing test flights the designers had to answer the question of spin behavior. Wind tunnel testing suggested that the TsKB-12, with its short tail, would enter an unrecoverable flat spin, but real-life trials were necessary to confirm this. Since Cyclone engines were rare, it was decided to risk the M-22 prototype for this purpose. On 1 and 2 March 1934, Chkalov performed 75 spins and discovered that the aircraft had very benign stall behavior (dipping a wing and recovering without input from the pilot when airspeed increased) and intentional spins could be easily terminated by placing the controls in the neutral position. The stories of vicious spin behavior of the I-16 perpetuated in modern literature is unfounded (perhaps extrapolated from Gee Bee experience). In fact, the I-16's stablemate, the biplane Polikarpov I-153, exhibited much worse spin characteristics.


title: Polikarpov I-16

text: Service trials of the new fighter, designated I-16, began on 22 March 1934. The M-22 prototype reached 359 km/h (223 mph). The pioneering presence of a complex, triple-strut manually retracted main landing gear design was prone to jamming and required considerable strength from the pilot, who directly operated the rearmost strut's upper end, moved with a manually turned jackscrew running spanwise within the wing structure, to "slide" outwards and inwards on each side to respectively get the main gear retracted and extended, with the main strut (the forward-most of the trio) needing to shorten its length during its retraction to fit the mainwheel into the lower fuselage, performed by the middle-location strut's geometric arrangement and pivot locations. Most of the test flights were performed with the gear extended. On 1 May 1934, the M-22 prototype participated in the flyover of Red Square. Approximately thirty I-16 Type 1 aircraft were delivered, but were not assigned to any VVS fighter squadron. Most pilots who flew the I-16 Type 1 for evaluation purposes did not find the aircraft to have many redeeming characteristics. Regardless of pilot opinion, much attention was focused on the Cyclone-powered aircraft and the M-25 (the license-built Cyclone). On 14 April 1934, the Cyclone prototype was damaged when one of the landing gear legs collapsed while it was taxiing.


title: Polikarpov I-16

text: The third prototype with a Cyclone engine incorporated a series of aerodynamic improvements and was delivered for government trials on 7 September 1934. The top speed of 437 km/h (270 mph) no longer satisfied the Air Force, who now wanted the experimental Nazarov M-58 engine and 470 km/h (290 mph). Subsequently, the M-22-powered version entered production at Factory 21 in Nizhny Novgorod and Factory 39 in Moscow. Because it was the fourth aircraft produced by these factories, it received the designation I-16 Type 4. Aircraft fitted with these new engines required a slightly changed airframe, including armor plating for the pilot and changes to the landing gear doors (particularly, the hinged lower mainwheel door) to allow for complete closure.


title: Polikarpov I-16

text: The M-25 fitted I-16, the I-16 Type 5, featured a new engine cowling which was slightly smaller in diameter and featured nine forward-facing, radially-set shuttered openings to control cooling airflow, a redesigned exhaust with eight individual outlet stubs, and other changes. The M-25 was rated at 474 kW (635 hp) at sea level and 522 kW (700 hp) at 2,300 m (7,546 ft). Due to the poor quality of the canopy glazing, the I-16 Type 5 pilots typically left the canopy open or removed the rear portion completely. By the time the Type 5 arrived, it was the world's lightest production fighter (1,460 kg/3,219 lb), as well as the world's fastest, able to reach speeds of 454 km/h (282 mph) at altitude and 395 km/h (245 mph) at sea level. While the Type 5 could not perform the high-G maneuvers of other fighters, it possessed superior speed and climb rates, and had extremely responsive aileron control, which gave it a very good roll rate, which led to precision maneuvers in loops and split-Ss.


title: Polikarpov I-16

text: Initial service experience revealed that the ShKAS machine guns had a tendency to jam. This was the result of the guns being installed in the wings upside-down to facilitate the fit. The problem was addressed in later modifications. Evaluations from pilots confirmed the experience with prototypes. Controls were light and very sensitive, abrupt maneuvers resulted in spins, and spin behavior was excellent. An aileron roll could be performed in under 1.5 seconds (roll rate over 240 degrees/second). The machine guns were fired via a cable and the required effort, coupled with sensitive controls, made precision aiming difficult. The rear weight bias made the I-16 easy to handle on unprepared airfields because the aircraft was rather unlikely to flip over the nose even if the front wheels dug in.


title: Polikarpov I-16

text: The I-16 was a difficult fighter to fly. The pilots had poor visibility, the canopy tended to become fouled with engine oil, and the moving portion was prone to slamming shut during hard maneuvers, which caused many pilots to fix it in the open position. The front section of the fuselage, with the engine, was too close to the centre of gravity, and the pilot's cockpit too far to the rear. The Polikarpov had insufficient longitudinal stability and it was impossible to fly the aircraft "hands off".


title: Polikarpov I-16

text: At the start of the Spanish Civil War in 1936, Republican forces pleaded for fighter aircraft. After receiving payment in gold, Joseph Stalin dispatched around 475 I-16 Type 5s and Type 6s. The first I-16s appeared in Spanish skies in November 1936. The Polikarpov monoplanes had their baptism of fire on 13 November 1936, when twelve I-16s intercepted a Nationalist bombing raid on Madrid. Soviet pilots claimed four air victories and two German Heinkel He 51 pilots were killed. But the Soviets suffered losses too; the group commander collided with an enemy aircraft and another I-16 pilot crash landed. The Polikarpovs immediately began dominating the enemy Heinkel He 51 and Arado Ar 68 biplanes and remained unchallenged until the introduction of the Messerschmitt Bf 109. The arrival of the newest Bf 109Bs and the overwhelming numerical superiority of Nationalist fighters were the primary cause of the heavy I-15 and I-16 combat losses suffered throughout 1937. A number of aviation publications called the new Soviet fighter a "Boeing" due to the incorrect assumption that it was based on the Boeing P-26's design. The Nationalists nicknamed the stubby fighter "Rata" (Rat), while the Republicans affectionately called it "Mosca" (Fly).


title: Polikarpov I-16

text: Combat experience showed that the I-16 had deficiencies; several aircraft were lost after structural failure of the wings which was quickly remedied by reinforced structures. Heavy machine gun bullets could sometimes penetrate the armored backrest and fuel tanks occasionally caught fire in spite of being protected. The hot Spanish summers required the addition of oil radiators, and dust adversely affected the life of the engines. Although some aircraft accumulated up to 400 hours of flying time, the average life of an I-16 was 87 days, of which one sixth was spent on maintenance. The biggest complaint in service was the light armament of only two 7.62 mm (0.30 in) machine guns. This was urgently addressed with the Type 6 which added a third ShKAS in the bottom of the fuselage. The four-gun Type 10 was nicknamed "Super Mosca" or simply "Super".


title: Polikarpov I-16

text: The total number of I-16s delivered to Spain from 1936 to 1938 amounted to 276. When the war ended on 1 April 1939, 187 "Ratas" had been lost in Spain: 112 lost in combat, one shot down by anti-aircraft fire, eleven destroyed on the ground, one force-landed and 62 lost in accidents.


title: Polikarpov I-16

text: Another 250 I-16 Type 10s were supplied to China. This model added a second set of 7.62 mm (0.30 in) ShKAS machine guns, armor behind the pilot, and had a slightly upgraded 560 kW (750 hp) M-25 engine. In 1939, of the 500 I-16s deployed to the fighting at Nomonhan, approximately 112 were lost during the battles of Khalkhin Gol, of which 88 were destroyed in aerial combat, primarily against the all-metal Nakajima Ki-27 Japanese fighters. During test trials in Russia of a captured Ki-27, the aircraft proved superior to the Soviet I-152 (I-15bis), I-153, and the I-16 in aerial combat, as well as having a faster take-off and lower landing speed, requiring shorter airstrips than the I-16, which needed 270 meters to stop and 380 meters for take-off.


title: Polikarpov I-16

text: Further attempts were made to upgrade the firepower of the aircraft using 20 mm (0.79 in) ShVAK cannons, making the I-16 one of the most heavily armed fighters of the period, able to fire 28 rounds of ammunition in three seconds. Pilots loved the results, but the cannons were in short supply, and only a small number of the I-16 Type 12, 17, 27, and 28 were built. The cannons adversely affected performance, with 360° turn time increasing from fifteen seconds in the Type 5 to eighteen seconds. The Type 24 replaced the skid with a tailwheel and featured the much more powerful 670 kW (900 hp) Shvetsov M-63 engine. The Type 29 replaced two of the ShKAS guns with a single 12.7 mm (.50 in) UBS. Ten Type 17 fighters were supplied to the Chinese Air Force where on 20 May 1940, they effectively shot down a C5M scout-attack plane and three G3M bombers during the Battle of Chonqing.


title: Polikarpov I-16

text: Types 18, 24, 27, 28, and 29 could be fitted to carry RS-82 unguided rockets. The first successful use of air-to-air missiles in air combat was on August 20, 1939. A Ki-27 was hit by an RS-82 rocket launched from a distance of about a kilometer. The shot was fired by Captain N. Zvonarev.


title: Polikarpov I-16

text: A 1939 government study found the I-16 had exhausted its performance potential. The addition of armor, radio, battery, and flaps during the aircraft's evolution exacerbated the rear weight distribution problems to the point where the aircraft required considerable forward pressure on the stick to maintain level flight and at the same time developed a tendency to enter uncontrolled dives. Extension and retraction of the landing flaps caused a dramatic change in the aircraft's attitude. Accurate gunfire was difficult.


title: Polikarpov I-16

text: The pilots nicknamed the aircraft "Ishak" (Russian: "Ишак", "Donkey"/"Hinny") because it was similar to the Russian pronunciation of "I-16" ("ee-shestnadtset"). When Operation Barbarossa erupted on 22 June 1941, 1,635 of 4,226 VVS aircraft were I-16s of all variants, fielded by 57 fighter regiments in frontier areas. The main assault delivered by the Luftwaffe's "Luftflotte" 2 (in support of Wehrmacht Army Group Centre) was directed against the Soviet Western Special Military District, that deployed 361 (424 according to other sources) I-16s. During the early phase of the campaign the I-16 bases were the main targets for the German aircraft and after 48 hours of combat, of the 1,635 Polikarpov monoplanes in service on 21 June 1941, only 937 were left. By 30 June the number of I-16s in western front line units had dropped to 873, including 99 that required repairs. To stem the Luftwaffe aerial assault several I-16 pilots adopted the "taran" tactic and sacrificed their lives, ramming German aircraft.