title: Japanese sword

text: Kanemitsu and Nagayoshi of the "Osafune" school were apprentices to Masamune of the Sōshū school, the greatest swordsmith in Japan. While they forged high-quality swords by order, at the same time, from the Muromachi period, when wars became large-scale, they mass-produced low-quality swords for drafted farmers and for export.


title: Japanese sword

text: The Bizen school had enjoyed the highest prosperity for a long time, but declined rapidly due to a great flood which occurred in the late 16th century during the Sengoku period. Their swords are often characterized as curved from the base, with irregular fingerprint-like patterns on the surface of the blade, while the "hamon" has a flashy pattern like a series of cloves, and there is little grain but a color gradient at the boundary of the "hamon". It is often evaluated as a sword with a showy and gorgeous impression.


title: Japanese sword

text: The Sōshū school is a school that originated in Sagami Province, corresponding to present-day Kanagawa Prefecture. Sagami Province was the political center of Japan where the Kamakura shogunate was established in the Kamakura period. At the end of the 13th century, the Kamakura shogunate invited swordsmiths from Yamashiro school and Bizen school, and swordsmiths began to gather. Shintōgo Kunimitsu forged experimental swords by combining the forging technology of Yamashiro school and Bizen school. Masamune, who learned from Shintōgo Kunimitsu, became the greatest swordsmith in Japan. From the lessons of the Mongol invasion of Japan, they revolutionized the forging process to make stronger swords. Although this forging method is not fully understood to date, one of the elements is heating at higher temperatures and rapid cooling. Their revolution influenced other schools to make the highest quality swords, but this technique was lost before the Azuchi–Momoyama period ("Shintō" period). The Sōshū school declined after the fall of the Kamakura shogunate. Their swords are often characterized by a shallow curve, a wide blade to the back, and a thin cross-section. There are irregular fingerprint-like patterns on the surface of the blade, the "hamon" has a pattern of undulations with continuous roundness, and the grains at the boundary of the "hamon" are large.


title: Japanese sword

text: The Mino school is a school that originated in Mino Province, corresponding to present-day Gifu Prefecture. Mino Province was a strategic traffic point connecting the Kanto and Kansai regions, and was surrounded by powerful "daimyo" (feudal lords). The Mino school started in the middle of the Kamakura period, when swordsmiths of the Yamato school who learned from the Sōshū school gathered in Mino. The Mino school became the largest production area of Japanese swords after the Bizen school declined due to a great flood. The production rate of "katana" was high, because it was the newest school among 5 big schools. Their swords are often characterized by a slightly higher central ridge and a thinner back. There are irregular fingerprint-like patterns on the surface of the blade, the "hamon" are various, and the grain on the border of the hamon are hardly visible.


title: Japanese sword

text: The word "katana" was used in ancient Japan and is still used today, whereas the old usage of the word "nihontō" is found in the poem the Song of "Nihontō", by the Song dynasty poet Ouyang Xiu. The word "nihontō" became more common in Japan in the late Tokugawa shogunate. Due to importation of Western swords, the word "nihontō" was adopted in order to distinguish it from the .


title: Japanese sword

text: "Meibutsu" (noted swords) is a special designation given to sword masterpieces which are listed in a compilation from the 18th century called the "Kyoho Meibutsucho". The swords listed are "Koto" blades from several different provinces; 100 of the 166 swords listed are known to exist today, with "Sōshū" blades being very well represented. The "Kyoho Meibutsucho" also listed the nicknames, prices, history and length of the "Meibutsu", with swords by Yoshimitsu, Masamune, Yoshihiro, and Sadamune being very highly priced.


title: Japanese sword

text: Each blade has a unique profile, mostly dependent on the swordsmith and the construction method. The most prominent part is the middle ridge, or "shinogi". In the earlier picture, the examples were flat to the shinogi, then tapering to the blade edge. However, swords could narrow down to the shinogi, then narrow further to the blade edge, or even expand outward towards the shinogi then shrink to the blade edge (producing a trapezoidal shape). A flat or narrowing shinogi is called "shinogi-hikushi", whereas a flat blade is called a "shinogi-takushi".


title: Japanese sword

text: The shinogi can be placed near the back of the blade for a longer, sharper, more fragile tip or a more moderate shinogi near the center of the blade.


title: Japanese sword

text: The sword also has an exact tip shape, which is considered an extremely important characteristic: the tip can be long ("ōkissaki"), medium ("chūkissaki"), short ("kokissaki"), or even hooked backwards ("ikuri-ōkissaki"). In addition, whether the front edge of the tip is more curved ("fukura-tsuku") or (relatively) straight ("fukura-kareru") is also important.


title: Japanese sword

text: The "" (point) is not usually a "chisel-like" point, and the Western knife interpretation of a "tantō point" is rarely found on true Japanese swords; a straight, linearly sloped point has the advantage of being easy to grind, but less stabbing/piercing capabilities compared to traditional Japanese kissaki Fukura (curvature of the cutting edge of tip) types. Kissaki usually have a curved profile, and smooth three-dimensional curvature across their surface towards the edge—though they are bounded by a straight line called the "yokote" and have crisp definition at all their edges. While the straight tip on the "American tanto" is identical to traditional Japanese fukura, two characteristics set it apart from Japanese sword makes: The absolute lack of curve only possible with modern tools, and the use of the word "tanto" in the nomenclature of the western tribute is merely a nod to the Japanese word for knife or short sword, rather than a tip style.


title: Japanese sword

text: Although it is not commonly known, the "chisel point" kissaki originated in Japan. Examples of such are shown in the book "The Japanese Sword" by Kanzan Sato. Because American bladesmiths use this design extensively it is a common misconception that the design originated in America.


title: Japanese sword

text: A hole is punched through the tang "", called a "". It is used to anchor the blade using a "", a small bamboo pin that is inserted into another cavity in the handle "" and through the mekugi-ana, thus restricting the blade from slipping out. To remove the handle one removes the mekugi. The swordsmith's signature "" is carved on the tang.


title: Japanese sword

text: In Japanese, the scabbard is referred to as a "", and the handguard piece, often intricately designed as an individual work of art—especially in later years of the Edo period—was called the "tsuba". Other aspects of the mountings , such as the "" (decorative grip swells), "" (blade collar and scabbard wedge), "" and "" (handle collar and cap), "" (small utility knife handle), "" (decorative skewer-like implement), "" lacquer, and "" (professional handle wrap, also named ), received similar levels of artistry.


title: Japanese sword

text: The "mei" is the signature inscribed on to the tang of the Japanese sword. Fake signatures ("gimei") are common not only due to centuries of forgeries but potentially misleading ones that acknowledge prominent smiths and guilds, and those commissioned to a separate signer.


title: Japanese sword

text: Sword scholars collect and study "oshigata", or paper tang-rubbings, taken from a blade: to identify the mei, the hilt is removed and the sword is held point side up. The mei is chiseled onto the tang on the side which traditionally faces away from the wearer's body while being worn; since the katana and wakizashi are always worn with the cutting edge up, the edge should be held to the viewer's left. The inscription will be viewed as kanji on the surface of the tang: the first two kanji represent the province; the next pair is the smith; and the last, when present, is sometimes a variation of 'made by', or, 'respectfully'. The date will be inscribed near the mei, either with the reign name; the Zodiacal Method; or those calculated from the reign of the legendary Emperor Jimmu, dependent upon the period.


title: Japanese sword

text: What generally differentiates the different swords is their length. Japanese swords are measured in units of "shaku". Since 1891, the modern Japanese shaku is approximately equal to a foot (11.93 inches), calibrated with the meter to equal exactly 10 meters per 33 shaku (30.30 cm).


title: Japanese sword

text: However, the historical shaku was slightly longer (13.96 inches or 35.45 cm). Thus, there may sometimes be confusion about the blade lengths, depending on which shaku value is being assumed when converting to metric or U.S. customary measurements.


title: Japanese sword

text: A blade shorter than one "shaku" is considered a "tantō" (knife). A blade longer than one "shaku" but less than two is considered a "shōtō" (short sword). The wakizashi and "kodachi" are in this category. The length is measured in a straight line across the back of the blade from tip to "munemachi" (where blade meets tang). Most blades that fall into the ""shōtō"" size range are "wakizashi". However, some "daitō" were designed with blades slightly shorter than 2 "shaku". These were called "kodachi" and are somewhere in between a true "daitō" and a "wakizashi". A "shōtō" and a "daitō" together are called a "daishō" (literally, "big-little"). The "daishō" was the symbolic armament of the Edo period samurai.


title: Japanese sword

text: A blade longer than two "shaku" is considered a "daitō", or long sword. To qualify as a "daitō" the sword must have a blade longer than 2 "shaku" (approximately 24 inches or 60 centimeters) in a straight line. While there is a well defined lower limit to the length of a "daitō", the upper limit is not well enforced; a number of modern historians, swordsmiths, etc. say that swords that are over 3 "shaku" in blade length are "longer than normal "daitō"" and are usually referred to as "ōdachi". The word ""daitō"" is often used when explaining the related terms "shōtō" (short sword) and "daishō" (the set of both large and small sword). Miyamoto Musashi refers to the long sword in "The Book of Five Rings". He is referring to the "katana" in this, and refers to the "nodachi" and the "odachi" as "extra-long swords".


title: Japanese sword

text: Before about 1500 most swords were usually worn suspended from cords on a belt, edge-down. This style is called "jindachi-zukuri", and "daitō" worn in this fashion are called "tachi" (average blade length of 75–80 cm). From 1600 to 1867, more swords were worn through an "obi" (sash), paired with a smaller blade; both worn edge-up. This style is called "buke-zukuri", and all "daitō" worn in this fashion are "katana", averaging 70–74 cm (2 shaku 3 sun to 2 shaku 4 sun 5 bu) in blade length. However, Japanese swords of longer lengths also existed, including lengths up to 78 cm (2 shaku 5 sun 5 bu).


title: Japanese sword

text: It was not simply that the swords were worn by cords on a belt, as a 'style' of sorts. Such a statement trivializes an important function of such a manner of bearing the sword. It was a very direct example of 'form following function.' At this point in Japanese history, much of the warfare was fought on horseback. Being so, if the sword or blade were in a more vertical position, it would be cumbersome, and awkward to draw. Suspending the sword by 'cords' allowed the sheath to be more horizontal, and far less likely to bind while drawing it in that position.


title: Japanese sword

text: Abnormally long blades (longer than 3 "shaku"), usually carried across the back, are called "ōdachi" or "nodachi." The word "ōdachi" is also sometimes used as a synonym for Japanese swords. "Odachi" means "great sword", and "Nodachi" translates to "field sword". These greatswords were used during war, as the longer sword gave a foot soldier a reach advantage. These swords are now illegal in Japan. Citizens are not allowed to possess an "odachi" unless it is for ceremonial purposes.


title: Japanese sword

text: Blades whose length is next to a different classification type are described with a prefix 'O-' (for great) or 'Ko-' (for small), e.g. a Wakizashi with a length of 59 cm is called an O-wakizashi (almost a Katana) whereas a Katana of 61 cm is called a Ko-Katana (for small Katana; but note that a small accessory blade sometimes found in the sheath of a long sword is also a "kogatana" (小刀)).


title: Japanese sword

text: Since 1867, restrictions and/or the deconstruction of the samurai class meant that most blades have been worn "jindachi-zukuri" style, like Western navy officers. Since 1953, there has been a resurgence in the "buke-zukuri" style, permitted only for demonstration purposes.


title: Japanese sword

text: The production of swords in Japan is divided into specific time periods: "jōkotō" (ancient swords, until around 900 A.D.), "kotō" (old swords from around 900–1596), "shintō" (new swords 1596–1780), "shinshintō" (new new swords 1781–1876), "gendaitō" (modern or contemporary swords 1876–present)


title: Japanese sword

text: Early examples of iron swords were straight "tsurugi", "chokutō" and others with unusual shapes, some of styles and techniques probably derived from Chinese dao, and some directly imported through trade. The swords of this period were a mixture of swords of Japanese original style and those of Chinese style brought to Japan via the Korean Peninsula and East China Sea. The cross-sectional shape of the blades of these early swords was an isosceles triangular "hira-zukuri", and the "kiriha-zukuri" sword, which sharpened only the part close to the cutting edge side of a planar blade, gradually appeared. Swords of this period are classified as "jōkotō" and are often referred to in distinction from Japanese swords.


title: Japanese sword

text: The direct predecessor of the "tachi" (太刀) has been called "Warabitetō" () by the Emishi (Not to be confused with Ainu) of Tohoku. The Nihonto Meikan shows the earliest and by far the largest group of Ōshū smiths from the beginning of the 8th century were from the Mokusa school, listing over 100 Mokusa smiths before the beginning of the Kamakura period. Archaeological excavations of the Ōshū Tohoku region show iron ore smelting sites dating back to the early Nara period. The Tohoku region and indeed the whole Ōshū district in the 8th century was controlled and populated by the Emishi. Archaeological evidence of recovered "Warabitetō" (蕨手刀) show a high concentration in the burial goods of the Ōshū and Hokkaido regions. Mokusa Area was famous for legendary swordsmiths in the Heian Period (AD 794-1185). They are considered as the original producers of the Japanese swords known as ""Warabitetō" " which can date back to the sixth to eighth centuries. ""Warabitetō" " gained its fame through the series of battles between Emishi people (蝦夷) and the Yamato-chotei government (大 和朝廷) in the late eighth century. Using ""Warabitetō"," the small number of Emishi soldiers could resist against the numerous Yamato-chotei army over a Thirty-Eight Years' War (三十八年戦争) (AD 770-811). The Meikan describes that from earlier time there was a list of forty two famous swordsmiths in the Toukou Meikan 刀工銘鑑 at Kanchiin 観智院. Eight of the swordsmiths on this list were from Ōshū schools. Five from Mokusa being Onimaru 鬼丸, Yoyasu 世安, Morifusa 森房, Hatafusa 幡房 and Gaan 瓦安, two from the Tamatsukuri Fuju 諷誦,Houji 寶次 and one from Gassan signing just Gassan 月山. According to the Nihonto Meikan, the Ōshū swordsmith group consists of the Mokusa (舞草), the Gassan (月山) and the Tamatsukuri (玉造), later to become the Hoju (寶壽) schools. Ōshū swords appear in various old books of this time, for example Heiji Monogatari 平治物語 (Tale of Heiji), Konjaku Monogatari 今昔物語 (Anthology of tales from the past), Kojidan 古事談 (Japanese collection of Setsuwa 説話), and Gikeiki 義経記 (War tale that focuses on the legends of Minamoto no Yoshitsune 源義経 and his followers). Ōshū swordsmiths appeared in books in quite early times compared to others. Tales in these books tell of the Emishi-to in the capital city and these swords seem to have been quite popular with the Bushi. Maybe a badge of honour being captured weapons. For example In “Nihongiryaku” 日本紀略 983AD :” the number of people wearing a funny looking Tachi 太刀 is increasing.” In “Kauyagokau” 高野御幸 1124AD :“ when emperor Shirakawa 白河法皇 visited Kouyasan 高 野山, Fujiwara Zaemon Michisue 藤原左衛門通季 was wearing a Fushū sword “ In “Heihanki” 兵範記 1158AD there was a line that mentioned the Emperor himself had Fushū Tachi.” It seems that during the late Heian the Emishi-to was gaining popularity in Kyoto.


title: Japanese sword

text: In the middle of the Heian period (794–1185), samurai improved on the Warabitetō to develop "Kenukigata-tachi ()" -early Japanese sword-. To be more precise, it is thought that the "Emishi" improved the "warabitetō" and developed "Kenukigata-warabitetō ()" with a hole in the hilt and "kenukigatatō ()" without decorations on the tip of the hilt, and the samurai developed "kenukigata-tachi" based on these swords. "Kenukigata-tachi", which was developed in the first half of the 10th century, has a three-dimensional cross-sectional shape of an elongated pentagonal or hexagonal blade called "shinogi-zukuri" and a gently curved single-edged blade, which are typical features of Japanese swords. There is no wooden hilt attached to "kenukigata-tachi", and the tang ("nakago") which is integrated with the blade is directly gripped and used. The term "kenukigata" is derived from the fact that the central part of tang is hollowed out in the shape of an ancient Japanese tweezers ("kenuki").


title: Japanese sword

text: In the "tachi" developed after "kenukigata-tachi", a structure in which the hilt is fixed to the tang ("nakago") with a pin called "mekugi" was adopted. As a result, a sword with three basic external elements of Japanese swords, the cross-sectional shape of "shinogi-zukuri", a gently curved single-edged blade, and the structure of "nakago", was completed. Its shape may reflects the changing form of warfare in Japan. Cavalry were now the predominant fighting unit and the older straight "chokutō" were particularly unsuitable for fighting from horseback. The curved sword is a far more efficient weapon when wielded by a warrior on horseback where the curve of the blade adds considerably to the downward force of a cutting action. Early models had uneven curves with the deepest part of the curve at the hilt. As eras changed the center of the curve tended to move up the blade.


title: Japanese sword

text: The "tachi" is a sword which is generally larger than a "katana", and is worn suspended with the cutting edge down. This was the standard form of carrying the sword for centuries, and would eventually be displaced by the "katana" style where the blade was worn thrust through the belt, edge up. The "tachi" was worn slung across the left hip. The signature on the tang of the blade was inscribed in such a way that it would always be on the outside of the sword when worn. This characteristic is important in recognizing the development, function, and different styles of wearing swords from this time onwards.


title: Japanese sword

text: When worn with full armour, the "tachi" would be accompanied by a shorter blade in the form known as "koshigatana" (腰刀, "waist sword"); a type of short sword with no handguard, and where the hilt and scabbard meet to form the style of mounting called an "aikuchi" ("meeting mouth"). Daggers ("tantō"), were also carried for close combat fighting as well as carried generally for personal protection.


title: Japanese sword

text: By the 11th century during the Heian period, Japanese swords had already been exported to neighboring countries in Asia. For example, in the poem "The Song of Japanese Swords" Ouyang Xiu, a statesman of the Song Dynasty in China, described Japanese swords as "It is a treasured sword with a scabbard made of fragrant wood covered with fish skin, decorated with brass and copper, and capable of exorcising evil spirits. It is imported at a great cost.".


title: Japanese sword

text: From the Heian period (794－1185), ordinary samurai wore swords of the style called "kurourusi tachi (kokushitsu no tachi, 黒漆太刀)", which meant black lacquer "tachi". The hilt of a "tachi" is wrapped in leather or ray skin, and it is wrapped with black thread or leather cord, and the scabbard is coated with black lacquer. On the other hand, court nobles wore "tachi" decorated with precisely carved metal and jewels for ceremonial purposes. High-ranking court nobles wore swords of the style called "kazari tachi" or "kaza tachi" (飾太刀, 飾剣), which meant decorative "tachi", and lower-ranking court nobles wore simplified "kazatachi" swords of the style called "hosodachi" (細太刀), which meant thin "tachi". The "kazatachi" and "hosodachi" worn by nobles were initially straight like a "chokutō", but since the Kamakura period they have had a gentle curve under the influence of "tachi". Since "tachi" worn by court nobles were for ceremonial use, they generally had an iron plate instead of a blade.


title: Japanese sword

text: In the Kamakura period (1185－1333), high-ranking samurai wore "hyogo gusari tachi (hyogo kusari no tachi, 兵庫鎖太刀)", which meant a sword with chains in the arsenal. The scabbard of the "tachi" was covered with a gilt copper plate and hung by chains at the waist. At the end of the Kamakura period, simplified "hyogo gusari tachi" came to be made as an offering to the "kami" of Shinto shrines and fell out of use as weapons. On the other hand, in the Kamakura period, there was a type of "tachi" called "hirumaki tachi" (蛭巻太刀) with a scabbard covered with metal, which was used as a weapon until the Muromachi period. The meaning was a sword wrapped around a leech, and its feature was that a thin metal plate was spirally wrapped around the scabbard, so it was both sturdy and decorative, and chains were not used to hang the scabbard around the waist.


title: Japanese sword

text: The Mongol invasions of Japan in the 13th century during the Kamakura period spurred further evolution of the Japanese sword. The swordsmiths of the Sōshū school represented by Masamune studied "tachi" that were broken or bent in battle, developed new production methods, and created innovative Japanese swords. They forged the blade using a combination of soft and hard steel to optimize the temperature and timing of the heating and cooling of the blade, resulting in a lighter but more robust blade. They also made the curve of the blade gentle, lengthened the tip linearly, widened the width from the cutting edge to the opposite side of the blade, and thinned the cross section to improve the penetration and cutting ability of the blade.


title: Japanese sword

text: Historically in Japan, the ideal blade of a Japanese sword has been considered to be the (lit., "old swords") in the Kamakura period, and the swordsmiths from the Edo period (1603–1868) to the present day after the (lit., "new swords") period focused on reproducing the blade of the Japanese sword made in Kamakura period. There are more than 100 Japanese swords designated as National Treasures in Japan, of which the "Kotō" of the Kamakura period account for 80% and the "tachi" account for 70%.


title: Japanese sword

text: From the end of the Kamakura period to the end of the Muromachi period (1333－1573), "kawatsutsumi tachi" (革包太刀), which means a "tachi" wrapped in leather, was popular. The "kawatsutsumi tachi" was stronger than the "kurourushi tachi" because its hilt was wrapped in leather or ray skin, lacquer was painted on top of it, leather straps and cords were wrapped around it, and the scabbard and sometimes the "tsuba" (hand guard) were also wrapped in leather.


title: Japanese sword

text: In the Nanboku-chō period (1336－1392) which corresponds to the early Muromachi period (1336－1573), huge Japanese swords such as "ōdachi" became popular. The reason for this is thought to be that the conditions for making a practical large-sized sword were established due to the nationwide spread of strong and sharp swords of the Sōshū school. In the case of "ōdachi" whose blade was 150 cm long, it was impossible to draw a sword from the scabbard on the waist, so people carried it on their back or had their servants carry it. Large "naginata" and "kanabō" were also popular in this period.


title: Japanese sword

text: "Katana" originates from "sasuga", a kind of "tantō" used by lower-ranking samurai who fought on foot in the Kamakura period. Their main weapon was a long "naginata" and "sasuga" was a spare weapon. In the Nanboku-chō period, long weapons such as "ōdachi" were popular, and along with this, "sasuga" lengthened and finally became "katana". Also, there is a theory that "koshigatana" (腰刀), a kind of "tantō" which was equipped by high ranking samurai together with "tachi", developed to "katana" through the same historical background as "sasuga", and it is possible that both developed to "katana". The oldest "katana" in existence today is called "Hishizukuri uchigatana", which was forged in the Nanbokuchō period, and was dedicated to Kasuga Shrine later.


title: Japanese sword

text: By the 15th century, Japanese swords had already gained international fame by being exported to China and Korea. For example, Korea learned how to make Japanese swords by sending swordsmiths to Japan and inviting Japanese swordsmiths to Korea. According to the record of June 1, 1430 in the "Veritable Records of the Joseon Dynasty", a Korean swordsmith who went to Japan and mastered the method of making Japanese swords presented a Japanese sword to the King of Korea and was rewarded for the excellent work which was no different from the swords made by the Japanese.


title: Japanese sword

text: Traditionally, "yumi" (bows) were the main weapon of war in Japan, and "tachi" and "naginata" were used only for close combat. The Ōnin War in the late 15th century in the Muromachi period expanded into a large-scale domestic war, in which employed farmers called "ashigaru" were mobilized in large numbers. They fought on foot using "katana" shorter than "tachi". In the Sengoku period (1467－1615, period of warring states) in the late Muromachi period, the war became bigger and "ashigaru" fought in a close formation using "yari" (spears) lent to them. Furthermore, in the late 16th century, "tanegashima" (muskets) were introduced from Portugal, and Japanese swordsmiths mass-produced improved products, with "ashigaru" fighting with leased guns. On the battlefield in Japan, guns and spears became main weapons in addition to bows. Due to the changes in fighting styles in these wars, the "tachi" and "naginata" became obsolete among samurai, and the "katana", which was easy to carry, became the mainstream. The dazzling looking "tachi" gradually became a symbol of the authority of high-ranking samurai.


title: Japanese sword

text: On the other hand, "kenjutsu" (swordsmanship) that makes use of the characteristics of "katana" was invented. The quicker draw of the sword was well suited to combat where victory depended heavily on short response times. (The practice and martial art for drawing the sword quickly and responding to a sudden attack was called ‘Battōjutsu’, which is still kept alive through the teaching of Iaido.) The "katana" further facilitated this by being worn thrust through a belt-like sash ("obi") with the sharpened edge facing up. Ideally, samurai could draw the sword and strike the enemy in a single motion. Previously, the curved "tachi" had been worn with the edge of the blade facing down and suspended from a belt.


title: Japanese sword

text: From the 15th century, low-quality swords were mass-produced under the influence of the large-scale war. These swords, along with spears, were lent to recruited farmers called "ashigaru" and swords ware exported . Such mass-produced swords are called "kazuuchimono", and swordsmiths of the Bisen school and Mino school produced them by division of labor. The export of Japanese sword reached its height during the Muromachi period when at least 200,000 swords were shipped to Ming Dynasty China in official trade in an attempt to soak up the production of Japanese weapons and make it harder for pirates in the area to arm. In the Ming Dynasty of China, Japanese swords and their tactics were studied to repel pirates, and "wodao" and "miaodao" were developed based on Japanese swords.


title: Japanese sword

text: From this period, the tang () of many old were cut and shortened into . This kind of remake is called (磨上げ). For example, many of the "tachi" that Masamune forged during the Kamakura period were converted into "katana", so his only existing works are "katana" and "tantō". During this period, a great flood occurred in Bizen, which was the largest production area of Japanese swords, and the Bizen school rapidly declined, after which the Mino school flourished.


title: Japanese sword

text: From around the 16th century, many Japanese swords were exported to Thailand, where katana-style swords were made and prized for battle and art work, and some of them are in the collections of the Thai royal family.


title: Japanese sword

text: In the Sengoku period (1467－1615) or the Azuchi–Momoyama period (1568－1600), the "itomaki tachi" ("itomaki no tachi", 糸巻太刀), which means a "tachi" wound with thread, appeared and became the mainstream of "tachi" after that. "itomaki tachi" was decorated with gorgeous lacquer decorations with lots of "maki-e" and flashy colored threads, and was used as a gift, a ceremony, or an offering to the "kami" of Shinto shrines.


title: Japanese sword

text: In later Japanese feudal history, during the Sengoku and Edo periods, certain high-ranking warriors of what became the ruling class would wear their sword "tachi"-style (edge-downward), rather than with the scabbard thrust through the belt with the edge upward. This style of swords is called "handachi", "half "tachi"". In "handachi", both styles were often mixed, for example, fastening to the "obi" was "katana" style, but metalworking of the scabbard was "tachi" style.


title: Japanese sword

text: In the Muromachi period, especially the Sengoku period, anybody such as farmers, townspeople and monks could equip a sword. However, in 1588 during the Azuchi–Momoyama period, Toyotomi Hideyoshi conducted a sword hunt and banned farmers from owning them with weapons.


title: Japanese sword

text: However, Toyotomi's sword hunt couldn't disarm peasants. Farmers and townspeople could wear daisho until 1683. And most of them kept wearing wakizashi on a daily basis until the middle of the 18th century. After then they wore it special times(travel, wedding, funeral) until meiji restoration.


title: Japanese sword

text: Swords forged after 1596 in the Keichō period of the Azuchi-Momoyama period are classified as "shintō" (New swords). Japanese swords since "shintō" are different from "kotō" in forging method and steel ("tamahagane"). This is thought to be because Bizen school, which was the largest swordsmith group of Japanese swords, was destroyed by a great flood in 1590 and the mainstream shifted to Mino school, and because Toyotomi Hideyoshi virtually unified Japan, uniform steel began to be distributed throughout Japan. The "kotō" swords, especially the Bizen school swords made in the Kamakura period, had a "midare-utsuri" like a white mist between "hamon" and "shinogi", but the swords since "shinto" have almost disappeared. In addition, the whole body of the blade became whitish and hard. Almost no one was able to reproduce "midare-utsurii" until Kunihira Kawachi reproduced it in 2014.


title: Japanese sword

text: Japanese swords since the "sintō" period often have gorgeous decorations carved on the blade and lacquered "maki-e" decorations on the scabbard. This was due to the economic development and the increased value of swords as arts and crafts as the Sengoku Period ended and the peaceful Edo Period began. The Umetada school led by Umetada Myoju who was considered to be the founder of "shinto" led the improvement of the artistry of Japanese swords in this period. They were both swordsmiths and metalsmiths, and were famous for carving the blade, making metal accouterments such as "tsuba" (handguard), remodeling from "tachi" to "katana" ("suriage"), and inscriptions inlaid with gold.


title: Japanese sword

text: During this period, the Tokugawa shogunate required samurai to wear "Katana" and shorter swords in pairs. These short swords were "wakizashi" and "tantō", and "wakizashi" were mainly selected. This set of two is called a "daishō". Only "samurai" could wear the "daishō": it represented their social power and personal honour. Samurai could wear decorative sword mountings in their daily lives, but the Tokugawa shogunate regulated the formal sword that samurai wore when visiting a castle by regulating it as a "daisho" made of a black scabbard, a hilt wrapped with white ray skin and black string.


title: Japanese sword

text: Townspeople ("Chōnin") and farmers were allowed to equip a short wakizashi, and the public were often equipped with "wakizashi" on their travels. Under the Tokugawa shogunate, swordmaking and the use of firearms declined. Japanese swords made in this period is classified as "shintō".


title: Japanese sword

text: In the late 18th century, swordsmith Suishinshi Masahide criticized that the present "katana" blades only emphasized decoration and had a problem with their toughness. He insisted that the bold and strong kotō blade from the Kamakura period to the Nanboku-chō period was the ideal Japanese sword, and started a movement to restore the production method and apply it to "katana". "Katana" made after this is classified as a , "new revival swords" or literally "new-new swords." One of the most popular swordsmiths in Japan today is Minamoto Kiyomaro who was active in this "shinshintō" period. His popularity is due to his timeless exceptional skill, as he was nicknamed "Masamune in Yotsuya" and his disastrous life. His works were traded at high prices and exhibitions were held at museums all over Japan from 2013 to 2014.


title: Japanese sword

text: The arrival of Matthew Perry in 1853 and the subsequent Convention of Kanagawa caused chaos in Japanese society. Conflicts began to occur frequently between the forces of "sonnō jōi" (尊王攘夷派), who wanted to overthrow the Tokugawa Shogunate and rule by the Emperor, and the forces of "sabaku" (佐幕派), who wanted the Tokugawa Shogunate to continue. These political activists, called the "shishi" (志士), fought using a practical "katana", called the "kinnōtō" (勤皇刀) or the "bakumatsutō" (幕末刀). Their "katana" were often longer than 90 cm (35.43 in) in blade length, less curved, and had a big and sharp point, which was advantageous for stabbing in indoor battles.


title: Japanese sword

text: In 1867, the Tokugawa Shogunate declared the return of Japan's sovereignty to the Emperor, and from 1868, the government by the Emperor and rapid modernization of Japan began, which was called the Meiji Restoration. The Haitōrei Edict in 1876 all but banned carrying swords and guns on streets. Overnight, the market for swords died, many swordsmiths were left without a trade to pursue, and valuable skills were lost. Swords forged after the Haitōrei Edict are classified as "gendaitō". The craft of making swords was kept alive through the efforts of some individuals, notably Miyamoto kanenori (宮本包則, 1830–1926) and Gassan Sadakazu (月山貞一, 1836–1918), who were appointed Imperial Household Artist. These smiths produced fine works that stand with the best of the older blades for the Emperor and other high-ranking officials. The businessman Mitsumura Toshimo (光村利藻, 1877－1955）tried to preserve their skills by ordering swords and sword mountings from the swordsmiths and craftsmen. He was especially enthusiastic about collecting sword mountings, and he collected about 3,000 precious sword mountings from the end of the Edo period to the Meiji period. About 1200 items from a part of the collection are now in the Nezu Museum.


title: Japanese sword

text: The Japanese sword remained in use in some occupations such as the police force. At the same time, kendo was incorporated into police training so that police officers would have at least the training necessary to properly use one. In time, it was rediscovered that soldiers needed to be armed with swords, and over the decades at the beginning of the 20th century swordsmiths again found work. These swords, derisively called "guntō," were often oil-tempered, or simply stamped out of steel and given a serial number rather than a chiseled signature. The mass-produced ones often look like Western cavalry sabers rather than Japanese swords, with blades slightly shorter than blades of the "shintō" and "shinshintō" periods. In 1934 the Japanese government issued a military specification for the "shin guntō" (new army sword), the first version of which was the Type 94 "Katana", and many machine- and hand-crafted swords used in World War II conformed to this and later "shin guntō" specifications.


title: Japanese sword

text: Under the United States occupation at the end of World War II all armed forces in occupied Japan were disbanded and production of Japanese swords with edges was banned except under police or government permit. The ban was overturned through a personal appeal by Dr. Junji Honma. During a meeting with General Douglas MacArthur, Honma produced blades from the various periods of Japanese history and MacArthur was able to identify very quickly what blades held artistic merit and which could be considered purely weapons. As a result of this meeting, the ban was amended so that "guntō" weapons would be destroyed while swords of artistic merit could be owned and preserved. Even so, many Japanese swords were sold to American soldiers at a bargain price; in 1958 there were more Japanese swords in America than in Japan. The vast majority of these one million or more swords were "guntō", but there were still a sizable number of older swords.


title: Japanese sword

text: After the Edo period, swordsmiths turned increasingly to the production of civilian goods. The Occupation and its regulations almost put an end to the production of Japanese swords. A few smiths continued their trade, and Honma went on to be a founder of the , who made it their mission to preserve the old techniques and blades. Thanks to the efforts of other like-minded individuals, the Japanese swords did not disappear, many swordsmiths continued the work begun by Masahide, and the old swordmaking techniques were rediscovered.


title: Japanese sword

text: Nowadays, "iaitō" is used for "iaidō". Due to their popularity in modern media, display-only Japanese swords have become widespread in the sword marketplace. Ranging from small letter openers to scale replica "wallhangers", these items are commonly made from stainless steel (which makes them either brittle (if made from cutlery-grade 400-series stainless steel) or poor at holding an edge (if made from 300-series stainless steel)) and have either a blunt or very crude edge. There are accounts of good quality stainless steel Japanese swords, however, these are rare at best. Some replica Japanese swords have been used in modern-day armed robberies. As a part of marketing, modern ahistoric blade styles and material properties are often stated as traditional and genuine, promulgating disinformation. Some companies and independent smiths outside Japan produce "katana" as well, with varying levels of quality. According to the Parliamentary Association for the Preservation and Promotion of Japanese Swords, organized by Japanese Diet members, many Japanese swords distributed around the world as of the 21st century are fake Japanese-style swords made in China. The "Sankei Shimbun" analyzed that this is because the Japanese government allowed swordsmiths to make only 24 Japanese swords per person per year in order to maintain the quality of Japanese swords.


title: Japanese sword

text: In Japan, genuine edged hand-made Japanese swords, whether antique or modern, are classified as art objects (and not weapons) and must have accompanying certification in order to be legally owned.


title: Japanese sword

text: Prior to WWII Japan had 1.5million swords in the country – 200,000 of which had been manufactured in factories during the Meiji Restoration. As of 2008, only 100,000 swords remain in Japan. It is estimated that 250,000–350,000 sword have been brought to other nations as souvenirs, art pieces or for Museum purposes. 70% of "daito" (long swords), formerly owned by Japanese officers, have been exported or brought to the United States.


title: Japanese sword

text: Many swordsmiths since the Edo period have tried to reproduce the sword of the Kamakura period which is considered as the best sword in the history of Japanese swords, but they have failed. Then, in 2014, Kunihira Kawachi succeeded in reproducing it and won the Masamune Prize, the highest honor as a swordsmith. No one could win the Masamune Prize unless he made an extraordinary achievement, and in the section of "tachi" and "katana", no one had won for 18 years before Kawauchi.


title: Japanese sword

text: The events of Japanese society have shaped the craft of sword making, as has the sword itself influenced the course of cultural and social development within the nation.


title: Japanese sword

text: The Museum of Fine Arts states that when an artisan plunged the newly crafted sword into the cold water, a portion of his spirit was transferred into the sword. His spirit, morals and state of mind at the time became crucial to the defining of the swords moral and physical characteristics


title: Japanese sword

text: During the Jōmon Period (10,000-1000BCE) swords resembled iron knife blades and were used for hunting, fishing and farming. There is the idea that swords were more than a tool during the Jōmon period, no swords have been recovered to back this hypothesis.


title: Japanese sword

text: The Yayoi Period (1000BCE-300CE) saw the establishment of villages and the cultivation of rice farming within Japan. Rice farming came as a result of Chinese and Korean influence, they were the first group of people to introduce swords into the Japanese Isles. Subsequently, bronze swords were used for religious ceremonies. The Yayoi period saw swords be used primarily for religious and ceremonial purposes.


title: Japanese sword

text: During the Kofun Period (250-538CE) Animism was introduced into Japanese society. Animism is the belief that everything in life contains or is connected to a divine spirits. This connection to the spirit world premediates the introduction of Buddhism into Japan. During this time, China was craving steel blades on the Korean Peninsula. Japan saw this as a threat to national security and felt the need to develop their military technology. As a result, clan leaders took power as military elites, fighting one another for power and territory. As dominant figures took power, loyalty and servitude became an important part of Japanese life – this became the catalyst for the honour culture that is often affiliated with Japanese people.


title: Japanese sword

text: In the Edo period (1603–1868), swords gained prominence in everyday life as the “most important” part of a warrior's amour. The Edo era saw swords became a mechanism for bonding between Daimyo and Samurai. Daimyo would gift samurai's with swords as a token of their appreciation for their services. In turn, samurai would gift Daimyo swords as a sign of respect, most Daimyo would keep these swords as family heirlooms. In this period, it was believed that swords were multifunctional; in spirit they represent proof of military accomplishment, in practice they are coveted weapons of war and diplomatic gifts.


title: Japanese sword

text: The peace of the Edo period saw the demand for swords fall. To retaliate, in 1719 the eighth Tokugawa shogun, Yoshimune, compiled a list of “most famous swords”. Masamune, Awatacuchi Yoshimitsu, and Go no Yoshihiro were dubbed the “Three Famous Smiths”, their swords became sought after by the Daimyo. The prestige and demand for these status symbols spiked the price for these fine pieces.


title: Japanese sword

text: During the Late-Edo period, Suishinshi Masahide wrote that swords should be less extravagant. Swords began to be simplified and altered to be durable, sturdy and made to cut well. In 1543 guns arrived in Japan, changing military dynamic and practicality of swords and samurai's. This period also saw introduction of martial arts as a means to connecting to the spirit world and allowed common people to participate in samurai culture.


title: Japanese sword

text: The Meiji Period (1868–1912) saw the dissolution of the samurai class, after foreign powers demanded Japan open their borders to international trade – 300-hundred years of Japanese isolation came to an end. In 1869 and 1873, two petition were submitted to government to abolish the custom of sword wearing because people feared the outside world would view swords as a “tool for bloodshed” and would consequentially associate Japanese people as violent. Haitōrei (1876) outlawed and prohibited wearing swords in public, with the exception for those in the military and government official; swords lost their meaning within society. Emperor Meiji was determined to westernize Japan with the influence of American technological and scientific advances; however, he himself appreciated the art of sword making. The Meiji era marked the final moments of samurai culture, as samurai's were no match for conscript soldiers who were trained to use western firearms. Some samurai found it difficult to assimilate to the new culture as they were forced to give up their privileges, while others preferred this less-hierarchical way of life. Even with the ban, the Sino-Japanese War (1894) saw Japanese troops wear swords into battle, not for practical use but for symbolic reasons.


title: Japanese sword

text: The Meiji era also saw the integration of Buddhism into Shinto Japanese beliefs. Swords were no longer necessary, in war or lifestyle, and those who practiced martial arts became the “modern samurai” – young children were still groomed to serve the emperor and put loyalty and honour above all else, as this new era of rapid development required loyal, hard working men. The practice of sword making was prohibited, thus swords during the Meiji period were obsolete and a mere symbol of status. Swords were left to rust, sold or melted into more ‘practical’ objects for everyday life.


title: Japanese sword

text: Prior to and during WWII, even with the modernization of the army, the demand for swords exceeded the number of swordsmiths still capable of making them. As a result, swords of this era are of poor quality. In 1933, during the Shōwa era (1926–1989), a sword making factory designed to re-establish the “spirit of Japan” through the art of sword making was built to preserve the legacy and art of swordsmiths and sword making. The government at the time feared that the warrior spirit (loyalty and honour) was disappearing within Japan, along with the integrity and quality of swords.


title: Japanese sword

text: For a portion of the US occupation of Japan, sword making, swordsmiths and wielding of swords was prohibited. As a means to preserve the warrior culture of Japan, martial arts was put into the school curriculum. In 1953, America finally lifted the ban on swords after realizing that sword making is an important cultural asset to preserving Japanese history and legacy.


title: Japanese sword

text: The origins of Japanese swords and their effects and influence on society differs depending on the story that is followed.


title: Japanese sword

text: There is a rich relationship between swords, Japanese culture, and societal development. The different interpretations of the origins of swords and their connection to the spirit world, each hold their own merit within Japanese society, past and present. Which one and how modern-day samurai interpret the history of swords, help influence the kind of samurai and warrior they choose to be.


title: Japanese sword

text: Japanese swords are generally made by a division of labor between six and eight craftsmen. "Tosho" ("Toko", "Katanakaji") is in charge of forging blades, "togishi" is in charge of polishing blades, "kinkosi" ("chokinshi") is in charge of making metal fittings for sword fittings, "shiroganeshi" is in charge of making "habaki" (brade collar), "sayashi" is in charge of making scabbards, "nurishi" is in charge of applying lacquer to scabbards, "tsukamakishi" is in charge of making hilt, and "tsubashi" is in charge of making "tsuba" (hand guard). "Tosho" use apprentice swordsmiths as assistants. Prior to the Muromachi period, "tosho" and "kacchushi" (armorer) used surplus metal to make "tsuba", but from the Muromachi period onwards, specialized craftsmen began to make "tsuba". Nowadays, "kinkoshi" sometimes serves as "shiroganeshi" and "tsubashi".


title: Japanese sword

text: Typical features of Japanese swords represented by "katana" and "tachi" are a three-dimensional cross-sectional shape of an elongated pentagonal or hexagonal blade called "shinogi-zukuri", a style in which the blade and the tang ("nakago") are integrated and fixed to the hilt ("tsuka") with a pin called "mekugi", and a gentle curve.


title: Japanese sword

text: When a "shinogi-zukuri" sword is viewed from the side, there is a ridge line of the thickest part of the blade called "shinogi" between the cutting edge side and the back side. This "shinogi" contributes to lightening and toughening of the blade and high cutting ability.


title: Japanese sword

text: Japanese swords were often forged with different profiles, different blade thicknesses, and varying amounts of grind. "Wakizashi" and "tantō", for instance, were not simply scaled-down versions of "katana"; they were often forged in a shape called "hira-zukuri", in which the cross-sectional shape of the blade becomes an isosceles triangle.


title: Japanese sword

text: The "daishō" was not always forged together. If a samurai was able to afford a "daishō", it was often composed of whichever two swords could be conveniently acquired, sometimes by different smiths and in different styles. Even when a "daishō" contained a pair of blades by the same smith, they were not always forged as a pair or mounted as one. "Daishō" made as a pair, mounted as a pair, and owned/worn as a pair, are therefore uncommon and considered highly valuable, especially if they still retain their original mountings (as opposed to later mountings, even if the later mounts are made as a pair).


title: Japanese sword

text: The forging of a Japanese blade typically took weeks or even months and was considered a sacred art. As with many complex endeavors, rather than a single craftsman, several artists were involved. There was a smith to forge the rough shape, often a second smith (apprentice) to fold the metal, a specialist polisher (called a "togi") as well as the various artisans that made the "koshirae" (the various fittings used to decorate the finished blade and "saya" (sheath) including the "tsuka" (hilt), "fuchi" (collar), "kashira" (pommel), and "tsuba" (hand guard)). It is said that the sharpening and polishing process takes just as long as the forging of the blade itself.


title: Japanese sword

text: The legitimate Japanese sword is made from Japanese steel "Tamahagane". The most common lamination method the Japanese sword blade is formed from is a combination of two different steels: a harder outer jacket of steel wrapped around a softer inner core of steel. This creates a blade which has a hard, razor sharp cutting edge with the ability to absorb shock in a way which reduces the possibility of the blade breaking when used in combat. The "hadagane", for the outer skin of the blade, is produced by heating a block of raw steel, which is then hammered out into a bar, and the flexible back portion. This is then cooled and broken up into smaller blocks which are checked for further impurities and then reassembled and reforged. During this process the billet of steel is heated and hammered, split and folded back upon itself many times and re-welded to create a complex structure of many thousands of layers. Each different steel is folded differently, in order to provide the necessary strength and flexibility to the different steels. The precise way in which the steel is folded, hammered and re-welded determines the distinctive grain pattern of the blade, the "jihada", (also called "jigane" when referring to the actual surface of the steel blade) a feature which is indicative of the period, place of manufacture and actual maker of the blade. The practice of folding also ensures a somewhat more homogeneous product, with the carbon in the steel being evenly distributed and the steel having no voids that could lead to fractures and failure of the blade in combat.


title: Japanese sword

text: The shingane (for the inner core of the blade) is of a relatively softer steel with a lower carbon content than the hadagane. For this, the block is again hammered, folded and welded in a similar fashion to the hadagane, but with fewer folds. At this point, the hadagane block is once again heated, hammered out and folded into a ‘U’ shape, into which the shingane is inserted to a point just short of the tip. The new composite steel billet is then heated and hammered out ensuring that no air or dirt is trapped between the two layers of steel. The bar increases in length during this process until it approximates the final size and shape of the finished sword blade. A triangular section is cut off from the tip of the bar and shaped to create what will be the kissaki. At this point in the process, the blank for the blade is of rectangular section. This rough shape is referred to as a .


title: Japanese sword

text: The is again heated, section by section and hammered to create a shape which has many of the recognisable characteristics of the finished blade. These are a thick back (), a thinner edge (), a curved tip (), notches on the edge () and back () which separate the blade from the tang (). Details such as the ridge line () another distinctive characteristic of the Japanese sword, are added at this stage of the process. The smith's skill at this point comes into play as the hammering process causes the blade to naturally curve in an erratic way, the thicker back tending to curve towards the thinner edge, and he must skillfully control the shape to give it the required upward curvature. The is finished by a process of filing and scraping which leaves all the physical characteristics and shapes of the blade recognisable. The surface of the blade is left in a relatively rough state, ready for the hardening processes. The is then covered all over with a clay mixture which is applied more thickly along the back and sides of the blade than along the edge. The blade is left to dry while the smith prepares the forge for the final heat treatment of the blade, the yaki-ire, the hardening of the cutting edge.


title: Japanese sword

text: This process takes place in a darkened smithy, traditionally at night, in order that the smith can judge by eye the colour and therefore the temperature of the sword as it is repeatedly passed through the glowing charcoal. When the time is deemed right (traditionally the blade should be the colour of the moon in February and August which are the two months that appear most commonly on dated inscriptions on the tang), the blade is plunged edge down and point forward into a tank of water. The precise time taken to heat the sword, the temperature of the blade and of the water into which it is plunged are all individual to each smith and they have generally been closely guarded secrets. Legend tells of a particular smith who cut off his apprentice's hand for testing the temperature of the water he used for the hardening process. In the different schools of swordmakers there are many subtle variations in the materials used in the various processes and techniques outlined above, specifically in the form of clay applied to the blade prior to the yaki-ire, but all follow the same general procedures.


title: Japanese sword

text: The application of the clay in different thicknesses to the blade allows the steel to cool more quickly along the thinner coated edge when plunged into the tank of water and thereby develop into the harder form of steel called martensite, which can be ground to razor-like sharpness. The thickly coated back cools more slowly retaining the pearlite steel characteristics of relative softness and flexibility. The precise way in which the clay is applied, and partially scraped off at the edge, is a determining factor in the formation of the shape and features of the crystalline structure known as the hamon. This distinctive tempering line found near the edge is one of the main characteristics to be assessed when examining a blade.


title: Japanese sword

text: The martensitic steel which forms from the edge of the blade to the hamon is in effect the transition line between these two different forms of steel, and is where most of the shapes, colours and beauty in the steel of the Japanese sword are to be found. The variations in the form and structure of the hamon are all indicative of the period, smith, school or place of manufacture of the sword. As well as the aesthetic qualities of the hamon, there are, perhaps not unsurprisingly, real practical functions. The hardened edge is where most of any potential damage to the blade will occur in battle. This hardened edge is capable of being reground and sharpened many times, although the process will alter the shape of the blade. Altering the shape will allow more resistance when fighting in hand-to-hand combat.


title: Japanese sword

text: Almost all blades are decorated, although not all blades are decorated on the visible part of the blade. Once the blade is cool, and the mud is scraped off, grooves and markings (hi or bo-hi) may be cut into it. One of the most important markings on the sword is performed here: the file markings. These are cut into the tang or the hilt-section of the blade, where they will be covered by the hilt later. The tang is never supposed to be cleaned; doing this can reduce the value of the sword by half or more. The purpose is to show how well the steel ages.


title: Japanese sword

text: Some other marks on the blade are aesthetic: dedications written in Kanji characters as well as engravings called "horimono" depicting gods, dragons, or other acceptable beings. Some are more practical. The presence of a groove (the most basic type is called a "hi") reduces the weight of the sword yet keeps its structural integrity and strength.


title: Japanese sword

text: The "tachi" became the primary weapon on the battlefield during the Kamakura period, used by cavalry. The sword was mostly considered as a secondary weapon until then, used in the battlefield only after the bow and polearm were no longer feasible. During the Edo period samurai went about on foot unarmored, and with much less combat being fought on horseback in open battlefields the need for an effective close quarter weapon resulted in samurai being armed with daishō.


title: Japanese sword

text: Testing of swords, called "tameshigiri", was practiced on a variety of materials (often the bodies of executed criminals) to test the sword's sharpness and practice cutting technique.


title: Japanese sword

text: "Kenjutsu" is the Japanese martial art of using the Japanese swords in combat. The Japanese swords are primarily a cutting weapon, or more specifically, a slicing one. Its moderate curve, however, allowed for effective thrusting as well. The hilt was held with two hands, though a fair amount of one-handed techniques exist. The placement of the right hand was dictated by both the length of the handle and the length of the wielder's arm. Two other martial arts were developed specifically for training to draw the sword and attack in one motion. They are "battōjutsu" and "iaijutsu", which are superficially similar, but do generally differ in training theory and methods.


title: Japanese sword

text: For cutting, there was a specific technique called ""ten-uchi"." "Ten-uchi" refers to an organized motion made by arms and wrist, during a descending strike. As the sword is swung downwards, the elbow joint drastically extends at the last instant, popping the sword into place. This motion causes the swordsman's grip to twist slightly and if done correctly, is said to feel like wringing a towel (Thomas Hooper reference). This motion itself caused the sword's blade to impact its target with sharp force, and is used to break initial resistance. From there, fluidly continuing along the motion wrought by "ten-uchi", the arms would follow through with the stroke, dragging the sword through its target. Because the Japanese swords slices rather than chops, it is this "dragging" which allows it to do maximum damage, and is thus incorporated into the cutting technique. At full speed, the swing will appear to be full stroke, the sword passing through the targeted object. The segments of the swing are hardly visible, if at all. Assuming that the target is, for example, a human torso, "ten-uchi" will break the initial resistance supplied by shoulder muscles and the clavicle. The follow through would continue the slicing motion, through whatever else it would encounter, until the blade inherently exited the body, due to a combination of the motion and its curved shape.


title: Japanese sword

text: Nearly all styles of "kenjutsu" share the same five basic guard postures. They are as follows; "chūdan-no-kamae" (middle posture), "jōdan-no-kamae" (high posture), "gedan-no-kamae" (low posture), "hassō-no-kamae" (eight-sided posture), and "waki-gamae" (side posture).


title: Japanese sword

text: The Japanese swords razor-edge was so hard that upon hitting an equally hard or harder object, such as another sword's edge, chipping became a definite risk. As such, blocking an oncoming blow blade-to-blade was generally avoided. In fact, evasive body maneuvers were preferred over blade contact by most, but, if such was not possible, the flat or the back of the blade was used for defense in many styles, rather than the precious edge. A popular method for defeating descending slashes was to simply beat the sword aside. In some instances, an "umbrella block", positioning the blade overhead, diagonally (point towards the ground, pommel towards the sky), would create an effective shield against a descending strike. If the angle of the block was drastic enough, the curve of the Japanese swords blade would cause the attacker's blade to slide along its counter and off to the side.


title: Japanese sword

text: Japanese swords were carried in several different ways, varying throughout Japanese history. The style most commonly seen in "samurai" movies is called "buke-zukuri", with the katana (and "wakizashi", if also present) carried edge up, with the sheath thrust through the "obi" (sash).


title: Japanese sword

text: The sword would be carried in a sheath and tucked into the samurai's belt. Originally, they would carry the sword with the blade turned down. This was a more comfortable way for the armored samurai to carry his very long sword or to draw while mounted. The bulk of the samurai armor made it difficult to draw the sword from any other place on his body. When unarmored, samurai would carry their sword with the blade facing up. This made it possible to draw the sword and strike in one quick motion. In one such method of drawing the sword, the samurai would turn the sheath downward ninety degrees and pull it out of his sash just a bit with his left hand, then gripping the hilt with his right hand he would slide it out while sliding the sheath back to its original position.


title: Japanese sword

text: Historically, Japanese swords have been regarded not only as weapons but also as works of art, especially for high-quality ones. For a long time, Japanese people have developed a unique appreciation method in which the blade is regarded as the core of their aesthetic evaluation rather than the sword mountings decorated with luxurious lacquer or metal works.


title: Japanese sword

text: It is said that the following three objects are the most noteworthy objects when appreciating a blade. The first is the overall shape referred to as "sugata". Curvature, length, width, tip, and shape of tang of the sword are the objects for appreciation. The second is a fine pattern on the surface of the blade, which is referred to as "hada" or "jigane". By repeatedly folding and forging the blade, fine patterns such as fingerprints, tree rings and bark are formed on its surface. The third is "hamon". Hamon is a white pattern of the cutting edge produced by quenching and tempering. The object of appreciation is the shape of hammon and the crystal particles formed at the boundary of hammon. Depending on the size of the particles, they can be divided into two types, a "nie" and a "nioi", which makes them look like stars or mist. In addition to these three objects, a swordsmith signature and a file pattern engraved on tang, and a carving inscribed on the blade, which is referred to as "horimono", are also the objects of appreciation.


title: Japanese sword

text: The Hon'ami clan, which was an authority of appraisal of Japanese swords, rated Japanese swords from these artistic points of view. In addition, experts of modern Japanese swords judge when and by which swordsmith school the sword was made from these artistic points of view.


title: Japanese sword

text: Generally, the blade and the sword mounting of Japanese swords are displayed separately in museums, and this tendency is remarkable in Japan. For example, the Nagoya Japanese Sword Museum "Nagoya Touken World", one of Japan's largest sword museums, posts separate videos of the blade and the sword mounting on its official website and YouTube.


title: Japanese sword

text: In Japan, Japanese swords are rated by authorities of each period, and some of the authority of the rating is still valid today.


title: Japanese sword

text: In 1719, Tokugawa Yoshimune, the 8th shogun of the Tokugawa shogunate, ordered Hon'ami Kōchū, who was an authority of sword appraisal, to record swords possessed by "daimyo" all over Japan in books. In the completed ""Kyōhō Meibutsu Chō"" (享保名物帳) 249 precious swords were described, and additional 25 swords were described later. The list also includes 81 swords that had been destroyed in previous fires. The precious swords described in this book were called ""Meibutsu"" (名物) and the criteria for selection were artistic elements, origins and legends. The list of "Meibutsu" includes 59 swords made by Masamune, 34 by Awataguchi Yoshimitsu and 22 by Go Yoshihiro, and these 3 swordsmiths were considered special. "Daimyo" hid some swords for fear that they would be confiscated by the Tokugawa Shogunate, so even some precious swords were not listed in the book. For example, "Daihannya Nagamitsu" and "Yamatorige", which are now designated as National Treasures, were not listed.


title: Japanese sword

text: Yamada Asaemon V, who was the official sword cutting ability examiner and executioner of the Tokugawa shogunate, published a book ""Kaiho Kenjaku"" (懐宝剣尺) in 1797 in which he ranked the cutting ability of swords. The book lists 228 swordsmiths, whose forged swords are called ""Wazamono"" (業物) and the highest ""Saijo Ō Wazamono"" (最上大業物) has 12 selected. In the reprinting in 1805, 1 swordsmith was added to the highest grade, and in the major revised edition in 1830 ""Kokon Kajibiko"" (古今鍛冶備考), 2 swordsmiths were added to the highest grade, and in the end, 15 swordsmiths were ranked as the highest grade. The "katana" forged by Nagasone Kotetsu, one of the top-rated swordsmith, became very popular at the time when the book was published, and many counterfeits were made. In these books, the 3 swordsmiths treated specially in ""Kyōhō Meibutsu Chō"" and Muramasa, who was famous at that time for forging swords with high cutting ability, were not mentioned. The reasons for this are considered to be that Yamada was afraid of challenging the authority of the shogun, that he could not use the precious sword possessed by the daimyo in the examination, and that he was considerate of the legend of Muramasa's curse.


title: Japanese sword

text: At present, by the Law for the Protection of Cultural Properties, important swords of high historical value are designated as Important Cultural Properties ("Jūyō Bunkazai", 重要文化財), and special swords among them are designated as National Treasures ("Kokuhō", 国宝). The swords designated as cultural properties based on the law of 1930, which was already abolished, have the rank next to Important Cultural Properties as Important Art Object ("Jūyō Bijutsuhin", 重要美術品). In addition, The Society for Preservation of Japanese Art Swords, a public interest incorporated foundation, rates high-value swords in four grades, and the highest grade Special Important Sword ("Tokubetsu Juyo Token", 特別重要刀剣) is considered to be equivalent to the value of Important Art Object. Although swords owned by the Japanese Imperial Family are not designated as National Treasures or Important Cultural Properties because they are outside the jurisdiction of the Law for the Protection of Cultural Properties, there are many swords of the National Treasure class, and they are called ""Gyobutsu"" (御物).


title: Japanese sword

text: Currently, there are several authoritative rating systems for swordsmiths. According to the rating approved by the Japanese government, from 1890 to 1947, 2 swordsmiths who were appointed as Imperial Household Artist and after 1955, 6 swordsmiths who were designated as Living National Treasure are regarded as the best swordsmiths. According to the rating approved by The Society for Preservation of Japanese Art Swords, a public interest incorporated foundation, 39 swordsmiths who were designated as "Mukansa" (無鑑査) since 1958 are considered to be the highest ranking swordsmiths. The best sword forged by Japanese swordsmiths is awarded the most honorable Masamune prize by The Society for Preservation of Japanese Art Swords. Since 1961, 8 swordsmiths have received the Masamune Prize, and among them, 3 swordsmiths, Masamine Sumitani, Akitsugu Amata and Toshihira Osumi, have received the prize 3 times each and Sadakazu Gassan II has received the prize 2 times. These 4 persons were designated both Living National Treasures and "Mukansa".


title: Western Hemisphere

text: The Western Hemisphere is the half of the planet Earth that lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere. Politically, the term Western Hemisphere is often used as a metonymy for the Americas, even though geographically the hemisphere also includes parts of other continents.


title: Western Hemisphere

text: The Western Hemisphere consists of the Americas, excluding some of the Aleutian Islands to the southwest of the Alaskan mainland; the westernmost portion of Europe, both mainland and islands; the westernmost portion of Africa, both mainland and islands; the extreme eastern tip of the Russian mainland and islands (North Asia); numerous territories in Oceania; and a large portion of Antarctica.


title: Western Hemisphere

text: The center of the Western Hemisphere is located in the Pacific Ocean at the intersection of the 90th meridian west and the Equator, among the Galápagos Islands. The nearest land is Genovesa Island at .


title: Western Hemisphere

text: The tallest freestanding structure in the Western Hemisphere is the CN Tower in Toronto at and the tallest building in the Western Hemisphere is One World Trade Center in New York City at .


title: Western Hemisphere

text: In an attempt to match the Western Hemisphere more closely with the Americas, some sources use the 20th meridian west and the diametrically opposed 160th meridian east to define the hemisphere. This definition excludes all of the European and African mainlands, but still includes some islands associated with these continents, more of eastern Russia and Oceania, and part of Antarctica. It includes all islands of Alaska, but excludes a small portion of northeast Greenland. There is no hemisphere that includes all of the Americas while excluding all land outside of it, regardless of the meridians or points chosen to define it.


title: Western Hemisphere

text: Below is a list of the sovereign states in both the Western and Eastern hemispheres on the IERS Reference Meridian, in order from north to south:


title: Western Hemisphere

text: Below is a list of additional sovereign states which are in both the Western and Eastern hemispheres along the 180th meridian, in order from north to south. (France is not listed below due to its inclusion above, though the meridian does pass Wallis and Futuna.) With the exception of the United States (due to "Wake Island", "Guam" and the "Northern Mariana Islands"), all of them are located on just one side of the International Date Line, which curves around them.


title: Western Hemisphere

text: The following countries and territories lie outside the Americas yet are entirely, mostly, or partially within the Western Hemisphere:


title: Kidney stone disease

text: Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine stream. A small stone may pass without causing symptoms. If a stone grows to more than , it can cause blockage of the ureter, resulting in sharp and severe pain in the lower back or abdomen. A stone may also result in blood in the urine, vomiting, or painful urination. About half of people who have had a kidney stone will have another within ten years.


title: Kidney stone disease

text: Most stones form by a combination of genetics and environmental factors. Risk factors include high urine calcium levels, obesity, certain foods, some medications, calcium supplements, hyperparathyroidism, gout and not drinking enough fluids. Stones form in the kidney when minerals in urine are at high concentration. The diagnosis is usually based on symptoms, urine testing, and medical imaging. Blood tests may also be useful. Stones are typically classified by their location: nephrolithiasis (in the kidney), ureterolithiasis (in the ureter), cystolithiasis (in the bladder), or by what they are made of (calcium oxalate, uric acid, struvite, cystine).


title: Kidney stone disease

text: In those who have had stones, prevention is by drinking fluids such that more than two liters of urine are produced per day. If this is not effective enough, thiazide diuretic, citrate, or allopurinol may be taken. It is recommended that soft drinks containing phosphoric acid (typically colas) be avoided. When a stone causes no symptoms, no treatment is needed; otherwise, pain control is usually the first measure, using medications such as nonsteroidal anti-inflammatory drugs or opioids. Larger stones may be helped to pass with the medication tamsulosin or may require procedures such as extracorporeal shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy.


title: Kidney stone disease

text: Between 1% and 15% of people globally are affected by kidney stones at some point in their lives. In 2015, 22.1 million cases occurred, resulting in about 16,100 deaths. They have become more common in the Western world since the 1970s. Generally, more men are affected than women. Kidney stones have affected humans throughout history with descriptions of surgery to remove them dating from as early as 600 BC.


title: Kidney stone disease

text: The hallmark of a stone that obstructs the ureter or renal pelvis is excruciating, intermittent pain that radiates from the flank to the groin or to the inner thigh. This is due to the transfer of referred pain signals from the lower thoracic splanchnic nerves to the lumbar splanchnic nerves as the stone passes down from the kidney or proximal ureter to the distal ureter. This pain, known as renal colic, is often described as one of the strongest pain sensations known. Renal colic caused by kidney stones is commonly accompanied by urinary urgency, restlessness, hematuria, sweating, nausea, and vomiting. It typically comes in waves lasting 20 to 60 minutes caused by peristaltic contractions of the ureter as it attempts to expel the stone.


title: Kidney stone disease

text: The embryological link between the urinary tract, the genital system, and the gastrointestinal tract is the basis of the radiation of pain to the gonads, as well as the nausea and vomiting that are also common in urolithiasis. Postrenal azotemia and hydronephrosis can be observed following the obstruction of urine flow through one or both ureters.


title: Kidney stone disease

text: Pain in the lower-left quadrant can sometimes be confused with diverticulitis because the sigmoid colon overlaps the ureter, and the exact location of the pain may be difficult to isolate due to the proximity of these two structures.


title: Kidney stone disease

text: Dehydration from low fluid intake is a major factor in stone formation. Individuals living in warm climates are at higher risk due to increased fluid loss. Obesity, immobility, and sedentary lifestyles are other leading risk factors.


title: Kidney stone disease

text: High dietary intake of animal protein, sodium, sugars including honey, refined sugars, fructose and high fructose corn syrup, and excessive consumption of fruit juices may increase the risk of kidney stone formation due to increased uric acid excretion and elevated urinary oxalate levels (whereas tea, coffee, wine and beer may decrease the risk).


title: Kidney stone disease

text: Kidney stones can result from an underlying metabolic condition, such as distal renal tubular acidosis, Dent's disease, hyperparathyroidism, primary hyperoxaluria, or medullary sponge kidney. 3–20% of people who form kidney stones have medullary sponge kidney.


title: Kidney stone disease

text: Kidney stones are more common in people with Crohn's disease; Crohn's disease is associated with hyperoxaluria and malabsorption of magnesium.


title: Kidney stone disease

text: A person with recurrent kidney stones may be screened for such disorders. This is typically done with a 24-hour urine collection. The urine is analyzed for features that promote stone formation.


title: Kidney stone disease

text: Calcium is one component of the most common type of human kidney stones, calcium oxalate. Some studies suggest that people who take calcium or vitamin D as a dietary supplement have a higher risk of developing kidney stones. In the United States, kidney stone formation was used as an indicator of excess calcium intake by the Reference Daily Intake committee for calcium in adults.


title: Kidney stone disease

text: In the early 1990s, a study conducted for the Women's Health Initiative in the US found that postmenopausal women who consumed 1000 mg of supplemental calcium and 400 international units of vitamin D per day for seven years had a 17% higher risk of developing kidney stones than subjects taking a placebo. The Nurses' Health Study also showed an association between supplemental calcium intake and kidney stone formation.


title: Kidney stone disease

text: Unlike supplemental calcium, high intakes of dietary calcium do not appear to cause kidney stones and may actually protect against their development. This is perhaps related to the role of calcium in binding ingested oxalate in the gastrointestinal tract. As the amount of calcium intake decreases, the amount of oxalate available for absorption into the bloodstream increases; this oxalate is then excreted in greater amounts into the urine by the kidneys. In the urine, oxalate is a very strong promoter of calcium oxalate precipitation—about 15 times stronger than calcium.


title: Kidney stone disease

text: A 2004 study found that diets low in calcium are associated with a higher overall risk for kidney stone formation. For most individuals, other risk factors for kidney stones, such as high intakes of dietary oxalates and low fluid intake, play a greater role than calcium intake.


title: Kidney stone disease

text: Calcium is not the only electrolyte that influences the formation of kidney stones. For example, by increasing urinary calcium excretion, high dietary sodium may increase the risk of stone formation.


title: Kidney stone disease

text: Drinking fluoridated tap water may increase the risk of kidney stone formation by a similar mechanism, though further epidemiologic studies are warranted to determine whether fluoride in drinking water is associated with an increased incidence of kidney stones. High dietary intake of potassium appears to reduce the risk of stone formation because potassium promotes the urinary excretion of citrate, an inhibitor of calcium crystal formation.


title: Kidney stone disease

text: Kidney stones are more likely to develop, and to grow larger, if a person has low dietary magnesium. Magnesium inhibits stone formation.


title: Kidney stone disease

text: Diets in Western nations typically contain a large proportion of animal protein. Eating animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate. Urinary excretion of excess sulfurous amino acids (e.g., cysteine and methionine), uric acid, and other acidic metabolites from animal protein acidifies the urine, which promotes the formation of kidney stones. Low urinary-citrate excretion is also commonly found in those with a high dietary intake of animal protein, whereas vegetarians tend to have higher levels of citrate excretion. Low urinary citrate, too, promotes stone formation.


title: Kidney stone disease

text: The evidence linking vitamin C supplements with an increased rate of kidney stones is inconclusive. The excess dietary intake of vitamin C might increase the risk of calcium-oxalate stone formation. The link between vitamin D intake and kidney stones is also tenuous.


title: Kidney stone disease

text: Excessive vitamin D supplementation may increase the risk of stone formation by increasing the intestinal absorption of calcium; correction of a deficiency does not.


title: Kidney stone disease

text: When the urine becomes supersaturated (when the urine solvent contains more solutes than it can hold in solution) with one or more calculogenic (crystal-forming) substances, a seed crystal may form through the process of nucleation. Heterogeneous nucleation (where there is a solid surface present on which a crystal can grow) proceeds more rapidly than homogeneous nucleation (where a crystal must grow in a liquid medium with no such surface), because it requires less energy. Adhering to cells on the surface of a renal papilla, a seed crystal can grow and aggregate into an organized mass. Depending on the chemical composition of the crystal, the stone-forming process may proceed more rapidly when the urine pH is unusually high or low.


title: Kidney stone disease

text: Supersaturation of the urine with respect to a calculogenic compound is pH-dependent. For example, at a pH of 7.0, the solubility of uric acid in urine is 158 mg/100 mL. Reducing the pH to 5.0 decreases the solubility of uric acid to less than 8 mg/100 mL. The formation of uric-acid stones requires a combination of hyperuricosuria (high urine uric-acid levels) and low urine pH; hyperuricosuria alone is not associated with uric-acid stone formation if the urine pH is alkaline. Supersaturation of the urine is a necessary, but not a sufficient, condition for the development of any urinary calculus. Supersaturation is likely the underlying cause of uric acid and cystine stones, but calcium-based stones (especially calcium oxalate stones) may have a more complex cause.


title: Kidney stone disease

text: While supersaturation of urine may lead to crystalluria, it does not necessarily promote the formation of a kidney stone because the particle may not reach the sufficient size needed for renal attachment. On the other hand, Randall's plaques, which were first identified by Alexander Randall in 1937, are calcium phosphate deposits that form in the papillary interstitium and are thought to be the nidus required for stone development. In addition to Randall's plugs, which form in the Duct of Bellini, these structures can generate reactive oxygen species that further enhance stone formation.


title: Kidney stone disease

text: Some bacteria have roles in promoting stone formation. Specifically, urease-positive bacteria, such as "Proteus mirabilis" can produce the enzyme urease, which converts urea to ammonia and carbon dioxide. This increases the urinary pH and promotes struvite stone formation. Additionally, non-urease producing bacteria can provide bacteria components that can promote calcium oxalate crystallization, though this mechanism is poorly understood.


title: Kidney stone disease

text: Normal urine contains chelating agents, such as citrate, that inhibit the nucleation, growth, and aggregation of calcium-containing crystals. Other endogenous inhibitors include calgranulin (an S-100 calcium-binding protein), Tamm–Horsfall protein, glycosaminoglycans, uropontin (a form of osteopontin), nephrocalcin (an acidic glycoprotein), prothrombin F1 peptide, and bikunin (uronic acid-rich protein). The biochemical mechanisms of action of these substances have not yet been thoroughly elucidated. However, when these substances fall below their normal proportions, stones can form from an aggregation of crystals.


title: Kidney stone disease

text: Sufficient dietary intake of magnesium and citrate inhibits the formation of calcium oxalate and calcium phosphate stones; in addition, magnesium and citrate operate synergistically to inhibit kidney stones. The efficacy of magnesium in subduing stone formation and growth is dose-dependent.


title: Kidney stone disease

text: Hypocitraturia or low urinary-citrate excretion (variably defined as less than 320 mg/day) can be a contributing cause of kidney stones in up to 2/3 of cases. The protective role of citrate is linked to several mechanisms; citrate reduces urinary supersaturation of calcium salts by forming soluble complexes with calcium ions and by inhibiting crystal growth and aggregation. Therapy with potassium citrate is commonly prescribed in clinical practice to increase urinary citrate and to reduce stone formation rates. Alkali citrate is also used to increase urine citrate levels. It can be prescribed or found over-the-counter in pill, liquid or powder form.


title: Kidney stone disease

text: Diagnosis of kidney stones is made on the basis of information obtained from the history, physical examination, urinalysis, and radiographic studies. Clinical diagnosis is usually made on the basis of the location and severity of the pain, which is typically colicky in nature (comes and goes in spasmodic waves). Pain in the back occurs when calculi produce an obstruction in the kidney. Physical examination may reveal fever and tenderness at the costovertebral angle on the affected side.


title: Kidney stone disease

text: Calcium-containing stones are relatively radiodense, and they can often be detected by a traditional radiograph of the abdomen that includes the kidneys, ureters, and bladder (KUB film). KUB radiograph, although useful in monitoring size of stone or passage of stone in stone formers, might not be useful in the acute setting due to low sensitivity. Some 60% of all renal stones are radiopaque. In general, calcium phosphate stones have the greatest density, followed by calcium oxalate and magnesium ammonium phosphate stones. Cystine calculi are only faintly radiodense, while uric acid stones are usually entirely radiolucent.


title: Kidney stone disease

text: In people with a history of stones, those who are less than 50 years of age and are presenting with the symptoms of stones without any concerning signs do not require helical CT scan imaging. A CT scan is also not typically recommended in children.


title: Kidney stone disease

text: Otherwise a noncontrast helical CT scan with sections is the diagnostic method to use to detect kidney stones and confirm the diagnosis of kidney stone disease. Near all stones are detectable on CT scans with the exception of those composed of certain drug residues in the urine, such as from indinavir.


title: Kidney stone disease

text: Where a CT scan is unavailable, an intravenous pyelogram may be performed to help confirm the diagnosis of urolithiasis. This involves intravenous injection of a contrast agent followed by a KUB film. Uroliths present in the kidneys, ureters, or bladder may be better defined by the use of this contrast agent. Stones can also be detected by a retrograde pyelogram, where a similar contrast agent is injected directly into the distal ostium of the ureter (where the ureter terminates as it enters the bladder).


title: Kidney stone disease

text: Renal ultrasonography can sometimes be useful, because it gives details about the presence of hydronephrosis, suggesting that the stone is blocking the outflow of urine. Radiolucent stones, which do not appear on KUB, may show up on ultrasound imaging studies. Other advantages of renal ultrasonography include its low cost and absence of radiation exposure. Ultrasound imaging is useful for detecting stones in situations where X-rays or CT scans are discouraged, such as in children or pregnant women. Despite these advantages, renal ultrasonography in 2009 was not considered a substitute for noncontrast helical CT scan in the initial diagnostic evaluation of urolithiasis. The main reason for this is that, compared with CT, renal ultrasonography more often fails to detect small stones (especially ureteral stones) and other serious disorders that could be causing the symptoms.


title: Kidney stone disease

text: On the contrary, a 2014 study suggested that ultrasonography should be used as the initial diagnostic imaging test, with further imaging studies be performed at the discretion of the physician on the basis of clinical judgment, and using ultrasonography rather than CT as an initial diagnostic test results in less radiation exposure and equally good outcome.


title: Kidney stone disease

text: By far, the most common type of kidney stones worldwide contains calcium. For example, calcium-containing stones represent about 80% of all cases in the United States; these typically contain calcium oxalate either alone or in combination with calcium phosphate in the form of apatite or brushite. Factors that promote the precipitation of oxalate crystals in the urine, such as primary hyperoxaluria, are associated with the development of calcium oxalate stones. The formation of calcium phosphate stones is associated with conditions such as hyperparathyroidism and renal tubular acidosis.


title: Kidney stone disease

text: Oxaluria is increased in patients with certain gastrointestinal disorders including inflammatory bowel disease such as Crohn's disease or in patients who have undergone resection of the small bowel or small-bowel bypass procedures. Oxaluria is also increased in patients who consume increased amounts of oxalate (found in vegetables and nuts). Primary hyperoxaluria is a rare autosomal recessive condition that usually presents in childhood.


title: Kidney stone disease

text: Calcium oxalate crystals can come in two varieties. Calcium oxalate monohydrate can appear as 'dumbbells' or as long ovals that resemble the individual posts in a picket fence. Calcium oxalate dihydrate have a tetragonal “envelope” appearance.


title: Kidney stone disease

text: About 10–15% of urinary calculi are composed of struvite (ammonium magnesium phosphate, NHMgPO·6HO). Struvite stones (also known as "infection stones," urease, or triple-phosphate stones) form most often in the presence of infection by urea-splitting bacteria. Using the enzyme urease, these organisms metabolize urea into ammonia and carbon dioxide. This alkalinizes the urine, resulting in favorable conditions for the formation of struvite stones. "Proteus mirabilis", "Proteus vulgaris", and "Morganella morganii" are the most common organisms isolated; less common organisms include "Ureaplasma urealyticum" and some species of "Providencia", "Klebsiella", "Serratia", and "Enterobacter". These infection stones are commonly observed in people who have factors that predispose them to urinary tract infections, such as those with spinal cord injury and other forms of neurogenic bladder, ileal conduit urinary diversion, vesicoureteral reflux, and obstructive uropathies. They are also commonly seen in people with underlying metabolic disorders, such as idiopathic hypercalciuria, hyperparathyroidism, and gout. Infection stones can grow rapidly, forming large calyceal staghorn (antler-shaped) calculi requiring invasive surgery such as percutaneous nephrolithotomy for definitive treatment.


title: Kidney stone disease

text: Struvite stones (triple-phosphate/magnesium ammonium phosphate) have a 'coffin lid' morphology by microscopy.


title: Kidney stone disease

text: About 5–10% of all stones are formed from uric acid. People with certain metabolic abnormalities, including obesity, may produce uric acid stones. They also may form in association with conditions that cause hyperuricosuria (an excessive amount of uric acid in the urine) with or without hyperuricemia (an excessive amount of uric acid in the serum). They may also form in association with disorders of acid/base metabolism where the urine is excessively acidic (low pH), resulting in precipitation of uric acid crystals. A diagnosis of uric acid urolithiasis is supported by the presence of a radiolucent stone in the face of persistent urine acidity, in conjunction with the finding of uric acid crystals in fresh urine samples.


title: Kidney stone disease

text: As noted above (section on calcium oxalate stones), people with inflammatory bowel disease (Crohn's disease, ulcerative colitis) tend to have hyperoxaluria and form oxalate stones. They also have a tendency to form urate stones. Urate stones are especially common after colon resection.


title: Kidney stone disease

text: Uric acid stones appear as pleomorphic crystals, usually diamond-shaped. They may also look like squares or rods which are polarizable.


title: Kidney stone disease

text: People with certain rare inborn errors of metabolism have a propensity to accumulate crystal-forming substances in their urine. For example, those with cystinuria, cystinosis, and Fanconi syndrome may form stones composed of cystine. Cystine stone formation can be treated with urine alkalinization and dietary protein restriction. People affected by xanthinuria often produce stones composed of xanthine. People affected by adenine phosphoribosyltransferase deficiency may produce 2,8-dihydroxyadenine stones, alkaptonurics produce homogentisic acid stones, and iminoglycinurics produce stones of glycine, proline, and hydroxyproline. Urolithiasis has also been noted to occur in the setting of therapeutic drug use, with crystals of drug forming within the renal tract in some people currently being treated with agents such as indinavir, sulfadiazine, and triamterene.


title: Kidney stone disease

text: Urolithiasis refers to stones originating anywhere in the urinary system, including the kidneys and bladder. Nephrolithiasis refers to the presence of such stones in the kidneys. Calyceal calculi are aggregations in either the minor or major calyx, parts of the kidney that pass urine into the ureter (the tube connecting the kidneys to the urinary bladder). The condition is called ureterolithiasis when a calculus is located in the ureter. Stones may also form or pass into the bladder, a condition referred to as bladder stones.


title: Kidney stone disease

text: Stones less than in diameter pass spontaneously in up to 98% of cases, while those measuring in diameter pass spontaneously in less than 53% of cases.


title: Kidney stone disease

text: Stones that are large enough to fill out the renal calyces are called "staghorn stones" and are composed of struvite in a vast majority of cases, which forms only in the presence of urease-forming bacteria. Other forms that can possibly grow to become staghorn stones are those composed of cystine, calcium oxalate monohydrate, and uric acid.


title: Kidney stone disease

text: Preventative measures depend on the type of stones. In those with calcium stones, drinking plenty of fluids, thiazide diuretics and citrate are effective as is allopurinol in those with high uric acid levels in urine.


title: Kidney stone disease

text: Specific therapy should be tailored to the type of stones involved. Diet can have an effect on the development of kidney stones. Preventive strategies include some combination of dietary modifications and medications with the goal of reducing the excretory load of calculogenic compounds on the kidneys. Dietary recommendations to minimize the formation of kidney stones include


title: Kidney stone disease

text: Maintenance of dilute urine by means of vigorous fluid therapy is beneficial in all forms of kidney stones, so increasing urine volume is a key principle for the prevention of kidney stones. Fluid intake should be sufficient to maintain a urine output of at least per day. A high fluid intake may reduce the likelihood of kidney stone recurrence or may increase the time between stone development without unwanted effects.