A Japanese sword (Japanese: 日本刀, Hepburn: nihontō) is one of several types of traditionally made swords from Japan. Bronze swords were made as early as the Yayoi period (1,000 BC – 300 AD), though most people generally refer to the curved blades made from the Heian period (794–1185) to the present day when speaking of "Japanese swords". There are many types of Japanese swords that differ by size, shape, field of application, and method of manufacture. Some of the more commonly known types of Japanese swords are the katana, tachi, ōdachi, wakizashi, and tantō.
== Etymology == 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 to distinguish it from the Western sword (洋刀, yōtō). 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.
Anatomy
Blade
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. 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. 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. The kissaki (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. 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. A hole is punched through the tang nakago, called a mekugi-ana. It is used to anchor the blade using a mekugi, a small bamboo pin that is inserted into another cavity in the handle tsuka and through the mekugi-ana, thus restricting the blade from slipping out. To remove the handle one removes the mekugi. The swordsmith's signature mei is carved on the tang.
Mountings
In Japanese, the scabbard is referred to as a saya, 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 (koshirae), such as the menuki (decorative grip swells), habaki (blade collar and scabbard wedge), fuchi and kashira (handle collar and cap), kozuka (small utility knife handle), kogai (decorative skewer-like implement), saya lacquer, and tsuka-ito (professional handle wrap, also named tsukamaki), received similar levels of artistry.
Signature and date
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.
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.
Length
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). 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. The three main divisions of Japanese blade length are:
Less than 1 shaku for tantō (knife or dagger). Between 1 and 2 shaku for shōtō (小刀:しょうとう) (wakizashi or kodachi). Greater than 2 shaku for daitō (大刀) (long sword, such as katana or tachi). 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. 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". 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). 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. 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. Here is a list of lengths for different types of blades:
Nodachi, Ōdachi, Jin tachi: 90.9 cm and over (more than three shaku) Tachi, Katana: over 60.6 cm (more than two shaku) Wakizashi: between 30.3 and 60.6 cm (between one and two shaku) Tantō, Aikuchi: under 30.3 cm (less than one shaku) 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)). 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.
Classification
Classification by shape and usage
In modern times the most commonly known type of Japanese sword is the Shinogi-Zukuri katana, which is a single-edged and usually curved sabre traditionally worn by samurai from the 15th century onwards. Western historians have said that Japanese katana were among the finest cutting weapons in world military history, for their intended use. Other types of Japanese swords include: tsurugi or ken, which is a straight double-edged sword; ōdachi, tachi, which are older styles of a very long curved single-edged sword; uchigatana, a slightly shorter curved single-edged long sword; wakizashi, a medium-sized sword; and tantō, which is an even smaller knife-sized sword. Naginata, nagamaki, and yari, despite being polearms, are still considered to be swords, which is a common misconception; naginata, nagamaki and yari differ from swords. The type classifications for Japanese swords indicate the combination of a blade and its mounts as this, then, determines the style of use of the blade. An unsigned and shortened blade that was once made and intended for use as a tachi may be alternately mounted in tachi koshirae and katana koshirae. It is properly distinguished, then, by the style of mount it currently inhabits. A long tanto may be classified as a wakizashi due to its length being over 30 cm (12 in); however, it may have originally been mounted and used as a tanto making the length distinction somewhat arbitrary but necessary when referring to unmounted short blades. When the mounts are taken out of the equation, a tanto and wakizashi will be determined by length under or over 30 cm (12 in), unless their intended use can be absolutely determined or the speaker is rendering an opinion on the intended use of the blade. In this way, a blade formally attributed as a wakizashi due to length may be informally discussed between individuals as a tanto because the blade was made during an age where tanto were popular and the wakizashi as a companion sword to katana did not yet exist. The following are types of Japanese swords:
Tsurugi/Ken (剣; "sword"): A straight two-edged sword that was mainly produced prior to the 10th century. After the 10th century, they completely disappeared as weapons and came to be made only as offerings to Shinto shrines and Buddhist temples. Chokutō (直刀; "straight sword"): A straight single edged sword that was mainly produced prior to the 10th century. Since the 10th century, they disappeared as weapons and came to be made only as offerings to Shinto shrines and Buddhist temples. Tachi (太刀; "long sword"): A sword that is generally longer and more curved than the later katana, with curvature often centered from the middle or towards the tang, and often including the tang. Tachi were worn suspended, with the edge downward. The tachi was in vogue before the 15th century. Kodachi (小太刀; "small Tachi"): A shorter version of the tachi, but with similar mounts and intended use, mostly found in the 13th century or earlier. Ōdachi (大太刀; "large Tachi")/Nodachi (野太刀; "field Tachi"): A longer version of the tachi, generally with a blade length of more than 90 cm (35 in), mostly found in the 14th century or later. Uchigatana (打刀; "striking sword"): A sword with a curved blade longer than 60 cm (24 in) (there is no upper length limit but generally they are shorter than 90 cm (35 in)), worn with the edge upwards in the sash. It was developed from sasuga, a kind of tantō, around the 14th century, and became the mainstream replacing tachi from the 15th century onwards. Wakizashi (脇差; "side inserted [sword]"): A general term for a sword between one and two shaku long (30 and 60 cm (12 and 24 in) in modern measurements), predominantly made after 1600. Generally it is the short blade that accompanies a katana in the traditional samurai daisho pairing of swords, but may be worn by classes other than the samurai as a single blade, also worn edge up as the katana. The name derives from the way the sword would be stuck at one's side through the sash. Tantō (短刀; "short blade"): A sword with a blade shorter than one shaku (30 cm (12 in)). Tantō are generally classified as a sword, but its usage is the same as that of a knife. Usually one-edged, but some were double-edged, though asymmetrical. There are other bladed weapons made in the same traditional manner as Japanese swords, which are not swords, but are still classified as Japanese swords (nihontō) (as "tō" means "blade", rather than specifically "sword") because of the way they are made in a similar manner to Japanese swords:
Nagamaki (長巻; "long wrapping"): A sword with an exceptionally long handle, usually about as long as the blade. The name refers to the length of the handle wrapping. Naginata (なぎなた, 薙刀): A polearm with a curved single-edged blade. Naginata mounts consist of a long wooden pole, different from a nagamaki mount, which is shorter and wrapped. Yari (槍; "spear"): A spear, or spear-like polearm. Yari have various blade forms, from a simple double edged and flat blade, to a triangular cross section double edged blade, to those with a symmetric cross-piece (jumonji-yari) or those with an asymmetric cross piece. The main blade is symmetric and straight, unlike a naginata, and usually smaller, but can be as large as or bigger than some naginata blades. Other edged weapons or tools that are made using the same methods as Japanese swords:
Arrowheads for war, yajiri (or yanone). Kogatana (小刀; "small blade"): An accessory or utility knife, sometimes found mounted in a pocket on the side of the scabbard of a sword. A typical blade is about 10 cm (3.9 in) long and 1 cm (0.39 in) wide, and is made using the same techniques as the larger sword blades. Also referred to as a "Kozuka" (小柄), which literally means 'small handle', but this terminology can also refer to the handle and the blade together. In entertainment media, the kogatana is sometimes shown as a throwing weapon, but its real purpose was the same as a 'pocket knife' in the West.
Classification by period
Each Japanese sword is classified according to when the blade was made.:
Jōkotō (上古刀 "ancient swords", until around 900 A.D.) Kotō (古刀 "old swords" from around 900–1596) Shintō (新刀 "new swords" 1596–1780) Shinshintō (新々刀 "new new swords" 1781–1876) Gendaitō (現代刀 "modern or contemporary swords" 1876–present) Historically in Japan, the ideal blade of a Japanese sword has been considered to be the kotō in the Kamakura period, and the swordsmiths from the Edo period to the present day from the Shinto period focused on reproducing the blade of a Japanese sword in the 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%. Japanese swords since shintō are different from kotō in forging method and steel. This was due to the destruction of the Bizen school due to a great flood, the spread of the Mino school, and the virtual unification of Japan by Toyotomi Hideyoshi, which made almost no difference in the steel used by each school. Japanese swords since the Shintō 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. Japanese swords are still commonly seen today; antique and modern forged swords can be found and purchased. Modern, authentic Japanese swords (nihontō) are made by a few hundred swordsmiths. Many examples can be seen at an annual competition hosted by the All Japan Swordsmith Association (AJSA), under the auspices of the Nihontō Bunka Shinkō Kyōkai (Society for the Promotion of Japanese Sword Culture). However, to maintain the quality of Japanese swords, the Japanese government limits the number of Japanese swords a swordsmith can make in a year to 24 (up to 2 swords per month). Therefore, many of the swords called "Japanese sword" distributed around the world today are made in China, and the manufacturing process and quality are not authorized.
=== Classification by school === Many old Japanese swords can be traced back to one of five provinces, each of which had its own school, traditions, and "trademarks" (e.g., the swords from Mino province were "from the start famous for their sharpness"). These schools are known as Gokaden (The Five Traditions). In the Kotō era there were several other schools that did not fit within the Five Traditions or were known to mix elements of each Gokaden, and they were called wakimono (small school). There were 19 commonly referenced wakimono. The number of swordsmiths of Gokaden, as confirmed by signatures and documents, were 4005 in Bizen, 1269 in Mino, 1025 in Yamato, 847 in Yamashiro and 438 in Sōshū. These traditions and provinces are as follows:
Yamato school
The Yamato school is a school that originated in Yamato Province corresponding to present-day Nara Prefecture. Nara was the capital of ancient Japan. Since there is a legend that it was a swordsmith named Amakuni who first signed the tang of a sword, he is sometimes regarded as the founder and the oldest school. However, the founder identified in the material is Yukinobu in the Heian period. They forged the swords that were often worn by monk warriors called sōhei in Nara's large temples. The Yamato school consists of five schools: Senjuin, Shikkake, Taima, Tegai, and Hōshō. Each school forged swords under the supervision of a different temple. In the middle of the Muromachi period, swordsmiths moved to various places such as Mino, and the school disappeared. Their swords are often characterized by a deep curve, a narrow width from blade to back, a high central ridge, and a small tip. There are direct lines on the surface of the blade, the hamon is linear, and the grain at the boundary of the hamon is medium in size. It is often evaluated as a sword with a simple and strong impression.
Yamashiro school
The Yamashiro school is a school that originated in Yamashiro Province, corresponding to present-day Kyoto Prefecture. When Emperor Kanmu relocated the capital to Kyoto in 794, swordsmiths began to gather. The founder of the school was Sanjō Munechika in the late 10th century in the Heian period. The Yamashiro school consisted of schools such as Sanjō, Ayanokōji, Awataguchi, and Rai. At first, they often forged swords in response to aristocrats' demands, so importance was placed on aesthetics and practicality was not emphasized. However, when a domestic conflict occurred at the end of the Heian period, practicality was emphasized and a swordsmith was invited from the Bizen school. In the Kamakura period, tachi from a magnificent rai school became popular among samurai. After that, they also adopted the forging method of Sōshū school. Their swords are often characterized as long and narrow, curved from the base or center, and have a sparkle on the surface of the blade, with the hamon being straight and the grains on the boundary of the hamon being small. It is often evaluated as a sword with an elegant impression.
Bizen school
The Bizen school is a school that originated in Bizen Province, corresponding to present-day Okayama Prefecture. Bizen has been a major production area of high-quality iron sand since ancient times. The Ko-bizen school in the mid Heian period was the originator. The Bizen school consisted of schools such as Ko-bizen, Fukuoka-ichimonji, Osafune, and Hatakeda. According to a sword book written in the Kamakura period, out of the 12 best swordsmiths in Japan who were convened by the Retired Emperor Go-Toba, 10 were from the Bizen school. Great swordsmiths were born one after another in the Osafune school which started in the Kamakura period, and it developed to the largest school in the history of Japanese swords. 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. 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.
Sōshū school
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.
Mino school
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 five 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.
== History == 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)
Jōkotō – Kotō (Old swords)
Early examples of iron swords included straight tsurugi, chokutō, and other unusual shapes. Some of the styles and techniques were derived from Chinese dao, and some were 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 near the cutting edge of a planar blade, gradually appeared. Swords of this period are classified as jōkotō and are often referred to in distinction from Japanese swords.
The direct predecessor of the tachi is the warabitetō (ja:蕨手刀). 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 in the Ōshū Domain of the Tōhoku region have uncovered iron ore smelting sites dating back to the early Nara period. The Tohoku region and indeed the whole Ōshū Domain in the 8th century was controlled and populated by the Emishi. Archaeological evidence of recovered Warabitetō show a high concentration in the burial goods of the Ōshū and Hokkaido regions. The Mokusa area was famous for legendary swordsmiths in the Heian (794–1185). They are considered the original producers of the warabitetō, which date to the sixth to eighth centuries. The warabitetō became famous through the series of battles between the Emishi and the Yamato state in the late eighth century. Using warabitetō, a small number of Emishi soldiers could resist a large Yamato army throughout the Thirty-Eight Years' War (770–811). The Meikan states that, in an earlier time, there was a list of 42 famous swordsmiths in the Tōkō 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), which later became the Hoju (寶壽) schools. Ōshū swords appear in various old books of this time, such as the Heiji Monogatari, Konjaku Monogatari, Kojidan 古事談, 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 quite early, compared to others. Tales in these books tell of 'Emishi swords' in the capital city, which seem to have been quite popular with the samurai. For example, in the Nihongiryaku 日本紀略 of 983: "the number of people wearing a funny-looking tachi is increasing." In the "Kauyagokau" 高野御幸 of 1124: "When Emperor Shirakawa visited Kōyasan, Fujiwara Zaemon Michisue (藤原左衛門通季) was wearing a Fushū sword." The Heihanki (兵範記) of 1158 mentions that the Emperor himself had a Fushū tachi. It seems that during the late Heian, the 'Emishi sword' was gaining popularity in Kyoto.
In the middle of the Heian period (794–1185), samurai improved on the Warabitetō to develop Kenukigata-tachi (ja:毛抜形太刀) -early Japanese sword-. To be more precise, it is thought that the Emishi improved the warabitetō and developed Kenukigata-warabitetō (ja:毛抜形蕨手刀) with a hole in the hilt and kenukigatatō (ja:毛抜形刀) 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).
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 reflect 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. 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. 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. 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.". 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. 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.