Tantō

A tantō (短刀) is one of the traditionally made Japanese swords (nihonto) that were worn by the samurai class of feudal Japan. The tantō dates to the Heian period, when it was mainly used as a weapon but evolved in design over the years to become more ornate. Tantō were used in traditional martial arts (tantojutsu) and saw a resurgence of use in the West in the 1980s as the design made its way to America and is a common blade pattern found in modern tactical knives.

Description
The tantō is commonly referred to as a knife or dagger. The blade is single or double edged with a length between 15 and 30 cm (6-12 inches, in Japanese 1 shaku). The tantō was designed primarily as a stabbing weapon, but the edge can be used for slashing as well. Tantō are generally forged in hira-zukuri style (without ridgeline), meaning that their sides have no ridge line and are nearly flat, unlike the shinogi-zukuri structure of a katana. Some tantō have particularly thick cross-sections for armor-piercing duty, and are called yoroi toshi. Tantō were mostly carried by samurai, as commoners did not generally wear them. Women sometimes carried a small tantō called a kaiken in their obi primarily for self-defense. Tantō were sometimes worn as the shōtō in place of a wakizashi in a daishō, especially on the battlefield. Before the advent of the wakizashi/tantō combination, it was common for a samurai to carry a tachi and a tantō as opposed to a katana and a wakizashi.

It has been noted that the tachi would be paired with a tantō and later the uchigatana would be paired with another shorter uchigatana. With the advent of the katana, the wakizashi eventually was chosen by samurai as the short sword over the tantō. Kanzan Satō in his book The Japanese sword notes that there did not seem to be any particular need for the wakizashi and suggests that the wakizashi may have become more popular than the tantō due to the wakizashi being more suited for indoor fighting. He mentions the custom of leaving the katana at the door of a castle or palace when entering while continuing to wear the wakizashi inside.

Heian to Muromachi
The tantō was invented partway through the Heian period, when it was mainly used as a weapon. With the beginning of the Kamakura period, tantō were forged to be more aesthetically pleasing, and hira and uchi-sori tantō were the most popular styles for wars in the kamakura period. Near the middle of the Kamakura period, more tantō artisans were seen, increasing the abundance of the weapon, and the kanmuri-otoshi style became prevalent in the cities of Kyoto and Yamato. Because of the style introduced by the tachi in the late Kamakura period, tantō began to be forged longer and wider. The introduction of the Hachiman faith became visible in the carvings in the tantō hilts around this time. The hamon (line of temper) is similar to that of the tachi, except for the absence of choji-midare, which is nioi and utsuri. Gunomi-midare and suguha are found to have taken its place. In Nambokucho, the tantō were forged to be up to forty centimeters as opposed to the normal one shaku (about thirty centimeters) length. The tantō blades became thinner between the uri and the omote, and wider between the ha and mune. At this point in time, two styles of hamon were prevalent: the older style, which was subtle and artistic, and the newer, more popular style. With the beginning of the Muromachi period, constant fighting caused the mass production of blades, meaning that with higher demand, lower-quality blades were manufactured. Blades that were custom-forged still were of exceptional quality, but the average blade suffered greatly. As the end of the period neared, the average blade narrowed and the sori became shallow.

Momoyama to the Early Edo Period
Approximately two hundred fifty years of peace accompanied the unification of Japan, in which there was little need for blades. With weapon smiths given this time, both the katana and wakizashi were invented, taking the place of the tantō and tachi as the most-used pair of weapons, and the number of tantō forged was severely decreased. The only tantō produced during this period of peace were copies of others from earlier eras.

Late Edo Period
There were still few tantō being forged during this period, and the ones that were forged reflected the work of the Kamakura, Nambokucho, or Muromachi eras. Suishinshi Masahide was a main contributor towards the forging of tantō during this age. There are now only prehistoric tantō being used in combat.

Meiji to present
Many tantō were forged before World War II, due to the restoration of the Emperor to power. Members of the Imperial Court began wearing the set of tachi and tantō once more, and the number of tantō in existence increased dramatically. After world War II, a restriction on sword forging caused tantō manufacture to fall very low. American and European interest in Japanese martial arts since the war created a demand for the tantō outside Japan from the 1960s through the present time. In the 1980s, manufacturer Cold Steel popularized tactical knives featuring the tantō blade design.

Tantō blade types

 * Shinogi: This is the most common type of blade geometry for long swords, but tantō made in this form are very rare, usually created from cut-down blades when a longer sword has been broken. Shinogi means the central ridge that runs along the length of the blade between the edge bevels and the body of the blade.
 * Hira: A very common tantō form with no shinogi, the edge bevels reaching all the way from the edge (ha) to the back (mune) with no separate flats in between, creating an almost triangular cross-section (the back is ridged, as on most other blade forms, so the cross-section is actually an extremely asymmetrical diamond shape; on shinogi zukuri blades it is hexagonal). It is extremely common due to the simplicity of its design.
 * Shobu: A common blade type that is very similar to the shinogi zukuri, except that it lacks a yokote, the distinct angle between the long cutting edge and the point section, and instead the edge curves smoothly and uninterrupted into the point.
 * Kanmuri-otoshi: These tantō had a single edge and a back that becomes dramatically thinner for the point-most half. They had a shobu style shinogi that extended to the tip of the blade and a groove running halfway up the blade.  It was very similar to the unokubi style tantō.
 * Unokubi: An uncommon tantō style akin to the kanmuri-otoshi, with a back that grows abruptly thinner around the middle of the blade, but in the unokubi zukuri it regains its thickness just before the point. There is normally a short, wide groove extending to the midway point on the blade.
 * Kissaki-moroha: A rare blade type with a double-edged point, often with a wide groove in the single-edged base half. The most well known historical blade of this type is the tachi Kogarasu Maru, "Little Crow", one of the National Treasures of Japan.
 * Osoraku: Osoraku zukuri features an extremely long o-kissaki type point, over half the blade's length.
 * Hochogata: A tantō form that is commonly described as a short, wide, hira. The hochogata was one of the tantō forms that Masamune (an ancient sword smith whose name has become legend) favored.
 * Katakiriha: An asymmetric tantō form, sharpened only on one side to create a chisel-shaped cross-section.
 * Moroha: A rare, double-edged tantō type that has a diamond-shaped cross-section. The blade tapers to a point and contains a shinogi that runs to the point.
 * Kubikiri: Rare tantō with the sharpened blade on the inside curve rather than the outside. One interesting fact about kubikiri is that they have no point, making them difficult to use in battle and enshrouding the weapon in mystery.  Kubikiri can be roughly translated to “head cutter”. According to one myth, they were carried by assistants into battle in order to remove the heads of the fallen enemies as trophies for the warriors to show off during the triumphant return from battle.  There are other speculations existing about the kubikiri’s possible uses.  Perhaps they were used by doctors or carried by high-ranking officials as a badge is worn today.  They could also have been used for cutting charcoal or incense, or used as an artistic tool for pruning bonsai trees.
 * Yoroi toshi or yoroi doshi'': tantō that have particularly thick cross-sections for armor-piercing duty.

Tantō Koshirae

 * Aikuchi: The aikuchi is a tantō koshirae where the fuchi is flush with the mouth of the saya. There is no tsuba on this form of tantō.  Aikuchi normally have plain wood tsuka, and many forms of aikuchi have kashira that are made from animal horns.
 * Hamidashi: The hamidashi is a tantō koshirae that features a small tsuba.

Other tantō

 * Kaiken tantō: The kuaiken (also kwaiken or futokoro-gatana) is a generally short tantō that is commonly carried in aikuchi or shirasaya mounts. It was useful for self-defense indoors where the long katana and intermediate wakizashi were inconvenient. Women carried them in the obi for self-defense and rarely for jigai (suicide). A woman received a kaiken as part of her wedding gifts.
 * Fan Tantō: The fan tantō is a common tantō with a blade entirely concealed within a fan-shaped scabbard. The blade was usually low quality, as this tantō was not designed to be a display piece, but rather a concealable dagger useful for self-defense.
 * Yari Tantō: Japanese spearheads were often altered so that it became possible to mount them as tantō. Unlike most blades, yari tantō had triangular cross-sections.
 * Ken tanto: This is also not truly a tantō, though it is often used and thought of as one. Ken were straight, double-edged blades often used for Buddhist rituals, and could be made from yari (Japanese spearheads) that were broken or cut shorter.  They were often given as offerings from sword smiths when they visited a temple.  The hilt of the ken tantō may be found made with a vajra (double thunderbolt related to Buddhism).
 * Modern tantō:Modern tactical knives have been made by knife makers Bob Lum, Phill Hartsfield, Ernest Emerson, Allen Elishewitz, Bob Terzuola, Strider Knives, Harold J. "Kit" Carson, Benchmade, Spyderco, Severtech, Ka-Bar, SOG Knives, and Cold Steel.  These "American Tantō" designs feature a thick spine on the blade that goes from the tang to the tip for increased tip strength. The handle shape may be altered slightly to provide better ergonomics.

Use in martial arts
Tantō with blunt wooden or blunt plastic blades are used to practice martial arts. Versions with a blunt metal blade are used in more advanced training and in demonstrations. Martial arts that employ the tantō include:


 * Aikido
 * Aikijutsu
 * Jujutsu
 * Koryu Bujutsu
 * Ninjutsu
 * Shorinji Kempo
 * Modern Arnis (taking place of dagger)

Gallery
 Image:Yari tanto.JPG|Edo Period Japanese yari tantō in koshirae. A yari (spear) converted to use as a tantō. Image:Ken tanto.JPG|Antique Japanese ken tantō, double sided "ken" small sword "tantō" in wood mounts "shirasaya". Image:Yari tanto 1.JPG|Edo Period Japanese yari tantō in koshirae. A yari (spear) converted to use as a tantō. Image:Kwaiken tanto.JPG|Japanese kwaiken style tantō. Image:Fan tanto.JPG|Japanese tantō disguised as a fan. Image:Aikuchi tanto.JPG|Antique Japanese Edo period tantō mounted in the aikuchi style. Image:Tanto ww2 police.JPG|Japanese World War II police type tantō. 