Tantō

A short sword (短刀) is one of the traditionally made Japanese swords  that were worn by the samurai class of feudal Japan. The dates to the Heian period, when it was mainly used as a weapon but evolved in design over the years to become more ornate. were used in traditional martial arts. The term has seen a resurgence in the West since the 1980s as a point style of modern tactical knives, designed for piercing or stabbing.

Description
The is a single or double edged dagger with a length between 15 – (1 Japanese ). The was designed primarily as a stabbing weapon, but the edge can be used for slashing as well. are generally forged in the hira-zukuri (平造) style (without a ridgeline), meaning that their sides have no ridge line and are nearly flat, unlike the shinogi-zukuri (鎬造) structure of a katana. Some have particularly thick cross-sections for armor-piercing duty, and are called.

were mostly carried by samurai; commoners did not generally wear them. Women sometimes carried a small called a  in their, primarily for self-defense. were sometimes worn as the shōtō (小刀) in place of a in a, especially on the battlefield. Before the advent of the combination, it was common for a samurai to carry a  and a  as opposed to a katana and a.

It has been noted that the would be paired with a  and later the katana would be paired with another shorter katana. With the advent of the katana, the was eventually chosen by samurai as the short sword of choice over the. Kanzan Satō, in his book The Japanese Sword, notes that there did not seem to be any particular need for the, and suggests that the may have become more popular than the  due to the  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 inside.

History of in Japan
The production of swords in Japan is divided into specific time periods:
 * Jōkotō (ancient swords, until around 900 AD)
 * Kotō (old swords from around 900–1596)
 * Shintō (new swords 1596–1780)
 * Shinshintō (new new swords 1781–1876)
 * Gendaitō (modern swords 1876–1945)
 * Shinsakutō (newly made swords 1953–present)

Heian to Muromachi periods
The was invented partway through the Heian period. With the beginning of the Kamakura period, were forged to be more aesthetically pleasing, and  and  became the most popular styles. Near the middle of the Kamakura period, more artisans were seen, increasing the abundance of the weapon, and the  style became prevalent in the cities of Kyoto and Yamato. Because of the style introduced by the in the late Kamakura period,  began to be forged longer and wider. The introduction of the Hachiman faith became visible in the carvings in the hilts around this time. The (line of temper) is similar to that of the, except for the absence of , which is  and. and are found to have taken its place.

During the era of the Northern and Southern Courts, the were forged to be up to 40 cm in length, as opposed to the normal one  (about 30 cm) length. The blades became thinner between the and the, and wider between the  and. At this point in time, two styles of 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 curvature shallowed.

Katana originate from sasuga (刺刀), a kind of used by lower-ranking samurai who fought on foot in the Kamakura period. Their main weapon was a long, with the as a spare weapon. In the Nanboku-chō period, which corresponds to the early Muromachi period, long weapons such as were popular, and along with this, the  lengthened, taking its form as the katana.

Momoyama to the early Edo period
Approximately 250 years of peace accompanied the unification of Japan, in which there was little need for blades. In this period, both the katana and were invented, taking the place of the  and  as the most-used pair of weapons, and the number of  forged was severely decreased. Since this period, have often been carved with splendid decorations. Of the and  forged during this period, three masterpieces are called the Three Blades in Japan.

Late Edo period
There were still a few being forged during the late Edo 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 during this age. There were now only predating the Edo period being used in combat;  forged during the late Edo period were not combative weapons.

Meiji to present
Many 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 and  once more, and the number of  in existence increased dramatically. After World War II, a restriction on sword forging caused manufacture to fall drastically. American and European interest in Japanese martial arts since the war created a demand for the outside Japan from the 1960s through the present time.

Blade types



 * Hira (平): A very common form with no, the edge bevels reaching all the way from the edge  to the back  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  blades it is hexagonal). It is extremely common due to the simplicity of its design.
 * Shinogi (鎬): This is the most common type of blade geometry for long swords, but made in this form are very rare, usually created from cut-down blades when a longer sword has been broken.  means the central ridge that runs along the length of the blade between the edge bevels and the body of the blade.
 * feature an extremely long type point, over half the blade's length.
 * Shōbu (菖蒲): A common blade type that is very similar to the, except that it lacks a , the distinct angle between the long cutting edge and the point section, and instead the edge curves smoothly and uninterrupted into the point.
 * Unokubi (鵜首): An uncommon style akin to the, with a back that grows abruptly thinner around the middle of the blade; however, the  regains its thickness just before the point. There is normally a short, wide groove extending to the midway point on the blade.
 * These were shaped in the  or  style, but from about halfway to the tip the back edge was sharpened though this second edge was not particularly sharp. They had a groove running halfway up the blade and were similar to the -style.
 * Kissaki-moroha (切先両刃): A rare blade type with a double-edged point. Unlike the later the tip had a distinct shape unlike any other : the back edge would curve slightly downwards so that the point was lower than the back of the blade whereas other  had the point in line with the back of the blade. Often they had a wide groove in the base half. The most well known historical blade of this type is the  Kogarasu Maru, "Little Crow", one of the National Treasures of Japan.
 * Moroha (両刃): A rare, double-edged type that has a diamond-shaped cross-section. The blade tapers to a point and contains a  that runs to the point.
 * Yoroi tōshi (鎧通し): that have particularly thick cross-sections for armor-piercing duty.
 * Katakiriha (片切刃): An asymmetric form, sharpened only on one side to create a chisel-shaped cross-section.
 * Kubikiri (首切り): A very rare type; the sharpened blade is on the inside curve rather than the outside. It has no sharpened point, making it difficult to use in battle and enshrouding the weapon in mystery. means head cutter. According to one myth, they were carried by attendants of samurai for cutting off the heads of fallen enemies. There are other speculations existing about the '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.
 * Hōchōgata (包丁形): A form that is commonly described as a short, wide, . The  (kitchen knife-shaped) was one of the blade type that the legendary swordsmith Masamune favored.

Mountings ()

 * Aikuchi (合口): The is a  where the  is flush with the mouth of the sheath. There is no handguard.  normally have plain wooden hilts, and many forms of  have  that are made from animal horns.
 * The is a  that features a small handguard.

Other

 * The (also  or ) is a generally short  that is commonly carried in  or  mounts. It was useful for self-defense indoors where the long katana and intermediate  were inconvenient. Women carried them in the obi for self-defense and rarely for  (ritual suicide). A woman received a  as part of her wedding gifts.
 * Fan : The fan is a common  with a blade entirely concealed within a fan-shaped scabbard. The blade was usually low quality, as this  was not designed to be a display piece, but rather a concealed weapon for self-defense.
 * Japanese spearheads were often altered so that it became possible to mount them as . Unlike most blades, had triangular cross-sections.
 * This is also not truly a, though it is often used and thought of as one. were straight, double-edged blades often used for Buddhist rituals, and could be made from 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  may be found made with a vajra (double thunderbolt related to Buddhism).
 * Modern : 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, Camillus Cutlery Company, Spyderco, Severtech, Ka-Bar, SOG Knives, Columbia River Knife & Tool, and Cold Steel. These "American " designs which are often folding knives, 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
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 include:


 * Aikido
 * Aikijutsu
 * Jujutsu
 * Wadō-ryū (both and katana)
 * Koryu bujutsu
 * Ninjutsu
 * Shorinji Kempo
 * Modern Arnis (taking place of dagger)

Popular culture

 * Teenage Mutant Ninja Turtles features knives used by April O'Neil, Leonardo, and Splinter in the 2012 version, and also by the Shredder in the 1990 version and Karai in the 2003 version.
 * The 2012 game Hitman: Absolution enables players to pick up and use a weapon called the 'Agency Tanto Knife' on levels where Agent 47 fights a rogue sect of his employers, the International Contract Agency