Tanto

A tantō (短刀, tantō? "short sword") is a common Japanese single or, occasionally, double edged knife or dagger with a blade length between 15 and 30 cm (6-12 inches). The tantō was designed primarily as a stabbing weapon, but the edge can be used for slashing as well. Tantō first began to appear in the Heian period, however these blades lacked any artistic quality and were purely weapons. In the early Kamakura period high-quality artistic tantō began to appear, and the famous Yoshimitsu (the greatest tantō maker in Japanese history) began his forging.

Tantō production increased greatly around the Muromachi period and then declined in the Shintō period ("new sword" period). Consequently, Shintō period tantō are quite rare. They regained popularity in the Shin-Shintō Period ("new-new sword" period) and production increased.

Tantō are generally forged in hira-zukuri, 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 yoroidoshi.

Tantō were mostly carried by samurai as commoners did not generally carry them. Women sometimes carried a small tantō called a kaiken in their obi primarily for self defense.
It was sometimes worn as the shōtō in place of a wakizashi in a daisho, especially on the battlefield. Before the 16th century, it was common for a samurai to carry a tachi and a tantō as opposed to a katana and a wakizashi.

Tantō with blunt wooden or blunt plastic blades exist and are used to practice martial arts involving the use of a tantō safely. Versions with a blunt metal blade are used in more advanced training or demonstrations. Martial arts that include techniques with tantō include:

Aikido
Aikijutsu
Jissen Kobudo Jinenkan (Jinen Ryu Tantojutsu)
Bujinkan Budo Taijutsu
Genbukan Ninpo Taijutsu
Jujutsu
Koryu Bujutsu
Shorinji Kempo
Modern Arnis (taking place of dagger)

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