Ōdachi

A Japanese Edo period wood block print of a samurai carrying a nodachi/ōdachi on his back

An ōdachi (大太刀) (large/great sword) was a type of long, traditionally made Japanese sword (nihonto)[1][2] used by the samurai class of feudal Japan. The term nodachi (野太刀, field sword) refers to the same type of sword.[3][4][5]

The character for ō (大) means "big" or "great".[6] The dachi here (太刀) is the same as tachi (太刀, lit. "great sword"), the older style of sword/mounts that predate the katana. The chi is also the same character as katana (刀) and the in nihontō (日本刀 "Japanese sword"), originally from the Chinese character for a blade,[7] dāo.[8]

To qualify as an ōdachi, the sword in question would have a blade length of around 3 shaku (35.79 inches or 90.91 cm); however, as with most terms in Japanese sword arts, there is no exact definition of the size of an ōdachi.

Purpose

Practically speaking, the function/use of most ōdachi fall into the first two categories—as ceremonial objects and cavalry swords. The possible functions of the ōdachi can be categorized as follows:

Production

Nodachi/ōdachi koshirae

Ōdachi are difficult to produce because their length makes traditional heat treatment more complicated: The longer a blade is, the more difficult (or expensive) it is to heat the whole blade to a homogenous temperature, both for annealing and to reach the hardening temperature. The quenching process then needs a bigger quenching medium because uneven quenching might lead to warping the blade.

The method of polishing is also different. Because of their size, Ōdachi are usually hung from the ceiling or placed in a stationary position to be polished, unlike normal swords which are moved over polishing stones.

Acquiring a fully sharpened Ōdachi would be hard as they would almost certainly have to be custom-made.

Method of use

Edo period wood block print showing an ōdachi/nodachi being worn on the back of a samurai.

Ōdachi that were used as weapons were too long for samurai to carry on their waists like normal swords. There were two methods in which they could be carried: One method was to carry it on one's back. However, this was seen as impractical as it was impossible for the wielder to draw it quickly. The other method was simply to carry the ōdachi by hand. The trend during the Muromachi era was for the samurai carrying the ōdachi to have a follower to help draw it.

An exception exists though. The Kōden Enshin-ryū taught by Fumon Tanaka use a special battō technique for "short" Ōdachi allowing to carry it on the waist. It is called Kōden Iai by this martial art style. The secret is to pull out the sheath rather than drawing the blade. Even though this move is also use in other schools, like Yagyū Shinkage-ryū, Shin musō Hayashizaki-ryū and of course, modern Iaidō, only Enshin-ryū seems to use it to improve the Ōdachi drawing speed, the other schools using it with classical katana. The Kage-ryū style also used to draw from the belt, while using blades approximately 2.8 shaku.

Ōdachi swordplay styles focused on downward cuts and different wields than those of normal swords.

Reasons for loss of popularity

The ōdachi's importance died off after the Siege of Osaka of 1615 (the final battle between Tokugawa Ieyasu and Toyotomi Hideyori). Since then, it has been used more as a ceremonial piece.

This loss of popularity is due to the Bakufu government setting a law which prohibited holding swords above a set length (in Genna 3 (1617), Kan'ei 3 (1626) and Shōhō 2 (1645)). After the law was put into practice, ōdachi were cut down to the shorter legal size. This is one of the reasons why ōdachi are so rare. Ōdachi were no longer of practical use, but were still made as offerings to Shinto shrines. This became their main purpose. Due to the amount of skill required to make one, it was considered that their exotic appearance was suitable for praying to the gods.

See also

References

External links

Wikimedia Commons has media related to Nihonto.