ŌDACHI

An , meaning "big/thick sword", was a type of long Japanese sword. The term ''nodachi'', or "field sword", which refers to a different type of sword, is often mistakenly used in place of ''ōdachi''. It is historically known as ōtachi.^[1]
The character for ''ō'' (大) means "big" or "great". The characters for ''da'' (太) and ''chi'' (刀) are the same as ''tachi'' (太刀), the older style of sword/mounts that predate the katana. The ''chi'' is also the same character as ''katana'' (刀) and the ''tō'' in ''nihontō'' (日本刀 "Japanese sword"), originally from the Chinese character for a knife, ''dāo''.
To qualify as an ōdachi, the sword in question must have a blade length of 3 ''shaku'' (90.9 cm) or more. However, as with most terms in Japanese sword arts, there is no exact definition of the size of an ōdachi.

Contents

Purpose

Production

How to use

Reasons for loss of popularity

External links

Notes

References

Purpose

The purpose of the ōdachi can be categorized as follows:

★ As an offering to a shrine or gods. Some ōdachi were dedicated with prayer to win a war, others were placed in shrines as legendary swords from mythology.

★ As a weapon. From explanations in old texts, such as ''Heike-monogatari, Taihei-ki'' tell us that ōdachi were used by soldiers during battles.

★ As a symbol for an army. Some ōdachi are too long for practical use. They cannot be used in a battle but it is said that they could have been used as a symbol of an army, such as flags and spears.

★ As a trend during a certain period. Some swords were also used for ceremonies.

★ To show the swordsmith's skill.
Most ōdachi were used for the first two reasons.

Production

Ōdachi are difficult to produce because their length makes heat treatment in a traditional way 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 an Ōdachi would be hard as they would almost certainly have to be custom-made. As such, a local government or religious organization would have to fund ōdachi production, as there is no reason for its creation otherwise.

How to use

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 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 him draw it.
Ōdachi swordplay styles focused on downward cuts and different wields than those of normal swords.
The ōdachi's importance died off after the Osaka-Natsuno-Jin war of 1615 (the battle between Tokugawa Ieyasu and Toyotomi Hideyori). Since then it has been used more as a ceremonial piece.

Reasons for loss of popularity

★ Battles in fields did not occur after 1615.

★ The Bakufu government set 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 awesome appearance was suitable for praying to the gods.

External links

★ Pictures of some blades

Notes

1. Matsumura, ''Daijirin'', page 316

References

★ Daijirin, , Akira, Matsumura, Sanseidō, , ISBN 4-385-14009-X