Odachi

From Karate, Kungfu, Wrestling, Mixed Fighting Information Source

An ōdachi or "big/thick sword" was a type of long Japanese sword. The term nodachi (野太刀 "field sword"), which refers to a different type of sword, is often mistakenly used in place of ōdachi.

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.

The odachi has been used in various ways, but generally it was utilized as a ceremonial object. The odachi is mark of a swordsmith's skill and because of this, it was usually offered to the gods by placing it on a shrine as a sign of gratitude. Some ōdachi are too long for practical use. And because of their enormous size. 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.