Ōdachi

An ōdachi (大太刀?) (large/great sword) is a type of long traditionally made Japanese sword (nihonto) used by the samurai class of feudal Japan. The term nodachi (field sword) refers to the same type of sword.

The character for ō (大) means "big" or "great". The characters for da (太) and chi (刀) are 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 tō in nihontō (日本刀 "Japanese sword"), originally from the Chinese character for a blade, dāo.

Usage
Ōdachi are used as weapons by Shinobi's. They are 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. Ōdachi swordplay styles focused on downward cuts and different wields than those of normal swords. Since Ōdachi is longer and more flexible than a normal Katana the user would certainly benefit from it.