Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. AN dachi , meaning "great big 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 dachi. IT is historically known as tachi. THe character for means "big" or "great". THe characters for da and chi are the same as tachi ( lit. "big sword"), the older style of sword/mounts that predate the katana. THe chi is also the same character as katana and the t in nihont ( "Japanese sword"), originally from the Chinese character for a knife, d o. TO qualify as a dachi, the sword in question must have a blade length over 3 shaku (a little under a metre). REgardless of size, most dachi have religious inscriptions on the tang. HOwever, as with most terms in Japanese sword arts, there is no exact definition of the size of an dachi.