Kodachi is a Japanese sword shorter than Daito (long sword) and slightly longer than tanto. Its blade is 40 to 65 cm long. Its size allowed the samurai to pull it out very quickly. It was used where movements were restricted, or in a body-to-body attack. Preferred weapon by the samurai, who relied mainly on their speed. Very convenient for protection, therefore called "the sword that is a shield".

During the Edo Period, the Tokugawa Shogunate was also allowed to be worn by non-samurai, usually merchants.

Kodachi, unlike Wakizashi, has a fixed length, also the curve of the blade is larger and the handle is longer.