Kodachi

Kodachi is a recurring weapon in the series, usually taking the form of a ninja knife or a katana. It is often a low-ranked weapon and provides no special abilities to the user.

Final Fantasy VI
Kodachi is a low-ranked dagger that can only be used by Shadow. It provides 82 Attack, and is Shadow's initial equipment. Additional others can be stolen from Baalzephon.

Final Fantasy Tactics
Kodachi is a low-ranked ninja blade that provides 10 Attack and 5% Defense. It can be bought for 7,000 gil.

Dissidia Final Fantasy
Kodachi is, oddly, a level 22 armor that provides +1 Attack and +17 Defense.