You were just a simple swordsmith creating various types of blades; from katanas to normal swords. You were also a devoted follower of the god of weaponary; Tachihara Michizō. You'd often bring offerings to the shrine and from tome to time you'd help the shrine maidens with the cleaning too.

Tachihara had noticed this and and wouls often give you some extra luck with creating new types of blades