Seigen was reputed as a master of the Chūjō-ryū style of sword fighting, excelling in the kodachi art.
However, it is not truly known if such information is true, with some rather believing that Kojirō was trained by one of Seigen's students, Kanemaki Jisai.
After he became completely blind, Seigen's lord was wondering if he had actually succeeded, so he ordered a sparring with a disciple of Shintō-ryū called Umezu, fighting with a staff over 3 feet.
As soon as the fight started, Seigen jumped to him and repeatedly struck him with his wooden kodachi, hand, face, torso, everywhere Umezu was beaten wildly and indiscriminately until his head was broken and he fell bloody.
As a blind warrior and using a wooden weapon instead of a Shinken, Seigen had to fight this way, because he couldn't see his opponent's blade and actual state.