 After Gennosuke learned of the Hattori Truce's absolvement, Tenzen sent Koshirou to eliminate him.However, when Oboro attempted to stop the fight, Gennosuke used his Dojutsu to turn Koshirou's whirlwind back onto himself and completely destroy Koshirou's eyes.Gradually, Koshirou learns to use his other senses to compensate but still requires some sort of assistance to effectively fight.