Can't See the Sword

I have a bitch... Well, no, I have a sword. It's called - Kankan Sword! ! ! Once this sword is released, it has no effect. It mainly depends on the master's strength. Of course, this sword is not completely useless. It has a characteristic - it becomes strong when it is strong, and weak when it is weak. Our story must start after the decline of kendo... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.