Thread:Chippokenabokura/@comment-5780397-20170509234835/@comment-26229461-20170526091805

Sorry it took me so long to reply!

You're right, I don't think sheathing/unsheathing Kogetsu has come up when it comes to Senkuu. The only place it's mentioned is in the Q&A where Ashihara talks about turning Kogetsu off to use other triggers, which would leave it just a stick so people sheath it to keep it out of the way.

In ch154 it just says the speed of the sword needs to be very fast and match the timing of Senkuu perfectly because Ikoma only activates Senkuu for 0.2 seconds.