When you do certain things often enough, they just... stay with you!

[She beams, obviously delighted; the truth of the matter is, cooking is one of the other ways she can feel connected to the Shinsengumi even though chances are she'll never see any of them again. When she prepares a meal, it brings back so many memories of preparing meals for those men.

But that, too, is part of the bargain. Her brother's safety in exchange for the life she used to lead.]

I'm sure it's the same with Yukimura-san. Maybe not cooking, but even so... everyone has at least one skill like that.