Sensa, Sensou

Flash sheathe and flash step. Unique space-utilization techniques passed down by the Nanaya, that make use of the walls and ceiling to move. Sensa refers to the arm techniques, while Sensou refers to the leg techniques.
As a member of the Nanaya bloodline, these come quite naturally to Nanaya Shiki, but it seems Tohno Shiki can also pull off similar movements when he's been backed into a corner. In fact, it could probably be called Shiki's trump card.
Also, as the name of Nanaya Shiki's Last Arc, Kyokushi Nanaya, suggests, it is the ultimate technique of the Nanaya family. It was first demonstrated in Kagetsu Tohya.

MB Act Cadenza PS2 Manual: Tsukihime Dictionary