Four Sword Style

Yontoryu (四刀流) is a sword technique developed and used by Kaku.

Overview
As the technique's name suggest, Yontoryu is swordsmanship that uses four swords. Kaku achieves this by combining his two shirasaya katana with his Rokushiki technique "Rankyaku", which is to create slicing air blades via kicking, thus appearing to have four blades in total. Kaku's large variation in the Rankyaku technique makes the Yontoryu a truly powerful and versatile combat style. The most prominent example of combining his two swords with his Rankyaku is the "Rankyaku: Ran", where he used the two blades to stay on the ceiling while raining a flurry of air blades down at his opponent.

Upon consuming the Ushi Ushi no Mi, Model: Giraffe, Kaku further attained versatility with his Yontoryu style, by combining the increase in size and strength that he gains from transforming into a giraffe-human hybrid. His long neck also serves as a whip of sort, which he functions somewhat like a blade.