Sen-I-Soshitsu

Sen-I-Soshitsu (lit., Fiber Stripper, Fiber Rend) is a technique utilized by Ryuko Matoi in conjunction with her Kamui, Senketsu. it was specifically designed to be used against opponents wearing Life-Fiber enhanced clothing. It has seen a great deal of use by the two during the Grand Combat, though in a heavily altered form.

Basic Principle
Sen-I-Soshitsu has three main components- a lightning-fast slice with Ryuko's Scissor Blade, a brief delay, and the total failure of the target's wardrobe. It is exceptionally potent against enemies in power armor, as it simultaneously leaves them humiliated and disarmed.

True Sen-I-Soshitsu vs. False Sen-I-Soshitsu
There has been some debate over whether Ryuko's use of Sen-I-Soshitsu is actually the original attack in anything but name. As Hermione pointed out, the original Sen-I-Soshitsu attack was named for its absorbtion of Life Fibers; thus, using the attack against opponents with no Life Fibers is not really a Sen-I-Soshitsu. It is likely that Ryuko might just enjoy shouting the attack's name.