Ryu

"Ryu, I can't seeee!" "Naturally, that's because I'm covering your eyes."

Source: tatoeba (328236)

When Nakanishi became the headmaster of his own ryu, in the later 1700s, he began looking for a way to make swordsmanship less hazardous, concentrating on the improvement of practice equipment.

Source: wiktionary

In these ways, the ryu system differed little from the European custom of apprenticeship. The Japanese ryu were distinctive, however, in that an imparting of the mechanics of the craft, the shoden and chuden (“first and second stages of teachings”), were considered to be only a partial aspect of a student’s education. What really mattered was the sensei’s careful transmission of the metaphysical principles of his ryu to his most promising disciples.

Source: wiktionary

Dave notes that the only people capable of such precise destruction were bone-breakers from an ancient Japanese ryu.

Source: wiktionary