Wikipedia
is a concept of modulation and movement applied in a wide variety of traditional Japanese arts. Roughly translated to "beginning, break, rapid", it essentially means that all actions or efforts should begin slowly, speed up, and then end swiftly. This concept is applied to elements of the Japanese tea ceremony, to kendō and other martial arts, to dramatic structure in the traditional theatre, and to the traditional collaborative linked verse forms renga and renku (haikai no renga).
The concept originated in gagaku court music, specifically in the ways in which elements of the music could be distinguished and described. Though eventually incorporated into a number of disciplines, it was most famously adapted, and thoroughly analysed and discussed by the great Noh playwright Zeami, who viewed it as a universal concept applying to the patterns of movement of all things.