One of the Noh small hand drum (kotsuzumi) schools, also known in the past as the Kō Seijirō School. After Gorō-jirō Masayoshi (1539-1626), the second-generation master of the kotsuzumi-kata Kō School, eldest grandson Seijirō Satoyoshi (1599-1661) was too young to succeed, so Masayoshi’s second son, Kozaemon Kazumune, took over as the third generation. As a result, Seijirō gradually became the head of a separate family and later founded the Kō Seijirō School (Kōsei School). During the Edo period, this mainly served as the musical accompaniment for the Kanze School. The playing style is similar to that of the Kō School due to its founding history but is characterized by having more grace rhythm patterns (tegumi). Today's performers are mainly active in Tokyo and Nagoya.