In old days, it was used for shiho (to inherit the dharma from a priest master) priestly teacher, but now it is a common name for those who preside a So-do Hall (A training hall for meditation) and are entitled to give inka (permission) to ascetic monks who reached Gotatsu (comprehension, understanding, Buddhist enlightenment, satori).
古くは一般に嗣法の師僧をさす呼び名だったが、現在では修行道場である僧堂を主宰し、悟達の修行僧に印可を与える資格を有する者をいう。