Kaisan (開山) is a Japanese term used in reference to the founder of a school of Buddhism or the founder of a temple, literally meaning "mountain opener" or "to open a mountain." Chan monasteries of China and Japan have traditionally been built in mountainous regions, with the name of whatever mountain it has been built upon then fixed upon the monastery as well as the founding abbot.
Buddhism has been practiced in Japan since about the 6th century CE.
Japanese Buddhism created many new Buddhist schools, and some schools are original to Japan and some are derived from Chinese Buddhist schools.
There were a broad range of reform strategies and movements which aimed at positioning Buddhism as a useful partner to a modernizing Japan.
This included clerical reform to tighten discipline as well as reforms concerning doctrine and practice.
Some Buddhists .