This study treats violent actions by Buddhist groups in premodern Japan (ca. 6.-17. ces.). When Buddhism was introduced from Korea since the 6. ce., it triggered conflicts with the indigenuous beliefs. They consisted of physical war between different clans and spiritual warfare through subjugation of the local deities. Later, after Japanese Buddhism had developed into various denominations since the 8. ce., sectarian conflicts for patronage among competing Buddhist groups emerged which the state had to control. When during the late Heian period, struggles about the ownership of landed estates emerged, the aristocats employed warriors for their protection whereas monasteriesguarded their manors through low ranking “evil monks”. Because they injured and killed people in order to fullfil their duties, scholar monks developed doctrinal justifications to exculpate them against critics. When during the Kamakura period new Buddhist groups emerged, the established monasteries used their monastic armees as well as the military of the state to subdue them because they threatened their economic and social basis. Finally, during the Muromachi period violent peasant uprisings of a new Buddhist group were triggered by its suppression through a monastic complex due to economic reasons, i.e. competiton concerning membership and donations.