Tachikawa-ryū

The was a branch of Shingon Buddhism founded in the early 12th century by Ninkan (仁寛, died 1114), a monk of the Daigo-ji lineage of Shingon who was exiled in 1113 to the province of Izu (part of modern Shizuoka Prefecture) after being implicated in a plot to assassinate the then reigning emperor of Japan, Emperor Toba.

During the late medieval period, the Tachikawa-ryū became notorious after monks of other Shingon lineages accused it of practicing heterodox rites involving sexual intercourse and skull worship, which contributed to its decline and subsequent dissolution during the Edo period. As many of the sect's documents were either lost or destroyed, for a long time knowledge of the Tachikawa-ryū was mostly limited to the writings of its opponents, and both scholarly and popular treatments of the sect took the polemics levelled against it by these authors more or less at face value. In recent years, however, its reputation has begun to see something of a rehabilitation after some advocated a reevaluation of the sect, its actual nature, and its role and impact in medieval (and later) Japanese Buddhism. These scholars argue that the term 'Tachikawa-ryū' actually encompasses a number of different groups not necessarily related to one another, and that the sexual rituals attributed to it was actually practiced by another group distinct from the lineage established by Ninkan.