Jimon and Sanmon

Jimon (寺門) and Sanmon (山門), also known as the Enchin and Ennin factions, respectively, were rival branches of the Tendai sect of Buddhism created in the 9th century and based on Mount Hiei just outside Kyoto.

Jimon's head temple was Mii-dera, at the foot of Mount Hiei, while the Sanmon sect was based at Enryaku-ji, at the summit of the mountain.

The origins of the schism began with a rivalry between the lineages of two disciples of the founder of Tendai Buddhism, Saicho, named Ennin and Enchin, over who would be the zasu (座主, "abbot") of Enryaku-ji temple, rather than based on differing opinions on dogma or doctrine.

Monks of the Enchin lineage were driven out of Enryaku-ji and moved down the mountain to Mii-dera forming the jimon (寺門, "Temple Gate") faction, while the monks of the Ennin lineage who remained at Enryaku-ji formed the sanmon (山門, "Mountain Gate") faction.

[1] Along with other major temples in the capital, both sects formed the first standing armies of warrior monks, called sōhei.