Seinen 靜然 (active c. 1100–1180, traditional dates) was a late-Heian to early-Kamakura Tendai esoteric (Taimitsu 台密) master, resident of the Hōman-in 法曼院 cloister on Mt. Hiei. He is principally known as the compiler of the monumental [[KR6t0409|Xínglín chāo 行林抄]] (82 fascicles in the Taishō edition; T76n2409) — the largest single procedural-encyclopedic Tendai-esoteric reference work, and the principal medieval Taimitsu compendium of deity-specific rites.
The Xínglín chāo (also read Gyōrinshō) systematically presents the procedural-ritual details of approximately three hundred individual deity rites, indexed by deity: Garbhadhātu and Vajradhātu mandalas, then the betsuson 別尊 (individual-deity) rites — Acalanātha, Yamāntaka, gōzanze, the eight Bodhisattvas, the four Heavenly Kings, etc. Each rite is given with its prescribed honzon image, altar arrangement, mudrās, mantras, contemplation sequence, and any kuden variants from the Tani-ryū, Kawa-ryū, and other Taimitsu sub-lineages. The work draws extensively on Chōen’s KR6t0108 Sìshí tiè jué and on the procedural-analytical works of Kakuchō (覺超) and Kōkei (皇慶).
Seinen’s compilation effort is the definitive Hōman-in lineage statement of Tendai-esoteric procedural ritual, and Xínglín chāo remained the principal practical reference for medieval and early-modern Taimitsu masters. His exact lifedates and biographical details are sparsely recorded; the work’s compilation is conventionally placed in the late twelfth century.