Kakuchō 覺超 (960–1034) was Genshin’s (源信) principal disciple and a leading mid-Heian Tendai-Esoteric (Taimitsu 台密) master. He resided at the Keitō-in 雞頭院 cloister in the Tosotsu-dani 兜率溪 (“Tuṣita Valley”) on Mt. Hiei, in the Yokawa precinct, and is known by the sobriquet Tosotsu-no-Sendoku 兜率先徳 (“the former virtuous one of Tosotsu”) used in his disciples’ references to him.
He was the founder of the Tosotsu-dani sub-lineage of Hiei-zan Tendai esoteric practice — one of the principal mid-Heian Taimitsu lineage centers, alongside the Mudō-ji and Hokke-zan lineages. Kakuchō’s doctrinal-ritual project was the systematization of Annen’s procedural records under the analytical framework of the Three Mysteries (sānmì 三密 / sanmitsu — body, speech, mind), making them more accessible to the practitioner.
His six surviving major works in the Kanripo corpus all concern the Tendai esoteric tradition:
- KR6t0097 Tāizàng sānmì chāo (5 fascicles) — Garbha-realm Three Mysteries compendium.
- KR6t0098 Sānmì chāo liàojiǎn (2 fascicles) — Critical examination of the above.
- KR6t0099 Jīngāng sānmì chāo (5 fascicles) — Vajra-realm Three Mysteries compendium.
- KR6t0100 Dōng màn-tú-luó chāo (3 fascicles) — Eastern Maṇḍala compendium.
- KR6t0101 Xī màn-tú-luó jí (1 fascicle) — Western Maṇḍala collection.
- KR6t0102 Wǔxiàng chéngshēn sījì (1 fascicle) — Private notes on the five-aspect body-completion.
Together these works constitute the canonical mid-Heian Taimitsu ritual literature of the Eshin/Yokawa lineage and remained authoritative within the Tendai esoteric tradition through the medieval and Edo periods.
He should be distinguished from the slightly later (12th c.) Tendai kuden master of the same name in the Genshin tradition.