Kyōjin 經尋 (active late 12th to early 13th century, conventional lifedates uncertain) was a late-Heian to early-Kamakura Japanese Shingon scholastic, known by his cloister-name Hōjō-bō 寶生房 (“the Ratnasaṃbhava cloister”). He is principally remembered for his KR6t0151 Zhēn-yán jiào-zhǔ wèn-dá chāo 眞言教主問答抄 (“Question-and-Answer Compendium on the Teaching-Master of the Mantra Tradition”), a one-fascicle doctrinal Q&A treatise on the contested medieval Shingon question of which Buddha-body teaches the Esoteric scriptures.
The work addresses the doctrinal-disputational question that runs through medieval Shingon scholasticism — whether the Mahāvairocana-sūtra and Vajraśekhara-sūtra are discoursed by (a) the svabhāva-kāya / Mahāvairocana-as-dharmakāya, (b) the saṃbhoga-kāya / self-enjoyment Mahāvairocana, or (c) all four bodies acting simultaneously — and surveys the principal positions of medieval Shingon authorities on this question.
Kyōjin is sparsely documented in the standard biographical sources beyond his attested authorship of this text.