Chūsan 忠算 — Late-Heian / early-Kamakura Japanese Hossō 法相 (Yogācāra) monk; Saidai-ji 西大寺 bettō 別當 (chief administrator), and one of the principal transmitters of the Zenju 善珠 line of Yogācāra scholarship into the Kamakura period. He bears the by-name Shōshitsu Chūsan 松室忠算 in the Edo-period preface to his canonical work.
His sole surviving canonical work is Sìfēn yì jílüè sījì 四分義極略私記 (KR6t0018, T71n2322), a two-fascicle compressed sub-commentary on Zenju’s KR6t0017 Wéishí fēnliàng jué, treating the doctrine of the four divisions of consciousness. The work entered the Edo Hossō curriculum through the 1750 Kan’en reprint by Genki 賢基, which corrected an earlier printed edition.
He should not be confused with Chūzan 仲算 (935–976, the famous Kōfuku-ji Yuima-e debater), with whom he is often confused in the secondary literature: the two are different persons, written with different characters (忠 vs 仲).
DILA Buddhist Person Authority A000625 records him solely through this canonical attribution and the bettō title; no further biographical detail is recoverable.
Works:
- KR6t0018 Sìfēn yì jílüè sījì 四分義極略私記 (T71n2322), 2 fasc.