Hata Kōzan 畑黃山 (also 畑栗山 / Hata Risshan; 1721–1804), Edo-period Japanese physician of the gosehōha 後世方派 school (the post-Hàn-positive doctrinal opposition to the kohōha 古方派 of Yoshimasu Tōdō). Author of the Sekiidan 斥醫斷 (KR3eq054 in combined volume), the principal contemporary rebuttal of Tsuruoki Genitsu’s Idan 醫斷 (Yoshimasu Tōdō’s disciple-record). Defended the post-Hàn medical canon (Shénnóng běncǎo, Sùwèn, Língshū, Nánjīng, Sòng formulary tradition) against the Yoshimasu programme’s radical reduction of all medicine to the Shānghán lùn clinical method. Cataloged under 江戶.