Sòng Zhēnqīng 宋真卿, late-Southern-Sòng Yì teacher of the Wùzhōu Dōnglái-school orbit. Per the preface of 徐子東 Xú Zǐdōng to Yì chuán dēng (KR1a0044), the unidentified father “Xú Zǒnggàn” studied successively under 呂祖謙 Lǚ Zǔqiān, 唐仲友 Táng Zhòngyǒu, and Sòng Zhēnqīng — at whose “book-hall” the father saw a Fú-Xī Xiāntiān bā guà diagram on the wall and from that moment dedicated himself to Yì-study.