Yóu Zuò 游酢 (1053–1123), zì Dìngfū 定夫, hào Zhìshān xiānshēng 廌山先生, of Jiànyáng 建陽 (Fújiàn). Jìnshì of Yuánfēng 5 / 1082. One of the Chéngmén sì xiānshēng 程門四先生 (Four Masters of the Chéng School: Yáng Shí 楊時, Yóu Zuò, Lǚ Dàlín 呂大臨, Xiè Liángzuǒ 謝良佐). Famous for the Lì xuě 立雪 (“standing in snow”) episode with Yáng Shí — they waited outside Chéng Yí’s door in the snow until he awoke from meditation. Held office to Jiānchá yùshǐ in Jiànzhōng jìngguó 1 / 1101, eventually Zhī Háozhōu in Xuānhé. Author of Yóu Zhìshān jí 游廌山集 KR4d0114 in 4 juǎn (incomplete recension). Sòng shǐ j. 428 (Dàoxué) has his biography. The catalog gives 1045–1115 but CBDB and standard references give 1053–1123 — followed here.