Tettō Gikō 徹翁義亨 (Einin 3 → 1295; Ōan 2 / Shōhei 24 / 1369-05-16), Late-Kamakura → Nanbokuchō Japanese Rinzai-Zen master, dharma-heir of 妙超 Shūhō Myōchō (Daitō Kokushi, 1282–1337) and second-generation abbot of Daitoku-ji 大徳寺. Style-name (字) Tettō 徹翁; dharma-name Gikō 義亨. Posthumous title Ten’ō Daigen Kokushi 天應大現國師, with the later additional title Hōun Enmyō Kokushi 法雲圓明國師. Native of Akashi 明石 in Harima 播磨 province (modern Hyōgo).
In the yulu’s memorial nenkō he is praised as the “great-grandson-in-dharma of Xūtáng Zhìyú 虚堂智愚 (1185–1269), true grandson-in-dharma of 南浦紹明 Nanpo Jōmyō (Daiō Kokushi, 1235–1308), and heir of Daitō Kokushi” — fixing his place in the Ō-Tō-Kan 應燈關 transmission. Entered Daitoku-ji as second-generation abbot in Kenmu 5 / 1338-04-15 (建武五年三月二十六日). Also active at Anyō-ji 安養禪寺 in Tajima 但州 province (the Tan’yō Anyō-ji yǔlù opens the present recorded sayings) and at the Tokuzen-ji 徳禪寺 line of Daitoku-ji affiliates. With his contemporary Kanzan Egen 関山慧玄 義玄 (1277–1361) he is one of the two main heirs of Daitō, the line through Tettō remaining anchored at Daitoku-ji while Kanzan’s became the Myōshin-ji line — the two together forming the Ō-Tō-Kan trunk of all later Japanese Rinzai-Zen.