Wúwài Yìyuǎn 無外義遠, shì 瑞巖, Southern Sòng Cáodòng 曹洞 monk, dharma-heir of Tiāntóng Rújìng 天童如淨 (1163–1228). No birth/death dates recorded in DILA (A001475) or in the standard lineage compendia. Held the abbacy at the Ruìyán chánsì 瑞巖禪寺 in Míngzhōu 明州, one of the four monasteries his teacher Rújìng had himself served, and is accordingly styled 瑞巖遠公.
Yìyuǎn’s editorial role is twofold. First, as an attendant-disciple present during Rújìng’s Tiāntóng abbacy, he recorded shàngtáng dharma in juan 2 of Rújìng’s main yǔlù (KR6q0071, T48 n2002A). Second, and more consequentially, after the 1229 Chinese printing of the main yǔlù he assembled a supplementary single-juan collection of twenty shàngtáng fǎyǔ that the main compiler Zǔrì 祖日 had omitted, and in Ninji 2 xīnchǒu 仁治二年辛丑 (1241) dispatched the manuscript to his dharma-brother Dōgen Kigen 道元希玄 (1200–1253) in Japan. Dōgen added his own postface (spring 1241, Kōshō Hōrin-ji in Kyoto) and the supplement was preserved in Japan in manuscript for nearly five centuries. Rediscovered in 1715 at the Déyún 德雲 quarters of Danzhou 丹州 by Manzan Dōhaku 卍山道白, the supplement was then printed together with the main yǔlù as T48 n2002B (KR6q0072 Tiāntóng shān Jǐngdé sì Rújìng chánshī xù yǔlù).
The act of sending Rújìng’s recovered teaching material to Dōgen in 1241 is the principal Chinese-side editorial gesture consolidating the Japanese Sōtō lineage as a legitimate continuation of the Tiāntóng Cáodòng tradition, and Yìyuǎn is accordingly a pivotal figure in the Japanese Sōtō self-understanding despite the thinness of his surviving biography. DILA A001475 notes him also as one of Rújìng’s named fǎsì alongside the Chinese Lùmén Jué 鹿門覺 and Gūchán Yíng 孤蟾瑩.