Wikipedia
Rujing
Tiāntóng Rújìng (天童如淨; Japanese: Tendō Nyōjo) was a Caodong Buddhist monk living in Qìngdé Temple (慶徳寺; Japanese: Keitoku-ji) on Tiāntóng Mountain (天童山; Japanese: Tendouzan) in Yinzhou District, Ningbo. He taught and gave dharma transmission to Sōtō Zen founder Dōgen as well as early Sōtō monk Jakuen (寂円 Jìyuán).
His teacher was Xuedou Zhijian (雪竇智鑑, 1105–1192), who was the sixteenth-generation dharma descendant of Huineng.
He is traditionally the originator of the terms shikantaza and shinjin-datsuraku ("casting off of body and mind").