Longtan Chongxin

Longtan Chongxin (龍潭崇信, fl. early 9th c.) was a Dharma heir of Tianhuang Daowu and the teacher of Deshan Xuanjian, occupying the decisive middle position in the Shitou → Tianhuang → Longtan → Deshan → Xuefeng line through which the Yunmen and Fayan houses descend^[1]. The lamp records emphasise his humble origins: before ordination he was a rice-cake seller near Tianhuang's temple, and the transmission they describe matured slowly through daily interactions rather than through any single dramatic exchange^[2].

His most celebrated teaching moment is the encounter preserved in the *Wúménguān* and the *Jǐngdé Chuándēng Lù* with Deshan Xuanjian, who had come south as a *Diamond Sūtra* scholar intending to refute the Southern School. When Deshan asked for more light to find his way along a dark corridor, Longtan lit a paper candle, handed it to him, and immediately blew it out — and at the moment of sudden darkness Deshan is said to have undergone his decisive awakening^[3].