Sosan, also known by the Chinese name Sengcan (僧璨), stands in the Zen tradition as a Chinese Chan master who is traditionally regarded as the Third Patriarch after Bodhidharma and Huike. Very little about his life can be established with historical certainty, and most of what is known comes from later Chan records that seek to preserve a sense of spiritual ancestry. Within this remembered lineage, he appears as a monk formed in the ferment of early Chinese Buddhism, receiving the transmission of the teaching from Huike, who in turn had received it from Bodhidharma. In this way, Sosan is placed as a vital link in the chain that connects the Buddha’s awakening, through India, into the emerging Chinese Chan movement. His life, as it is remembered, functions less as a biographical record and more as a symbol of continuity in the unfolding of the Zen tradition.

Sosan is also traditionally associated with the text known as the *Xinxin Ming* (“Faith in Mind” or “Inscription on Trust in the Heart”), one of the earliest and most influential poetic expressions of Chan insight. This work, ascribed to him in the tradition, articulates themes of non-duality, emptiness, and the nature of the enlightened mind, and it has long served as a touchstone for practitioners seeking to understand the Chan approach to reality and practice. At the same time, later scholarship has questioned whether Sosan himself actually composed the text, suggesting that it may have been compiled at a later date; thus his connection to it can be seen as part of the way the tradition gathers its teachings around emblematic figures. Whether or not he was the historical author, the association of Sosan with the *Xinxin Ming* reflects how his image has come to embody a style of direct, non-conceptual pointing to the heart of mind.

His recognition as the Third Patriarch rests above all on the idea of dharma transmission: Bodhidharma to Huike, Huike to Sosan, and Sosan onward to later figures such as Daoxin. This pattern of succession, preserved in early Chan genealogies and later “Transmission of the Lamp” literature, does more than list names; it offers a vision of an unbroken “mind seal,” a living continuity of realization passed from teacher to disciple. In this sense, Sosan is remembered not only as an individual but as a “bridge figure,” carrying the formative impulse of Bodhidharma’s teaching into the soil from which later Chinese Zen would fully flower. His place as Third Patriarch, therefore, is less a matter of verifiable historical detail and more a testament to how the tradition understands the flow of awakening through time: quiet, often hidden, yet transmitted heart-to-heart.