Accounts of Sosan’s life, though sparse and partly legendary, consistently portray a teacher whose path unfolded under considerable strain. Traditional sources remember him as living in a time when Buddhism was periodically suppressed, with imperial policies turning against the Dharma. In response, he is said to have withdrawn into the mountains, teaching in seclusion and moving from place to place rather than establishing a visible, public community. This reclusive, almost hidden existence suggests that his role as a patriarch was carried out under the shadow of political danger, rather than in the security of an established monastery.

Another thread running through these accounts is the description of serious illness, often depicted as a debilitating skin disease. Such a condition would not only have brought physical suffering but also social marginalization, placing him at the edges of conventional society. Within the Zen tradition, this bodily affliction is sometimes seen as a stark backdrop to teachings that emphasize non-attachment and the insubstantiality of the self. His authority as a teacher, then, did not arise from worldly prestige or physical vigor, but from a realization that was tested against frailty and vulnerability.

The combination of persecution and illness appears to have shaped the very form of his teaching activity. Rather than presiding over a large, institutional sangha, Sosan seems to have worked in relative obscurity, transmitting the Dharma in a more intimate, master-to-disciple manner. The fact that later records preserve only limited details of his life and community suggests that external pressures constrained the visibility of his work, even as the lineage itself continued. From this perspective, his legacy illustrates a mode of Zen transmission that flourishes quietly, almost anonymously, under adverse conditions, bearing witness to a practice that does not depend on favorable circumstances to endure.