Sandai sōron

The sandai sōron (三代相論), or third-generation differentiation, was a putative dispute over the orthodoxy and succession of Sōtō Zen Buddhism. The major figures involved were Jakuen, Gikai, Gien, and Giin, all of whom claimed the right to serve as abbot of Eihei-ji. The story of the sandai sōron does not appear until 150 years after it supposedly occurred, suggesting its authenticity is dubious. It seems to have been used as a just-so story to explain how Jakuen's line eventually wound up in control of Eihei-ji. The obscure term sōron (相論, a translation of the Sanskrit laksana) may have been a euphemism for a third-generation schism.

Historical context

Sōtō's founder Dōgen named Koun Ejō as his successor, but Ejō did not name a definite successor. The four monks who received dharma transmission from Ejō all made claims of friendship with Dōgen and Ejō, with various levels of honesty, and adherence to the principles of Sōtō, which were interpreted in varying ways.

It is clear that Jakuen voluntarily left Eihei-ji by himself. His monks at first remained behind, possibly contributing to the fragmentation of Jakuen's line.