Tettsu Gikai

Tettsu Gikai was the third abbot of Eiheiji and a pivotal figure in the early Soto school. His tenure was marked by controversy—he introduced ritual elements and institutional changes that some of Dogen's other students viewed as departures from the founder's austere vision. This conflict eventually led to Gikai's departure from Eiheiji and the establishment of a separate lineage stream.

Despite the controversy, Gikai's contribution to the Soto school was significant. His student Keizan Jokin would become the "Great Popularizer" who made Soto Zen accessible to a broad Japanese audience, founding Sojiji Temple and integrating elements of esoteric Buddhism and folk religion into Soto practice. Through Keizan, Gikai's lineage became the numerically dominant branch of Japanese Soto Zen.