The reason I am writing this dissertation is to introduce another side of Zen, Soto, which is completely unknown in the Western world; and at the same time to bring Dogen's teaching to the attention of Western scholars, since it is famous in Japan as the most profound branch of the philosophy of Zen. Unfortunately, none of Dogen' s teaching has yet been translated into English except Masunaga's private publication given above. Therefore I am taking this opportunity to translate and to add a commentary of my own for the better understanding of Dogen as well as the historical survey of the Soto school. Also I have included the research of Bankei, who was in the line of Rinzai, but his distinguished teaching did not appeal to his contemporaries among the Zen Buddhists; rather he was rebuked by the Rinzai School because of his method of teaching Zen. Later the strict Rinzai School became largely connected with the civil authorities and social leaders, but Bankei's lineage died out because of the opposition. Recently Bankei's Zen and his distinguished teaching. method became very important among Japanese Zen scholars and many of them have done careful research on them. I have translated some of his work and briefly wrote his biography to try to introduce Bankei in the English-speaking world. Incidentally Bankei's teaching was introduced by D. T. Suzuki very briefly; thus my attempt is to supplement it and at the same time to contribute some more of it to Western scholarship.