In understanding the history of early Zen-sect, the issue of Zen Dharma of Dao-xin道信 and his genealogy are very important. Recently, there often has been a tendency to conclude the character of Zen Dharma of Dao-xin and deny historical evidence easily, by reasoning from a mere assumption and distortion. This tendency is due to not having the profound understanding on the Zen Dharma in early Zen-sect, and it must be considered with caution. The present writer pointed it out in the part I and II section of this thesis. The Zen Dharma of Dao-xin succeeded to Lanka-Zen of early Zen-sect as the way it is, since the great monk Dharma. I made it clear that the Lanka-Zen should not be distinguished from the Prajna-Zen, and such classified terms of Zen Dharma are not suitable for actual Zen Dharma. The practice of vipaśyanā to mind(看心) and the practice of transcendence of vipaśyanā(絶觀) ･ the practice of non-watch(不觀) ･ the practice of non-thinking(不思) ･ the practice of non-practice(不行) are not heterogeneity in Zen Dharma. This Zen Dharma can not be divided into gradually realizing Dharma and directly realizing Dharma, but directly realizing Dharma has this Zen Dharma as a chain of practice system. The profound meaning of Zen Dharma can be understood better through directly realizing Dharma advocated by Zen-master Mahayana摩訶衍禪師 in 'Disputation in Tibet (792-794)'. The issue of the relations between teacher and pupil of Dao-xin and Niu-dou Fa-long牛頭法隆 also can not be determined by simple view point from documents criticism. And it is necessary to give consideration to the peculiar way of Zen-Sect. I'm sure that the result of this thesis will correct the former fixed ideas on the Zen Dharma of Southern and Northern Zen-Sect.

In understanding the history of early Zen-sect, the issue of Zen Dharma of Dao-xin道信 and his genealogy are very important. Recently, there often has been a tendency to conclude the character of Zen Dharma of Dao-xin and deny historical evidence easily, by reasoning from a mere assumption and distortion. This tendency is due to not having the profound understanding on the Zen Dharma in early Zen-sect, and it must be considered with caution. The present writer pointed it out in the part I and II section of this thesis. The Zen Dharma of Dao-xin succeeded to Lanka-Zen of early Zen-sect as the way it is, since the great monk Dharma. I made it clear that the Lanka-Zen should not be distinguished from the Prajna-Zen, and such classified terms of Zen Dharma are not suitable for actual Zen Dharma. The practice of vipaśyanā to mind(看心) and the practice of transcendence of vipaśyanā(絶觀) ･ the practice of non-watch(不觀) ･ the practice of non-thinking(不思) ･ the practice of non-practice(不行) are not heterogeneity in Zen Dharma. This Zen Dharma can not be divided into gradually realizing Dharma and directly realizing Dharma, but directly realizing Dharma has this Zen Dharma as a chain of practice system. The profound meaning of Zen Dharma can be understood better through directly realizing Dharma advocated by Zen-master Mahayana摩訶衍禪師 in 'Disputation in Tibet (792-794)'. The issue of the relations between teacher and pupil of Dao-xin and Niu-dou Fa-long牛頭法隆 also can not be determined by simple view point from documents criticism. And it is necessary to give consideration to the peculiar way of Zen-Sect. I'm sure that the result of this thesis will correct the former fixed ideas on the Zen Dharma of Southern and Northern Zen-Sect.

Dao-xin(道信), the practice of vipaśyanā to mind(看心), the practice of transcendence of vipaśyanā(絶觀), the practice of non-watch(不觀), the practice of non-thinking(不思), the practice of non-practice(不行), Zen-master Mahayana(摩訶衍禪師), disputation in Tibet(티베트종론), Niu-dou Fa-long(牛頭法融), gradually realizing Dharma(漸法), directly realizing Dharma(頓法)