Foundation of the Nine Mountain Schools
In Korea, Zen was first introduced by the monk Toui. He, a native of Sil Lah, went to China (during the Tang Dynasty) in 784 and returned in 818 after a stay of thirty four years.
Toui was born at a time when Buddhist culture in Sil Lah had already passed its zenith and was entering a period of decline. Toui’s lifetime also happened to coincide with the golden age of Zen Buddhism in China (roughly the 8th and 9th century).
During his stay in China the monk Toui studied under the renowned Zen Master Hsi Tang Chih Tsang (735-814). Along with Nan Chuan (748-835) and Pai Chang (720-814) Hsi Tang was considered to be one of the ablest of the 139 Dharma heirs of the great patriarch Ma Tsu (709 788).
From this Zen Master Hsi Tang Chih Tsang (kor. Seo-Dang Ji-Jang) the monk Toui received the »Transmission of Dharma«. Toui’s enlightenment was also recognized by Pai Chang, who is said to have praised him by saying: »It seems that the orthodox Zen tradition of Zen Master Ma Tsu will soon leave China and cross the sea to Sil Lah«.
Simultaneously with Toui there were a number of Korean monks, who also studied Zen in Tang China. These monks later returned to Sil Lah and founded their own schools and temples. Following the Chinese tradition of the Tang era these founder monks established their temples in the mountains hence they were called »Mountain Schools«. Especially nine of these Mountain Schools were famous, the Nine Mountain Schools, which were all established within a period of one hundred years after Toui’s return from China (between 828 and 931).
In sharp contrast to the Zen Buddhism, that Toui and the other founder monks brought from China, Korean Buddhism had been, up to that time, completely sutra oriented. So, for example, Ui Sang’s Hwa Om School (School of the Avatamsaka Doctrine) had become the most prosperous and most influential sect of all the Doctrinal Schools and therefore exercised the greatest influence on the scholastic orientation of the Sil Lah Buddhism.
In this situation the monk Toui became the first Zen Master in Korea to openly challenge the supremacy, indeed even the validity, of the Doctrinal Schools. During the next hundred years the distinction between Zen and the Doctrinal Schools came to be more sharply drawn in Korea than it had ever been in China.