Jiri-san Shilsang-saNorth Jeolla Province, Namwon City, Sannae-myeon District 전북 남원군 산내면의 실상산문 (實相山門), 실상사 The Silsang-san school was founded by Master Hongcheok (洪陟; fl. 830), who studied under Zhizang (735-814).
Gaji-san Borim-saSouth Jeolla Province, Jangheung County, Yuji-myeon District 전남 장흥군 유치면의 가지산문 (迦智山門), 보림사 The Gaji-san school was established at Borim-sa under the influence of Doui and his grand-student Chejing (體澄; 804-890). Doui studied in China under Zhizang (735-814) and Baizhang (百丈; 749-814).
Sagul-san Gulsan-sajiGangwon Province, Gangneung City, Gujeong-myeon District 강원도 강릉시 구정면의 사굴산문 (捨堀山門), 굴산사 The Sagul-san school was established by Beom-il (梵日; 810-889), who studied in China with Yanguan Qian (鹽官齊 安; 750-842) and Yueshan Weiyan (樂山惟嚴).
Dongri-san Tae-an-sa South Jeolla Province, Gokseong County / Town, SE Jiri-san area 전남 곡성군 곡성면의 동리산문 (桐裡山門), 대안사 The Dongni-san school was founded by Hyejeol (慧徹; 785-861) who was a student of Zhizang (735-814).
Seongju-san Seongju-sajiSouth Chungcheong Province, Boryeong City, Seongju-myeon District/Town 충남 보령시 성주면의 성주산문 (聖住山門), 성주사 The Seongju-san school was established by Muju Muyeom (無染; 800-888) who received his inga from Magu Baozhe (麻谷寶徹; b. 720?), a disciple of Mazu Daoyi.
Saja-san Heungnyeong-saji (now Beobheung-sa, a Jeokmyeol-bogung site) Gangwon Province, Yeongwol County, Suju-myeon District 강원도 영월군 영주면의 사자산문 (獅子山門), 흥령사 The Saja-san school was established by Doyun (道允; 797-868), student of Nanquan Puyan (南泉普願; 748-835).
Huiyang-san Bongam-saNorth Gyeongsang Province, Mungyeong City, Ga-eun-myeon District 경북 문경시 가은면의 희양산문 (曦陽山門), 봉암사 The Huiyang-san school was founded by Beomnang and also by Chiseon Doheon (智詵道憲; 824-882), who was taught by a Korean teacher of the Mazu transmission.
Bongrim-san Bongrim-sajiSouth Gyeongsang Province, Changwon City, Bongrim-dong District 경남 창원시 봉림동의 봉림산문 (鳳林山門), 봉림사 The Bongnim-san school was established by Weongam (圓鑑; 787-869) and his student Simhui (審希; fl. 9c). Weongam was a student of Zhangjing Huaihui (章敬懷暉; 748-835).
Sumi-san Gwangjo-saji Hwanghae Province (DPRK), Haeju City, Geumsan-myeon District 황해도 해주군 금산면의 수미산문 (須彌山門), 광조사 The Sumi-san school was founded by I-eom (利嚴; 869-936), who studied the Caodong (曹洞) lineage.
Only stonework ruins such as pagodas are left at the Bongrim-san Bongrim- saji, Seongju-san Seongju-saji, Sagul-san Gulsan-saji and Sumi-san Gwangjo-saji. The other sites still host flourishing monasteries where Seon- Bulgyo is enthusiastically taught and practiced by the Jogye Order.
What those familiar with Korean Buddhism call the Nine Mountains (九山; or gusan) are the original homes of the first nine Seon-Bulgyo [Meditational Buddhism; Ch: Chan, Jp: Zen] schools or sects implanted in Korea by nine masters who went to China to study this new radical teaching in the southern region of the Tang Dynasty and then returned to their homeland. They built these nine initial monasteries to spread the Seon that had enlightened them at remote mountains far from the capital city Gyeongju, mostly in the Unified Shilla period of the 8th to 9th Centuries, as central governmental authority and its associated royally-supported scholastic and devotional Buddhist sects were starting to decline. These sites became known as the Gusan-Seonmun 구산선문 or “Nine Mountain Meditation Gates”, through one of which an aspiring monk would trek if seeking attainment of highest clear wisdom.
The initial transmission of Seon into Korea is usually attributed to Master Beomnang (法朗; fl. 632-646), said to be a student of the Chinese master Daoxin (道信; 580-651, regarded as the Fourth Chan "Patriarch"). This was not very successful, however, and Beomnang’s teachings failed to flourish after his death (probably due to lack of royal / aristocratic support), although they may have influenced the philosophy of Great Master Wonhyo-daesa.
Seon-Bulgyo was later popularized in the latter part of the 8th Century and the early 9th Century, especially by Masters Sinhaeng (神行; 704-779) and Do-ui (道義; d. 825). Doui-josa is regarded as its initial founder by the Jogye Order of Korean Buddhism, the unified national sect that inherited and perpetuated the legacies of the Gusan-Seonmun. Recorded legend says that at a meeting of Doui's disciples and other Seon-sect leaders in 826 (one year after Doui's passing) they first proclaimed their unity and first adopted the term Gusan-Seonmun for their school. Eight of these nine sects were of the lineage of Great Chan Master Mazu Daoyi (馬祖道一; 709-788, effectively the "8th Patriarch"), as they were established by monks who attained their inka certification-of-enlightenment directly from him or from one of his eminent disciples.
After this period, there were more than a few Korean monks that studied Chan with the masters of Song Dynasty China and established their own lineage-schools at various mountain monasteries upon their return, leading to the dynamically-burgeoning Korean Seon-Bulgyo of today, but the Gusan-Seonmun are still venerated as the “original” sacred-sites of this sect. The number nine is highly-sacred in all Korean spiritual traditions (along with 3, 5 & 7) and so this number has remained fixed as a cultural- theme of this slice of religious history.
In a Cultural-Geographical analysis, 5 out of these 9 are located to the west of the Baekdu-daegan watershed-dividing mountain-range system that defines Korea's topography, 1 of them relatively close to it and 4 farther them relatively close to it and 1 farther away. Together, 4 of these 9 temples are within the Baekdu-daegan Cultural Region.
Four can be said to be in the western side of Korea, and 5 on the eastern side. However, the southern-most 6 are all west of the Nakdong River, none are east of it. One site lies fairly far from the others in what is now North Korea, the other 8 in South Korea. The southern 8 have a remarkably-even spatial-distribution, excepting the Gyeonggi-do region. However, there is no evidence or indication that any of the distributions reported here were in any way intentional by the site-founders, governments or later Buddhist-history writers.
A slight clustering of 4 of these 9 holy-sites is seen surrounding Jiri-san, Korea's most-sacred mountain; this is probably more than co-incidence.
Of Korea's original Three Kingdoms regions (4th to 6th Centuries CE), 3 of them are in the Goguryeo region (two of those in an area that Shilla conquered and Master Jajang-yulsa sacralized for Buddhism in the 600s, one a Jeokmyeol-bogung site and the other quite near another of those), 3 are in the Shilla region and 3 are in the Baekje Region -- an amazing even distribution of 3-3-3.
Of Korea's modern system of provinces, none of them are in Jeju, North Chungcheong, Gyeonggi, nor any of North Korea's provinces except the 1 in South Hwanghae. 2 are in Gangwon-do, 1 in North Gyeongsang, 1 in South Gyeongsang, 1 in South Chungcheong, 1 in North Jeolla (although just east of the Baekdu-daegan line), and 2 in South Jeolla.