The  Seonjong Gusan
[9 Holy Zen-sect Buddhist Mountains]
Homes of the  Gusan-Seonmun  구산선문  Temples  
Jiri-san  Shilsang-sa                 North 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-sa                  South 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-saji             Gangwon 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-saji      South 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-sa        North 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-saji     South 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 Yi-eom Jincheol Daesa (利嚴 眞澈 大師; 869-936), who was enlightened
in the Caodong (曹洞) lineage.

Only stonework ruins such as pagodas are left at the Bongrim-san Bongrim-
,  Seongju-san Seongju-saji,  Sagul-san Gulsan-saji  and  Sumi-san
.  The other sites still host flourishing monasteries where Seon-
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
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
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.