Prajnaparamita in Eight Thousand Verses Tibetan Translation Chapter 9
Tsari (tsa ri), one of the three most important sacred mountains of Tibet, the other two being Tise (ti se) and Lapchi (la phyi). These three mountains are listed among the gnas chen nyi shu rtsa bzhi, the "24 Sacred Places of the World" and are often called the "Three Holy Mountains of Tibet". Tsari is situated on the border of Tibet and the northern Indian state of Arunchal Pradesh.
Even though Tise, or Mount Kailash as it is more commonly known, is certainly the most famous of these three, it is interesting to note that the great 4th Gyalwang Drukpa Pema Karpo (pad ma dkar po 1527-1592) considers Tsari, in his guide (gnas yig) to the place, as the most important. All three mountains are considered to be the mandala of Chakrasamvara and his consort Vajravarahi. Tsari is a place of particular importance to the Kagyu lineages and they were responsible for the "opening" of Tsari and established many monasteries and retreat facilities there.
Even though Tsari was visited already in earlier periods, it took until the 12th century until it was made accessible for the broader public. As we know from Pema Karpo's guidebook, the first human visitors to Tsari were Guru Padmasambhava and Vimalamitra. They entered Tsari through the "southern door". In the 10th century, they were followed by the Indian Mahasiddha Lavapa, one of the teachers of the great Atisha, and his disciple Bhusuku. They entered through the "eastern door". In the 12th century Kyebu Yeshe Dorje (skyes bu ye shes rdo rje), a disciple of Gampopa, followed. He tried to reach Tsari three times. On his third attempt he was successful and entered through the "western door". It was also him who opened the door to the so-called "Turquoise Lake" (g.yu mtsho) in Tsari.
Then Tsangpa Gyare Yeshe Dorje (gtsang pa rgya ras ye shes rdo rje 1161-1211), one of the founders of the Drukpa Kagyu tradition, came to Tsari after he had a vision of Gyalwa Lorepa (rgyal ba lo ras pa 1187-1250), telling him to go there. Tsangpa Gyare entered the region through the "north-western door". Sonam Gyaltsen (bsod nams rgyal mtshan 1181-1261) of Ralung (rwa lung) followed and was the first to enter Tsari through the "northern door".
As we know from the biography of the founder of the Drikung Kagyu lineage, Drikung Kyobpa Jigten Sumgon ('bri gung skyob pa 'jig rten gsum mgon 1143-1217), he had a dream in which he was visited by the protectors of Tsari, Tise and Lapchi, requesting him to come and bless their places. Jigten Sumgon was unable to go himself, but he promised to send many great practitioners. The first of these was Nyo Lhanangpa (gnyos lha nang pa 1164-1224), one of his foremost disciples. Many others followed later.
A detailed account of Tsari and its features can be read in English in Matthieu Ricard's translation of the autobiography of Shabkar Tsogdruk Rangdrol (zhabs dkar tshogs drug rang grol 1781-1850), "The Life of Shabkar", chapter 10, "The Ravines of Tsari"; and in Toni Huber's "The Cult Of Pure Crystal Mountain".