The Fourth Tai Situ, Mitruk Chokyi Gocha (si tu 04 mi 'khrugs chos kyi go cha) was born in a place called Zurmang Tsigyu (zur mang rtsi rgyud) in 1542. The Eighth Karmapa, Mikyo Dorje (karma pa 08 mi skyod rdo rje 1507-1554) recognized him as the reincarnation of the Third Situ, Tashi Peljor (si tu 03 bkra shis dpal 'byor 1498-1541) and enthroned him at Karma Gon (karma dgon) monastery, the initial seat of the Tai Situ incarnation line.
He received teachings and transmissions from the sutras and tantras from seven masters including the Eighth Karmapa. The Karmapa gave him the title Vajra Holder (rdo rje 'chang) and gave him the name Situ Mitruk Chokyi Wozer Gocha (si tu mi 'khrugs chos kyi 'od zer go cha). He renovated Yermoche Monastery (g.yer mo che dgon) and provided for monks there.
He played a major role in recognizing the Ninth Karmapa, Wangchuk Dorje (karma pa 09 dbang phyug rdo rje 1556-1603), and is said to have been involved in the recognition of the Sixth Zhamar, Chokyi Wangchuk (zhwa dmar 06 chos kyi dbang phyug 1584-1630), although this might not have been possible. He spent the later years of his life in retreat.
According to the Eighth Tai Situ, Chokyi Jungne, Mitruk Chokyi Gyatso was the first Situ incarnation to wear a black hat in the shape of the five buddha families; the previous Situ incarnations wore a black three-petaled lotus black hat.
The year of his death is not certain. Some sources list 1585, but this can not be the case if the Fifth Situ, Chokyi Gyeltsen (ta'i si tu 05 chos kyi rgyal mtshan, 1562/1586-1632/1657) was born in 1562. It is more likely that Chokyi Gocha passed away in the later years of the 1550s or the early 1560s.
Bibliography
Chos kyi byung nas. 1968. tA'i si tur 'bod pa karma bstan pa'i nyin byed kyi rang tshul drangs por brjod pa dri bral shel gyi me long. New Delhi: International Academy of Indian Culture, p. 34. TBRC W00KG09387.
Grags pa 'byung gnas and Blo bzang mkhas grub. 1992. Gangs can mkhas grub rim byon ming mdzod. Lanzhou: Kan su'u mi rigs dpe skrun khang, p. 1758. TBRC W19801.
Jackson, David. 2009. Patron and Painter. Situ Panchen and the Revival of the Encampment Style. New York: Rubin Museum of Art, pp. 33-34; 78.
Karma rgyal mtshan. 1997. Kam tshang yab sras dang dpal spungs dgon pa. Phu rdzong: Si khron mi rigs dpe skrun khang, pp. 83-84. TBRC W27303.
Si tu pan chen chos kyi 'byung gnas. 1972. Sgrub brgyud karma kaM tshang brgyud pa rin po che'i rnam par thar pa rab byams nor bu zla ba chu shel gyi phreng ba, vol. 1, pp. 1-700. New Delhi: D. Gyaltsan & Kesang Legshay, p. 63. TBRC W23435.