Some historians claim that the regime had descended, from Lhasey Tsangma, like the other Khoche tribes that spread in Khengrig Namsum, in which the evidence can be assumed that the Bjoka Khoche ruled between the 9th and 17th centuries AD. An act of the Bjoka Khoche’s power was his turf away from home. Even now, individuals in Bjoka village unfold, with glory, that the Khoche once ruled the Assamese provinces of Kokabari, Rangapani and Gohali.
This is not mistaken: the Khoche’s home, which still stands today, is an indelible proof. While they build one half of the castle of big stone slabs, the other and apparently the much older half is constructed out of small slabs. Local villagers say the Khoche’s Assamese subjects built the latter, probably by his servants (Zapas).
That, Bhutan relinquished its Duar territories to the British in 1865 at the Treaty of Sinchula shows that some of those regions might have originally belonged to the Khoche. Besides Khengrig Namsum and Assam, the Bjoka Khoche controlled parts of Mongar Dzongkhag. Current we can find his heirs as far as Chimong village, which shows that the Khoche ruled parts of Pemagatsel.