Bonan belt knife
 

A bonan belt knife with its original retention thong.
This style typically has a diamond shaped handle crossesction .
The blade is asymmetrical.
The bonan seem to make more than a dozen very distinct styles if knife . And make many specific types preferred by different ethnic groups that they trade with.
I was surprised to see the bonan had replaces Tibetan blacksmiths in many Tibetan towns and would produce Tibetan products, but not Tibetan style knives which the Tibetans seem to buy from Tibetan makers. But they would supply the bonan types of knife..