Under the provisions of the Anglo-French agreement of January 1896, from the Chinese frontier southwards to the mouth of the Nam Hok the Mekong forms the frontier between the British Shan States on the west and the territories acquired from Siam by France in 1893.
The chief tributaries of the Salween in British territory are the Nam Yu and the Nam Oi or Nam Mwe on the right bank, and the Hsipa Haw on the left.
Below this the only large affluent is the Nam Pawn, which drains all Karenni and a considerable portion of the Shan States, but is quite unnavigable.
Below this are two streams called Nam Ma, one entering on the right bank, the other on the left, at no great distance from one another, but of no great length.
Veritas vult aliter: nam lex stat, rex cadit.
In the cold weather from the right, and then there are no affluents till the Nam Hka comes in on the left.
The next tributary is the Nam Kyek, on the right bank, down the valley of which the railway will reach the Salween.
A little below is the Nam Nang, on the left bank, coming from the Wa country.
Francigenis occidentalibus facile persuaderi poterat sua rura relinquere; nam Gallias per annos aliquot nunc seditio civilis, nunc fames, nunc mortalitas nimis afixerat.
The next important tributary is the Nam Hsim, on the left bank, rising in the latitude of Keng Tang.