What is the origen of Tibetan style Aceh blade forms?

[josh stout]

In the recent post showing a lovely collection of Aceh weapons (http://www.vikingsword.com/vb/showthread.php?t=4805) there are several examples showing straight backed sabers. The blade form is identical to that of Tibetan sabers. This form was the typical East Asian blade form until the rise of the Mongols in the Yuan dynasty. The form survived relatively unchanged in Tibet. Are the blades from Aceh another example of the old style of Asian saber, or are they an example of "convergent evolution"? The blade shape is so evocative of Tibetan blades with the same tip shape and even, at least in one example I have seen, the same hairpin piled construction. I can think of no way that Tibetan blades could have influenced Aceh, but it seems quite possible that the Aceh blades are another surviving example of a very old style.

This was the blade form that was the ancestor of Japanese blades in the Tang dynasty.
Josh