Join Date: Dec 2004
Location: Little House on the Prairie
As Robert indicates, this is from northern Burma and neighboring NE India. These dao are actually of Kachin (sometimes also called Lisu, Jingpaw) origin and the Naga tribes simply "acquired" them through battle pickups or perhaps trade with the Kachin.
Your example shows the typical single-beveled edge that is also hardened. These are well made and sturdy jungle knives used for domestic purposes as well as combat. In the second half of the 19th C., the Kachin progressively changed to Shan swords, often with a squared end but also more saber-like blades with pointed tips. In this transition, the Kachin adopted sword had a symmetrically sharpened edge instead of the "chisel"-grind of its more traditional cousin.
Part of the blade seems to have a "hairpin rod" construction such as seen on swords from Tibet and neighboring areas, and again this is not uncommon in swords from NE India/northern Burma. The silver ferrule is consistent with Burmese silver work.
To answer your question about age, I would say this one is probably late 19th or early 20th C, maybe a little older. I would also say the hilt was original to the sword. The black lacquer on the hilt is gum from a particular tree (I don't recall the name) which is very durable and can persist for decades. I have some lacquered pieces that are more than 150 years old and the lacquer is still sturdy and protecting the hilt or scabbard from rotting.
You have a nice example of the traditional Kachin dao Thomas.