Unusual knife for I.D. Asian ?

[colin henshaw]

The blade is sharp for the entire convex side and for that part of the concave side that extends beyond the hilt projection.

Initially I had considered a razor to be the most likely function, but Tim's suggestion that its for basket-making (splitting the fine cane etc), and held in the armpit, makes a lot of sense. Looking on the internet, I see some basket-making knives have curved blades.

Perhaps the idea of a detachable socket for the hilt, was that the socket would remain under the arm to permit easy removal and return of the knife, should it be required for use in the hand as well as in a static position ??