THERE WAS A POST ON THESE QUITE A WHILE BACK THEY MAY HAVE BEEN REFERRED TO AS SCARIFICATION KNIVES. IF I REMEMBER CORRECTLY THEY WERE FROM AFRICA AND THERE ARE SEVERAL VARIATIONS IN BLADE SHAPE. THE DECORATION ON YOUR EXAMPLE IS VERY NICE. PERHAPS A SEARCH UNDER SCARIFICATION KNIVES MAY TURN UP THE TOPIC. GOOD LUCK