Hello Eric,
when it is really old congrats to a very rare find!

It is a Si euli in my humble opinion, one of the rarest and costly Indonesian daggers from Nias. It is good that you have a provenance for it, look that you can get the information when it comes to Europe. Search here a little bit with this name, you will found some threads. Also look to Zonneveld page 123/124.
But please look special this thread:
http://www.vikingsword.com/vb/showth...highlight=euli
It seems that there a lot of copys on the market. Michael will know if it's an original one.
Best regards,
Detlef