Identification please...its a odd beauty!

[Henk]

Michael,

It is no conclusion but a guess.
It looks like the tang is square but it is hard to see on the pics. Also the position of the tang is not like the Piso swords you're showing.

But I was looking arround in some books and found in the book by Van Zonneveld the description of the Kalasan.

Looking a bit further Van Zonneveld shows some drawings of javanese sabres with pamor. So it might be such a javanese sabre. These blades could also be brought from Java to Sumatra, something that was not uncommon.

Being a javanese sabre it would explain the mendak like ring. In my opinion it isn't a keris mendak. The shape of the hilt? I dont know.

The weapon is a bring back item from the dutch colonial period. Maybe javanese or an assembled piece from Sumatra and not a Batak weapon at all. But your guess isn't so odd either.

I haven't either, so far, seen any Batak swords with Arabic texts on them.
But some of the tribes have converted to Islam and my experience is with the older variations of Batak weaponry so...

Maybe someone else can give his opinion?