Indonesian terms for these two

[kai]

Hello Séverin,

I also have a weapon from the same family but I never knew the name
In the Detlef link I saw things looking similar but still quite different for the blade.

What part of the blade is sharpened in your example - only the larger concave area?

It looks pretty much like a billhook and similar blades are widely utilized as tools. It will be tough to link this to a specific origin, I guess...

Regards,
Kai