Another mandau Qs

[Green]

Thank you all for the explanation and I do agree about the blade which is flat on both sides and not the typical convex/concave blade of the classic mandaus which I also have in my small collection.

On related topic I have another flat blade which is pitted around may be 0.3 cm across in several places. I'm wondering if this is simply bad blade or purposely added for whatever reasons. any explanation ? I tend to believe that it's just simply a bad blade.