Unusual Etch on a Moro Blade

[delor]

When a blacksmith didn't want to use rare good steel for the whole blade, he had to choose between two kind of construction :
- sandwich : 3 welded layers, with central good steel layer (first photo)
- welded edges : 3 welded bars, with good steel at the edges only (second photo)

Sandwich is much stronger because the welded surfaces are wider. Weld lines are quite irregular because of the strong hammering for the welding of the whole surface. I believe this is the construction of your blade.
(Welded edges are easy to detect because they show very regular and straight weld line because of the light hammering).

Of course, each of the separate parts can either be homogeneous or composite material (laminated & twisted core being the most traditional structures).