this blade section is similar to the Japanese "unokubi zukuri" blade, though "chisel" bevelled, of course. I suspect this is a perhaps 1930s or later piece (?) but the swedged spine certainly different than the ones I think are distincly 20th(?) where a more subtle (and properly) high shinogi effect is acheived by the whole blade being thicker at the front edge, and then bevelled. Here it is only for part of the length (and much more extreme, as we've also seen on Mandaya swords, coming to a rebated edge, I should think), with the rest (the non-cutting base of the blade) having a different cross section, here only on the ricassoe/shaft, with the bevel starting with the blade per se (are you following me on the shaft-and-blade concept? I'm fascinated with it, so get used to it, I guess....
), though I've seen a similar thing done at the tip of visayan swords with a straght cutting blade that turns into a curved hook-like tip. These seem to me of the newer style, high-shinogi, and the shaft-and-blade concept seems to have been abandoned for the (European?) concept of ricassoe as part of the blade?
Is this clear at all? Let me "save" it and then check