all of this looks true, LGM.
I am NOT an expert by any stretch, but I will provide you with the limited insight that I have, worth everything you paid for it. And I'd also like to add that I am NOT an expert. By reading this you are indulging a layman who enjoys a good challenge and learning opportunity to be schooled by the more-adept. Did I mention I'm not an expert? OK here's my NON expert observations...
Without a Mei or ko-Mei it can be literally impossible to know the school or smith. What's more, the kanji on the blade do not look like any language I've ever seen, and not japanese. I COULD BE WRONG, but I don't recognize the kanji at all. Decorative?
Interestingly I can't believe how any high carbon steel blade would survive in that good of shape over a 30 year period of time without a patina, rust, or other types of deterioration. There are obvious flaws in the metal, but for what isn't blackened, there's no visible deterioration issues. What kind of care has it received?
I'm amazed at the numerous tiny nicks on the ha, especially in the kissaki and monouchi. Either time has taken its toll, or that sword saw quite a bit of cutting on its edge, particularly by someone who knew what part of the weapon to use for cutting--because the bu-ha has not been nicked. The former theory is probably more true, though.
I agree with LGM that some things look very strange. Tsukamaki has some kind of faux samegawa with what looks like nail holes in linen? The kashira affixed by some method other than the ito, and it's so large, featuring a metal hook/handle/loop? The loop is not unheard of (I've seen it in some historical photos of swords), but it was a cloth loop and the kashira was still not nearly so large in proportion.
The sharp taper on the tsuka is odd, but reminiscent of some of the ancient katana in the 1800's (see
quanonline.com/military/military ... ord_45.php ). It is quite short in proportion to the blade. It does follow traditional construction customs of fuchi+seppa+tsuba+seppa+habaki. However that's the smallest tsuba I've ever seen in any sword. The fuchi is mashed in, hinting at underlying problems or shaping of the tsuba. The upper seppa and habaki are ill-fitted, maybe the result of your attempts to remove the tsuka, or some good old fashioned banging? The ha area right above the habaki (sometimes called the bu-ha) looks like it's been polished intensely, probably to remove a chip in the blade. Either that or it was forged very strangely when compared with traditional or even modern geometries.
Then as for the blade, I'm not an expert on historical sword making, but the shinogi is lower on the nagasa than what I'm used to seeing. Furthermore, it seems to wander up and down vertically for the whole length of the blade. I'm sorry, but that is quite bad geometry. The shinogi should run parallel to the mune without deviation.
Additionally, towards the end it's almost as if there is a ghost yokote about a quarter inch into the actual boshi area. Also, the ko-shinogi should flow upward to the tip in an arc, not a straight line. If the bit about the yokote is true, that is "bad" kissaki geometry, and specialists are particularly picky about the kissaki.
Do you have pictures of the full blade? The sori looks uneven as well--particularly toward the kissaki.
The leather saya seems out of place in a tradition of sword making that used ray skin leather. Ray skin was expensive, so it could be that the owner opted for something less costly. Scabbards native to India tend to be leather-wrapped and feature an endpoint flourish decoration, such as the one you see on yours. Do you have a photo of the koiguchi? That could be telling.
Full disclosure: I am not an expert. There you go, my NOT expert observations on the sword.