Hi all, a learning lurker here with a bit of a puzzle.
I got this tanto a while back, accepting it as a gimei Suishinshi Masahide, though now it's starting to bug me as to the authenticity. After coming across numerous examples of Masahide's varied signatures I am now completely confused... The yasurime and nakago patination is correct. The kanji are written with confidence in the same style, same strokes as many of Masahide's later works- even with the correct stroke direction (if that makes sense?) on the lower left stroke of 秀, which proves the hypothetical forger is attentive to details and studied genuine meis. However there is a lack of kaokuin (which isn't too much of a problem) and the kao itself is so far removed from any genuine kao I was able to find on the internet.
So here's what puzzles me: if the forger was able to replicate the mei to a great likeness then why is the kao so poorly done? If the forger inscribed a wholly believable signature already then why bother adding a kao and increasing the risk of a bad stroke? There is also the question of why the forger didn't copy the mei precisely, with the more common, elongated 心 character (hope you see what I'm describing here) like the other gimeis but rather copied the one which only appeared in some variations of Masahide's signature to make it more convincing?
Then there's the blade itself. I believe it has a ko-itame hada though it is so tightly constructed it is almost muji. I've read that Masahide forged ko-itame, though the examples I've seen were more lively than muji...
Any help would be greatly appreciated, with explanation on your view for learners like me. Hopefully I haven't missed something completely obvious .
nakago- http://s1064.photobucket.com/user/tc9182/media/P1020047%202_zpsrdx17ycw.jpg.html?filters[user]=146475841&filters[recent]=1&sort=1&o=2
overall shape- http://s1064.photobucket.com/user/tc9182/media/P1020049_zpsgfzx8mk4.jpg.html?filters[user]=146475841&filters[recent]=1&sort=1&o=1
blade- http://s1064.photobucket.com/user/tc9182/media/P1020042_zpscstuofzl.jpg.html?filters[user]=146475841&filters[recent]=1&sort=1&o=0