Rivkin

Takada which tries to be sue Bizen but judged Takada because of weird jigane and nioiguchi which is like written down with a pencil, very sharp but a bit artificial. On earlier ones you sometimes see hazy nioiguchi. Its not the best Takada can offer, certainly not the worst. The price is a bit higher than typical resale value at the show of something like that, but not by much.

I looked close at the photos and I think you are right.

There are restaurants and other businesses in Japan which don't serve foreigners or don't speak English and its announced straight out on the door. If you still address them in broken Japanese "but I just want this one thing" they get very angry. Not shipping to the Uk it means no discussion on this point.

Unfortunately unless its some ultra-weird photo issue, such dancing strikes in the signature exclude this being genuine. Regarding to what it dates, its a relatively wide blade with reasonably long nakago... I don't get Muromachi vibe from it, so its probably something later. Financially anything post-Muromachi does not make much sense to polish etc., so I would leave it as is - a Japanese sword blade and a piece of history but not a gold mine.

I always find messages hidden inside sayagaki or setsumei to mark the blade as amazing or evil which only those who can't read between the lines would buy a bit too arcane topic. Good blade is a good blade, interesting blade is an interesting blade. If it was submitted five times, passed around, I am sure competing dealers will make a great story why "IT IS NOT REALLY JUYO LEVEL", but they are able to tell this story about any blade. Or vice versa, with absolute certainty declare that sequence of words in sayagaki does not say what it says, but attributes it to another, unwritten name, five notches higher. I never liked these whispers which echo in every collecting field. 100 years from now there will be so many Juyos most of it will not matter.

Its a wakizashi, I guess 18 inches.

Don't know enough about the signature (Kosho would make it one of the earliest known?? more likely the previous generation), but the work is strong, despite a rather dated polish.

That changes things since near absence of utsuri would shift the date forward. Jifu utsuri - mid Kamakura at the latest... Also near-discards Katayama Ichimonji which I seriously thought about. Could be ko bizen or fukuoka but the slanting is a bit aggressive, hamon is quite wide... Ko Aoe.

Really enjoyed reading it!

On the other hand, jigane almost wants me to say Aoe, and I think there is a very crisp to kaeri as well. Can be Nambokucho Aoe.

Don't know, feels like Osafune Motoshige.

As far as I remember the wording of the original rescript was commenting explicitly that many attend to Tenno (this is late Muromachi, so both Ashikaga and Tenno courts are very modest) with horn kashira which is not even lacquered and therefore demanding that all kashira at court are to bear black lacquer. After sometime having a black lacquered kashira became a symbol of someone who attends at court and the default attire at court, and persisted in such a role long after the original reasoning was forgotten.

I would be inclined to consider the dates around Tensho. Nakago is in good condition, but we don't see too many higaki yasurime in shinto even for mino, the signature is a bit koto with nijimei closer to the mune and a bit more cursive-shallow and its nijimei... Tensho matches sugata - very beefy powerful, no taper, uniform curvature.

Not much to see in images unfortunately. If it is simply signed "Kunitoshi" or "Kunimitsu", such blades do paper with a note Muromachi. However Rai addition basically makes it impossible to assign it to "Muromachi Rai" since such thing did not exist. There is Rai Chiyozuru but it did not use Rai signatures and is rather different then this blade. Mino Zenjo or Ryokai, later generations, are a possibility. There is some masame and otherwise jigane is not a good match for kai Mihara, so maybe. But its all a speculation.

Two very rare Edo period smiths make for a really attractive signature and its unlikely to be faked. However, quite possibly it is otherwise just average Ishido(?) sword, attractive but not more than that. If its not, that would be an exception rather than a rule.