Rivkin

Not much could be said, but I like the signature, the blade is most likely circa 1540, but the sugata is very general and it could be substantially earlier - in theory, but usually less so in practice. Probably under 2 inches suriage.

Its difficult to make such analysis, because coins were devalued, prices fluctuated, 1710-1790 no one was buying any swords, koku stipends experienced both inflation and deflation, but I don't think two ryo stipend is something that was actually meant in the text. Generally a very good stipend was 150 koku. Top administrator for a top clan could make 500. The least stipend was often in 25-40 koku range, and in clans like Uesugi you were expected to have a side trade at this level. Hatamoto were more or less equivalent to a lesser clan serving a major Daimyo, so they are not one to one comparable to samurai. The main question was how much spare cash existed after expenditures, especially since the system typically aimed for "zero" as the answer. The system was also "Pareto" designed, with sharp boundaries between the classes without "in between" steps like 120 or 225 koku. Honami valuations are more or less fantastic rather than market based. Very few clans which could more or less consistently acquire swords at high level. Probably most exchanges involving such swords were not purchases, but gifts. In which case Honami valuation suggests the gift's value... Very good modern sword would more often than not be under 10 Ryo, quite affordable for the upper administration. Then again the real market prices (i.e. pawn shops) constantly fluctuated and what would be taken as collateral at 100 Ryo in 1700 and in 1740 would be very-very different amount of material.

Its a bit like buying something inside a big black bag, but I would say yes even at 800 there is some potential. At 500 the chances of this being a bad deal are not too significant. I personally would be interested in looking at better pictures if you buy them...

Anything stellar? More likely not rather than yes. But I would also consider second from the left. It has a certain cool factor to it.

Does look like the early shinto Kanemoto.

Not being a tosogu specialist, but to me FK looks more like late Hamano Nara rather than Mito per se. Would love to have the first tsuba though....

Deep, well spaced yasurime can be shinshinto. Boshi is not seen, its another thing to check. Ofcoarse its possible to try to guess the signature.

I'll hedge not being a tsuba guy, but the first two look like late pieces (clean thick profile, very flat surface without much forging or variation), cut and then artificially aged and purposefully chiseled in a rather rough manner. Datewise... Late Edo to Meiji? Probably.

They are not junk. First row are well known old designs, but the execution even in such pictures feels late. XIXth century? Needs to be studied though. The one in the center to me might be the oldiest. The next on the right I would say both particularly late and sloppy. Overall its real tsubas from not the most expensive pile...

MFA blades look much better in oshigata than in real life. Unfortunately it is a disappointment.

Both, though Sukesada does look like a good blade just not something commonly making Juyo. Kiyomitsu feels more like a typical quality work of the smith rather than his best of the best.

Having very little idea what guarantees Juyo... passing this one would be a bit of a surprise.

A lower grade hamamono with exaggerated expressions and very simplistic execution in most places, except essentially for one figure. I don't think its modern (not being tsuba specialist) because such uneven execution is very typical for lesser hamamono.

Probably Kaga (nakago, suguha) and I would guess later Muromachi one.

By the way a very good example: https://www.facebook.com/permalink.php?story_fbid=pfbid0DuWnGr4pt2ChaYLf78neA1GxvTSRSijfmk8X9AxF8ZvWstPJS5DRM6k3U4em7Cipl&id=100064812335888 Classic late groupings, but top mainline Sukesada work predictably shows much stronger nie. Midare utsuri though very seldom encountered past 1500. It still feels in regards to the mumei blade shown the very well defined, uniform groupings might be suggestive of later than Oei attribution. I don't think its as late as Sukesada or Kiyomitsu, but it might be post Oei generation.