SteveM

Works for me.

This is the swordsmith's signature 濃州関住村山国次 written in a highly stylized way. Nōshū Seki-jū Murayama Kunitsugu. It means "MURAYAMA Kunitsugu of Seki city in Nōshū province made this". Nōshū province is present-day Gifu prefecture. It was made circa 1938-1945. The writing is quite difficult to decipher. Take a look at the attached thread which shows a sword with the same signature.

Just booked my room. Count me in for Friday dinner if there is still room.

Looks nice. The online seller misspelled the artist's professional name, and in the text inside the pictures, the seller misspelled both the artist's real name and the artist's professional name. It a really sloppy, lazy listing from this seller. I see another tsuba by the same artist from this same seller with a similar misspelling (link at the bottom of this post). It's a level of sloppiness or laziness that makes me slightly suspicious. Anyway, the theme on this tsuba is (obviously) bamboo and plum blossoms. It is a winter theme, and on the box they refer to these two symbols as the "two elegants" (ニ雅) which is a poetic allusion to plum and bamboo. No idea if the mei is authentic or not. https://page.auction.../auction/m1120190916

Professional name of Isshu (一舟).

The box says 集雅堂 (Shūgadō). It's the name of an antique shop in Tokyo Osaka. It might also be the name of an artist, but the antique shop tends to clog the search engine results.

Wow - Tony what's on the other side of that tsuba?

潮見町一組 Shiomi-chō, ichi-kumi It's the name of a location (Shiomi-chō, possibly in Saitama Chiba prefecture) and "ichi-kumi" means "group #1". Maybe a neighborhood association, or the name of an organization that might have been in charge of collecting swords.

Tough to figure out Right side looks like 厳藩 ? Place name? Left side looks like 囗行 ? At first glance it looked like 正行, but when I expand the picture it doesn't seem to be 正.

Hmm. Now I'm doubting myself. But has the "nobu" been completely (expertly) erased? Why erase the nobu and leave the star stamp?

Kikumitsu, but it's very confusingly inscribed into the tang.

Hello Ben, your reading/translation is correct. I think there are probably many more smiths than the two you found, who signed with Bishū Osafune-jū Sukesada. Given the shape and the signature style, I wouldn't be looking any farther than the late 1500s for this sword's origins. It doesn't show any signs of being drastically shortened, so we can assume it was made as a wakizashi (as opposed to a tachi or katana, which was later shortened). The extra hole in the nakago looks like it might have been made to accommodate a new tsuka, which is pretty common. The signature looks fairly crisp and clear. There isn't too much patina/rust build-up on the tang. So maybe 1600s to 1700s. The kogai is signed 後藤光信 (Gotō Mitsunobu), with monogram. It's kind of a blurry image, so I can't really see the design on the kogai, but it's probably best to think of this signature as a forgery. Gotō Mitsunobu was a famous metalsmith, working in the early Edo era. Looks like the utility knife (kogatana) has a signature that starts off with maybe 千代 or 十代 (Sendai- or Jūdai-). Can you take the knife out of the kozuka? They are made so that the knife can be readily replaced, and usually they will come out without exerting much force, but if it won't budge then leave it as is. Names on kogatana are often an "homage" to a famous smith, rather than the name of the smith who made the kogatana.

The tag has the name and address of the former owner. It is from a small town on an island off the coast of Okinawa. 勝連村字津堅 與那下武不囗 Katsuren-mura (name of village), Tsuken (name of island/neighborhood)) The owner's family name is Yonashita. (Can't read the given name) It's a very rare name. There are still descendants of this person living on that island. https://maps.app.goo.gl/TX4HfuL4vyvjPxp19

Note that holly is hiiragi (ひいらぎ - two "i" sounds together creating an elongated "i"). Unlikely to be any wordplay here, I think. Maybe they are symbolic of bits of family crests. Just a wild guess.

That's it, Piers! Thanks much for that.

Looks like a Brian Tschernaga two-tone double-piece habaki. Inner piece is shakudō and outer piece is gold foil? (possibly solid gold, but quite expensive to make a solid gold outer piece nowadays. I know he makes such pieces.

地刃㞮耒宜敷 Jiba deki yoroshiku well made Jiba ("well-executed" works for me also) I don't know what that final squiggle at the end of that line is. Some mark indicating the end of the sentence? Tanobe-sensei does like to throw in obscure things into his inscriptions.

kiki kiku

The writing on it seems to be fake.

They come in 5 sizes. All sizes are available in all colors. (Posting a pic from Amazon Japan).

I also think this part of Markus's post is very important; Regarding the inscription: I've never heard of there being any connection between certain inscriptions and customers for the sword (excluding the obvious "dedication" inscriptions). Anyway, looking forward to seeing the photos.

According to Guido's list, Yoshitoyo was active in Ansei (1855-1860).

No date for the cutting test. The paper says the sword itself is circa Tenmei (1781-1789)

My guess 夕　工人　（花押）　彫鐫 Made by Yū, Carved by (kao)? One guy made the habaki, the other guy put the artwork on it. Said with 50/50 confidence.

There is a lot of good information here (maybe you've aready seen); https://markussesko.com/2015/08/11/the-wakizashi/#:~:text=The honzashi of the samurai,measurements were slightly adjusted later. With so many changes in the laws regarding sword length, one can assume that they weren't being followed or enforced very strictly. Also, the definition of "shaku" wasn't standardized throughout Japan until later in the Edo period. Basically there were different versions of "shaku" in use depending on the location (and profession...fabric makers have their own shaku). There are a couple of threads on this topic here on NMB, which I think you may have also seen. https://www.militaria.co.za/nmb/topic/6650-swords-and-length/page/2/ Here is another one https://www.militaria.co.za/nmb/topic/44442-evolution-of-the-shaku-unit-of-measurement/ 59 cms makes a pretty long and impractical companion sword. Yours could be a sword meant for someone not of the samurai class. Has it been shortened (at the machi) at all? As is usually the case, without the provenance, you will never be able to say with certainty who owned the sword or what their status was.