SteveM

Name on the sword is 包囗　(kane-something). The writing on the scabbard looks like a buddhist incantation, but nothing pops up when I do an internet search. Pictures of the full sword itself are usually better than close-ups of the tang area.

第一船司廣島支部 First Shipping Command, Hiroshima Branch

I think you are referencing a different Shigetsugu. The one you mention above is 茂継. Or another who did in 1966 is 繁継. The one on your sword is 茂次. All are pronounced Shigetsugu, but they are different people.

Looks like 茂次 (Shigetsugu) using an alternative form of 茂. I could be wrong. Markus Sesko lists only one smith named Shigetsugu, and from the looks of your sword the smith is different from the one Markus lists. Could also be a fake signature.

I think you've got it!

The letters on the tsuba are part of the design, rather than a mei. 七十二才雪舟筆 Nanajūni-sai Sesshū hitsu Sesshu drew this at age 72. It is (presumably) an homage to the ink painter Sesshū. The letters inside the cartouche also say "Sesshū", in seal script The mei inside the gold cartouche on the top tsuba is 囗乗 (something -jō) I'd look through a list of the Gotō artists that used the kanji character 乗 to see if any look promising. I think we can rule out 宗、栄、壱、謙、廉、覚、顕、程. These are the obvious ones...

備州長船勝光　Bishū Osafune Katsumitsu Compare with this one here https://www.touken-world.jp/search/22548/

Looks like a funky sōsho rendition of 寿

Yes, usually the cutter's name is part of the saidan-mei, but not on this one, unless I've misread a name as something else. There are two bits that I didn't quite understand (為出生、以首) but they don't look like names. Still, it looks like a legitimate dedication to me. 1867 would have been at the very tail end of the cutting tests. Could be the tester didn't want any attention drawn to himself. Or, it could be the people presenting it to Mr. Minamiyama didn't want to upstage him, and wanted only his name on it. But those are just wild guesses.

小本太夫　Komoto Dayū (other readings possible). Could be a real name, could be a fake name. I don't think you'll find any swordsmiths with this name, so its almost assuredly not a mei. Maybe some random person who wrote his name on his sword. Could be a name someone scribbled on to the sword to make it look somehow authentic. Looks a bit deliberate to be scratched by some random guy, but who knows. (Dayū would be a strange name for a guy, so it probably has a different reading).

法久作　Norihisa-saku Norihisa is a modern swordsmith.

杉田善昭作　Sugita Yoshiaki-saku Modern swordsmith, who passed away about 6 years ago. Well-known. Is there a date on the other side? No guarantee the signature is authentic.

The Wakayama entry form Shunmin (春民) says: Surname of Funakoshi, who later adopted the name Shunmin (春珉). Extant works with the mei of Shunmin (春民). Born in May of Meiji 1 (1868). Died in Showa 15 (1940) at the age of 73. He had two apprentices; Shunkai (春海) and Shunshu (春秀). So according to Wakayama he is a post-Edo artist, who only used the name Shunmin, albeit with two slightly different variations on the second kanji (民, 珉), both of which are pronounced "min". Beautiful tsuba. Makes me want to see more works from him.

備州長船盛光 Bishū Osafune Morimitsu, is what the signature says. There is no guarantee of its authenticity. Always better to look at the sword, rather than focus on the signature.

兼氏　Kaneuji