SteveM

Yes, I saw that one, too, and was equally intrigued by it. What a coincidence to have two copper tsunagi show up in just a couple of weeks. I would think copper would be an unlikely choice for tsunagi material, because it's going to corrode and play havoc with the insides of the saya. Maybe its alloyed version doesn't corrode so easily. By the way, I liked and agreed with the translation that @xiayang gave. There is an additional aspect of it that may be relevant. The Japanized version of the saying on that sword, "一心定めて、万物服す" was a slogan of Former Prime Minister Nobusuke Kishi (1957-1960), meaning basically "If one acts with intention, one can conquer anything". No doubt he borrowed it from the Zhuangzi.

No, I think the craftsman who made this would have received these two characters from his mentors. Perhaps the ame character comes from a mentor in the copper crafts. I say this because the kao at the end of the name tells me that this person used this name/signature on other works in his career, so it probably wasn't specific to this item. Just wildly speculating; maybe the person who made this was once a swordsmith, but gave it up due to the decline in sword production, and moved into copper crafts.

雪斎書 = Sessaisho (presumably the art name of the person who made the tsunagi) 宗雨 = Muneame I would imagine this is the professional name of the maker. I haven't seen a copper tsunagi before. It would be an unusual extravagance. The name is also kind of unusual. Mune is common, but 雨 (ame) isn't a character you would typically expect to see in a name.

I don't think this is a division within Okada. Just a general stamp indicating (or advertising?) that Okada performed the adjustments.

窮則独善其身達則兼濟天下 Something like: In times of plenty, the virtuous man strives to help others. In times of need, the virtuous man strives to help/improve himself.

Yes - that's 義 gi/yoshi

The post that I linked to contains some more information, but there was a smith named Yanagawa Shōshin (or Seishin, both pronunciations are possible, and I haven't dug deep enough to figure out which one is correct, or if there is a consensus). There was speculation that the smith later added 右 to his name, thus the new name became 右正心 (Ushōshin, or Useishin). There have been a few swords with this signature on them posted to NMB. Not a great deal of info on this smith, so its all a bit murky.

正心作 = Shōshin-saku Could be this guy. Needs a closer look to tell for sure.

I think they are both 文政, its just that the top picture uses a variation (𭐠) So 文政ニ卯年 and 文政元寅年

Just to clarify the pronunciation of each kanji 源　Minamoto 清　Kiyo 麿　marō

光長 Mitsunaga

The valuation is in the first photo: 代千三百貫　1300 kan.

Yes, George has the correct date. The signature and kao are Hon'ami Kōson. The other side is a valuation.

This one is signed Gotō Hōgen (aka Gotō Ichijo), made at 78 years of age. This would place the date of manufacture around 1868-1869.