Japanese traditionally made family heirloom wakizashi.
I was informed this was a Koto blade and forged in the early 1600s. Used as a naval officer's sword and, potentially, as a pilot's sword in WW2.
The blade measures 21.5 inches. Bares a naval sharkskin saya. But retains its original Samurai mountings (potentially re-wrapped ito?) The tsuba. I think may be Tosho and predate the sword. The tsuba is meticulously hand carved (jumping lion and rose bush?). And has nanako surfacing on both side. There is also what looks like gold foil inlay in the handle (resembling a catfish and clouds). Which has partially flaked off. The blade also has a 2 piece 2 tone copper habaki. There is also evidence of what may be a defensive blade strike in the defensive zone (lower quadrant) of the blade. Potentiallly has kitikomi im in one spot on the spine (Photos at the end). Along with very small scratches in one area on either side of the front side of the blade. Upon very close examination. I have found a few other small indentations in the blade edge. Which may have been polished out. The blade is sharpened to the habaki.
The Hada I would describe as "Itame with areas that resemble "O-Mokume". The "Suguha" hamon exihibits thick "Masame"hada with specks of nie. Along with streaks of nie and noi. With a bit of a reflection of itself hovering above the main temper line. Which consists of a darker band of, is it martensite? Followed by a thin sparkly band of Nie.
The blade is supposedly signed by the 1st generation Tadayoshi. It reads 肥前國住忠吉作 ("Hizen no Kuni Ju Tadayoshi Saku"). But I believe it was most likely signed by an approved student. I do see inconsistencies in the mei. The kanji for Hizen is written with the dash mark inside, not out to the right. But interestingly. It is a horizontaI dash as the Tadayoshi school wrote. Not a slightly angled vertical dash as Hizen is properly written. Maybe placement had to do with the area the smith had to work with? I have read that swordsmiths at large schools would have approved students make blades for them. But it could just be completely gimei. There appears to be remnants of some sort of inlay in the mei. But the bare steel underneath, which can be observed in the mei, is the proper color and oxidization as the rest of the tang. So I assume it was done at or around the time of its forging
I was also informed the blade is more Bizen NOT Hizen. But I have also read that the Tadayoshi school did produce some Bizen replica blades early on.
My questions are. What do you think of my analysis? Quality of the blade, hamon, hada? What period do you believe it is from, along with the tsuba? And what are your thoughts on many of these gimie Tadayoshi signatures actually being from students or close relations of the school approved to make swords? Could this sword have been mumei that was recognised as Tadayoshi and signed then? The blade and mounts speak for themselves. I believe it lends towards the blade being of fine quality. Or at least who mounted it thought so.
Notes: Included photos of every inch of the blade. Up close areas of interest in the hada and hamon. The signature, polisher's marks and potential signs of use. This is my 2nd sword and 1st traditionally made blade. I am still learning the ins and outs. I am not upset for it to be gimie. The blade itself and mounts are fantastic. I am just looking for people to discuss it with and give me their thoughts.
Thanks for your time.