Jacques

eBay.... I never bought a sword without having it in hands....

An exemple to share ? Kasane is always mesured to the mune.

Yamato den = high shinogi

Obiously gimei https://www.samuraimuseum.jp/shop/product/antique-Japanese-sword-wakizashi-signed-by-mino-no-kami-jyumyo-nbthk-hozon-certificate/?srsltid=AfmBOooramjpL2uGeOLrUD0P28RwlYDsa4aUalfgD_SBsxJpnjvUi4dq

https://www.seiyudo.com/ka-020523.htm

NIdai Nobutaka

From Markus index of Japanese swordsmiths (Nihonto meikan translation) Kaneiwa (兼岩), Bunmei (文明, 1469-1487), Mino – „Kaneiwa“ (兼岩), „Nōshū Seki-jūnin Kaneiwa“ (濃州関住人兼岩) Kaneiwa (兼岩), Eishō (永正, 1504-1521), Mino – „Kaneiwa“ (兼岩), „Nōshū Seki-jūnin Kaneiwa“ (濃州関住人兼岩) Kaneiwa (兼岩), Eiroku (永禄, 1558-1570), Mino – „Kaneiwa“ (兼岩), „Nōshū Seki-jūnin Kaneiwa“ (濃州関住人兼岩), gunome-midare in nioi-deki or nie-loaden ō-gunome-midare to hitatsura Kaneiwa (兼岩), Tenshō (天正, 1573-1592), Mino/Kaga – „Kaneiwa“ (兼岩), „Nōshū Seki-jūnin Kaneiwa“ (濃州関住人兼岩), this Kaneiwa moved later in his career to Kaga province Kaneiwa (兼岩), Genroku (元禄, 1688-1704), Mino – „Kaneiwa“ (兼岩), „Nōshū Seki-jūnin Kaneiwa“ (濃州関住人兼岩)

According the Nihonto meikan Nagatsuna never signed Awataguchi Nagatsuna 粟田口長綱, I would think it's gimei..

Worth reading https://www.nittetsukou.co.jp/eng/karematuzawa/2.html

Slightly erroneous: sand iron is not suitable for blast furnaces, so ore must be imported. The tatara will continue to operate alongside the blast furnaces.

It's not just the hada that characterizes a smith or a school. Having said that, without having the blade in hand, I can't say anything - the photos don't show much.

The major difference between koto and Shinto is the way steel is made. In Koto, it's the swordsmiths who make it, but this is no longer the case in Shinto, which means that the steel loses the specific characteristics of each region and becomes uniform.

The third stroke on the left of the kanji Kuni is reversed, that indicates a work of the nidai.

If you are not in a very wet environment you can avoid oil. It's that i do for decades.

Kanji Kuni clearly says that it's the nidai.