MauroP

That's my library, but the books in it were acquired quite randomly... https://www.dropbox.com/s/1o3db7r4le9hytq/Japan %26 nihonto-related library.pdf?dl=0

"Tsuba - Kodogu Gadai Jiten" is possibly the best reference book for subjects from Japanese artistic tradition in tōsōgu, and quite easy to find. Unfortunately it's written in Japanese. I tryed to compile an index. See here: https://www.militaria.co.za/nmb/topic/31049-tsuba-kodogu-gadai-jiten/#comment-317709

Hi Mark, I think the tsuba doesn't look so bad, it could even be a ko-kinkō piece, though unmatched to a saya with kogatana slot.

Another example of Heianjō-zōgan tsuba with shakudō gan-kin.

Aizu-Shōami or Mito?

@Thomas Sinclair In my database I've recorded 7 tachi-kanagushi tsuba; 3 out 7 can be oriented according to their decoration, and all are edge up (as in katana mounting). In 5 tsuba attributed to tachishi (is the same as tachi-kanagushi or not?) the only one that can be surely oriented is also edge up. So what's the meaning of such attributions is still unclear for me...

Here below some examples of vertical nanako tsuba. No.1 papered as tachi-kanagushi, the others as ko-kinkō. No.2 has a sanmai construction. Unfortunately no ko-Mino example to show.

The kanji read Otsuryūken Miboku Hamano. More than one artist signed that way.

Here a tsuba (縄暖簾図透 - nawanoren no zu sukashi) attributed by NBTHK to Inshū Suruga school.

Pretty sure that most sanmai tsuba were not produced with repoussé technique. Here below an example of an unusual large tsuba whose shakudō plates show lack of decoration pattern near the border. That's a proof that the plates were produced in standard dimension and then adapted to the "core" plate. Nontheless that kind of tsuba should be old enough to deserve a ko-kinkō attribution.

About No. 217: the tsuba below is described as shi-hō warabide sukashi (四方蕨手透 - openwork of fern sprouts in four directions)

Ben fatto Luca! I just had a look and found it a very promising paper; surely I'm going to read it thoroughly.

The kin'in (the golden seal is not exactly a kaō) is consistent with Seiryuken Eiju.

In my records I count 6 mumei tsuba with Hikone attribution and just one reported as Sōten (and 7 more signed Sōten). So, if unsigned, the tsuba usually takes a paper with Hikone written in it.