Ko Katchushi Tsuba. This looks to be an old iron tusba, maybe from the Muromachi or Momoyama period at the latest. There is rich tsuchime in the hi and small tekkotsu in the mimi. These are usual traits of Muromachi and Momoyama period Katchushi and Tosho work. In regards to the theme, I believe this represents Moonshine but could also be a crane with the two wings arked around the seppa dai. I like to feel however it is a large bright moon in the night sky with a single star underneath. It may also represent family crest, Tsunagiduki (繋ぎ月).

It is possible that this sukashi was a later addition, and possibly added in the Edo period. If this is the case, then I suspect it was originally a Tosho tsuba. The NTHK papered this tsuba as Shoami, based on this theory, even though they agree it is an old plate. I believe however, regardless of what was done by whom, it is still a Katchushi tsuba.

One could argue that if the theme was the crest of the Tsunagiduki, then perhaps the sukashi was ordered to be added by a smaurai of this family so as to be proudly displayed when the katana was worn.

The dimensions are X x X and X thick.