Ciao Luca, nice tsuba indeed. The surface of iron plate is quite corroded, so maybe it could have been migaki-ji in origin, and the inlays, now protruding a little, were intended as hira-zōgan. The slanted grooves on the circumference configure a nawame-mimi (縄目耳). The two strokes in the mei looks too much clear-cut, and possibly were carved much later than the time the tsuba was made.