Mark with Japanese mark: 松柏堂　砂川正吉 "Shouhakudou | #433486

松柏堂　砂川正吉 "Shouhakudou Sunagawa Masakichi". This mark comes from a "tsuba", a sword guard designed to protect the hand from contact with the blade and an opposing sword. It was made by Masakichi, who worked as a "soukenkinkou" in the Nara line of the Suangawa house. Soukenkinkou is the Japanese name for metalworkers who design accessories for bladed weapons.