Mark with Japanese mark: 佐州住　利貞 "Sashuu ju | #433497

佐州住　利貞 "Sashuu ju Toshisada". 佐州住　利姓 "Sashuu ju Toshiuji". 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 Toshisada, who worked as a "soukenkinkou" in the Nara line of the Sawatari house. Soukenkinkou is the Japanese name for metalworkers who design accessories for bladed weapons.