Mark with Japanese mark: 武州住 國廣 "Bushuu ju | #433576

武州住 國廣 "Bushuu ju Kunihiro". 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 Kunihiro, who worked as a "soukenkinkou". Soukenkinkou is the Japanese name for metalworkers who design accessories for bladed weapons.