Mark with Japanese mark: 唐津住　正國 "Karatsu ju | #433398

唐津住　正國 "Karatsu ju Masakuni". 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 Masakuni, who worked as a "soukenkinkou" in the Nara line of the Ito house. Soukenkinkou is the Japanese name for metalworkers who design accessories for bladed weapons.