A signed Japanese tantō bearing the inscription “Bishū Osafune Sukesada” (備州長船祐定) together with a date from the Tenshō era, measuring approximately 22.5 cm in blade length with no appreciable curvature.
The blade displays a distinctly late-Muromachi character, with a clearly visible and naturally formed itame jihada and a broad, dynamic midare-based hamon with pronounced undulation. The relatively substantial form, visible forging grain, and active tempering are characteristic of the Sue-Bizen tradition of the late Muromachi period.
The name Sukesada was used by several generations of swordsmiths of the Osafune school, and the dated inscription places this work in the Tenshō era (1573–1592). The combination of the surviving mei, date, sugata, jihada, and hamon makes this a particularly representative example of late-Muromachi Bizen workmanship.