Iron tsuba of round form with design of triple diamond (matsukawa-bishi) in openwork (sukashi). Square rim. Ko-Tosho school. Nanbokucho period: Late 14th century (Oan/Eiwa era). Height: 92.3 mm. Width: 92.3 mm. Rim thickness: 2.5 mm. Center thickness: 3.0 mm. Provenance: Sasano Masayuki Collection, № 15: "Two small lozenges are attached to each end of a larger lozenge. Most Ko-tosho tsuba have inspirational designs, however this has a rather casual appearance, although it represents the unstable political situation at the time".