This is a mokume ji tsuba in the design of a lock. It was made by Nakahara Uji Toshisada and is signed. The mei reads, "Sashu ju Toshisada". Toshisada was the founder of the Sado school. There were two generations. The shodai was most active around Tenmei (1781-1789) and the nidai was active around Kansei (1789-1801). The workmanship of this tsuba is delightful. The mokume ji is clear and strong, showing the grain even in the upper and lower sections of the lock. The design is well executed and the tsuba is in an ideal state of preservation. This comes with an NBTHK Hozon paper and a deluxe paulownia wood storage box.