This guardless dagger (‘aiguchi’) is probably the work of a smith named Masatsugu who was working in Japan during the period 1830-1844. In this case the dagger and mounting are contemporary. It is, however, possible that the blade was made in the mid 15th century by another smith of that name. A design of a plum branch and bamboo stem has been carved on the surface of the blade itself. If the blade was indeed made before the 19th century, the carving would probably have been done when the blade was mounted in the early to mid 19th century. The form of mounting and decoration is very much in the taste of the period 1800-1850 and the dagger was most likely mounted for a rich merchant.

The wooden scabbard is decorated on one side with reddish brown lacquer in imitation of a tree trunk, its branches extending to the other side of the scabbard, which is decorated in glossy black lacquer sprinkled sparsely with gold flakes. The metal mounts are of silver, gold and patinated copper. The ring for securing the dagger is in the form of a kettle.