The term gusoku, or tosei gusoku, describes a complete set of armor of a particular form as used in Japan from the sixteenth to the nineteenth century. This gusoku, a superb example of the armorer's art in Japan, is remarkable for its very high quality and for retaining all of its matching elements in an exceptional state of preservation.

The helmet bowl of eighty-four ridged plates is signed on the inside: Eichizen no kuni Toyohara ju Bamen Tomotsugusaku ("made by Bamen Tomotsugu living in Eichizen province, Toyohara village"). Tomotsugu was the leading armorer of the Bamen School in the eighteenth century. The iridescent black surfaces seen on the torso defense and other parts of the metal fittings were achieved by gindami-nuri (silver powder mixed with lacquer), a material and technique rarely found on armor. The silk lacing on the skirt, in white, orange, green, and the blue, is distinctive; the Museum's example is the only known Japanese armor with this color scheme. The mon (heraldic insignia) in the form of three whirling commas is that of the Okabe, feudal lords of Kishiwada (present-day Kishiwada City, Osaka Prefecture).