Shitsukohei is a Japanese lacquer ewer, which is kept at the Shosoin treasure-house, Nara, and is said to have a capacity of three sho and a half in the Nara Period. The authors calculated the volume of the Shitsukohei from its x-ray radiograph and crosssectional views; they also actually measured its volume by filling it with water, millet seeds, and silica beads, separately. From the results obtained, they concluded that the real volume of Shitsukohei is within the range from 2,639 to 2,883 milliliters and that, therefore, dai-sho, being one sho in the Nara Period, equals to a volume in the range from 4.18 to 4.57 go in the present volume scale.