The purple-tinged blue glass bowl is made by mold-blowing. The side has a four-layered tortoiseshell design. In the top layer, twenty-five concave tortoiseshell patterns are cut around the body. The foot contains a line-engraved inscription "Made in the reign of Emperor Ch'ienlung of the Ch'ing Dynasty." Glass-making in China reached its zenith during the reign of Emperor Ch'ienlung. The cut pattern of this bowl has some elements in common with the transparent tortoiseshell patterned cut-glass bowl preserved in the Shoso-in. The eastward expansion of Persia in the Sassanian Dynasty seems still in evidence in the reign of Emperor Ch'ienlung.