Half Pi Disk

Half Pi Disk
Ch'i-chia Culture Style (ca. 2200-1800 B.C.)
Diameter: 39.7 cm,
diameter of hole: 6.8 cm, thickness: 1.6 cm

??The greenish jade of this piece exhibits striations and banding, and the surface has turned brownish-red. This round semi-circular piece has an area along the upper rim that is damaged, and each side bears a straight line that indicates where it was cut. The hole was drilled from one side, but it is not exactly in half. This suggests either that the hole was not drilled in the middle of the original pi disk or that this piece was intended as a half disk.

??On one side is the engraved poem of the Ch'ien-lung Emperor (r. 1736-1795), and on both sides are four-character engraved inscriptions of the emperor.

Traditional studies on huang pieces in "Illustrated Study of Ancient Jades"

...mention that "large huang" were half pi disks used to venerate the deity of the north. Most of them were worn as pendants on the chest and thus known as "pendant huang".