Chinese folklore gives association of Shen - clam monster as a dragon or sea monster than can change shape and create mirages. Many times being associated with death. A box containing Shen can easily symbolize that death has past and kept inside this box for protection. Cloisonné has been around for thousands of years, used worldwide and is an expensive process to complete correctly. Cloisonnes or wires separate the various colors which need to be fired in a kiln at separate temperatures to harden. Perfecting this technique has taken lifetimes. A large clam-shell box as this example would be had by a wealthy patron, probably protecting themselves from a recent death. Approximately 5 5/8" Wide x 3" High x 4 1/2" Deep. Ming/Qing.
For An Early Example Of This Shape In Chinese Art:
Christie's New York: March 24th, 2022 - Important Chinese Ceramics and Works of Art: Lot # 750:
AN UNUSUAL SMALL CLAM-SHELL BOX AND SILVER COVER
LATE TANG-LIAO DYNASTY, 9TH-12TH CENTURY
The cover is finely decorated with a bird in flight grasping a flower in its beak, and surrounded by further flower branches, all against a ring-punched ground. The silver cover is attached to the clam shell by a linked metal chain.
2 in. (5 cm.) wide, cloth box