Wucai colour is laid on finished white porcelain and fixed in a low-temperature kiln. The red carries iron and the green copper; after three hundred years the parts that were touched fade first, so the order of loss across the dish can tell you whether it was used or kept.
Condition turns on the rim and the centre: chipped rims were often ground and filled by later hands, and enamel lost from the centre cannot be brought back.
