In ancient China, beginning of winter was divided into three stages: the beginning of still water and ice; The second waiting place began to freeze; Waiting for the flood is a cockroach. "This kind of solar water can already form ice; The land also began to freeze; In the third stage, pheasant refers to a big bird similar to pheasant, and pheasant is a big clam. After beginning of winter, big birds like pheasants were rare, but you can see big clams with similar lines and colors at the seaside.