What are the three stages of beginning of winter in ancient China?

In ancient China, beginning of winter was divided into three stages: "In the first stage, water began to freeze; The second waiting place began to freeze; The pheasant waited for three days, and the water was a mirage. "

This solar water can already form ice; The land also began to freeze; The pheasant in the third stage of "pheasant makes water a stork" refers to a big bird like pheasant, and the stork 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. Therefore, the ancients thought that pheasants would become big clams in early winter.