Must the river be open in July and September?

79 is not necessarily a river. The geese in the 79 River mean that the ice in the 79 River begins to thaw. In fact, the ice in the river only began to melt, and it did not completely open the river. Similarly, there were no wild geese in the sky in 1989, and they were preparing to fly back to the north, so the temperature in all parts of the country was still low.

The background of Jiujiu songs

Jiujiusong is a popular folk formula for calculating the date and weather changes in China. In winter solstice, it is also called Jiujiu Jiehan Song, commonly known as Jiujiu Song, which vividly records the climate and phenological changes between winter solstice and vernal equinox, and also expresses some laws of farming activities.

In ancient times, especially in the north of China, the working people had simpler conditions to keep warm from the cold than their descendants. They regarded the cold winter as a threat and punishment, which directly affected people's mood and even made them feel that winter was inexplicably long. At that time, the people of China invented the method of counting nine to entertain themselves.