Why is the mountain south and the water north "Yang"? What is the basis?

The saying that "the mountains in the south are sunny in the north and the mountains in the north are cloudy in the south" mainly originated from the Central Plains, that is, the Yellow River Basin. In the ancient Yin-Yang geomantic omen in China, dryness was called "Yang" and dampness was called "Yin", that is, the place that can be irradiated by the sun was called "Yang" and the place that cannot be irradiated by the sun was called "Yin".

Because geographically, the Yellow River basin is located in the north of the Tropic of Cancer, and the sun is in the south all the year round. In the east-west mountain range, the south of the mountain can be illuminated by the sun, which is called sunny slope, while the north of the mountain can't receive sunlight all the year round, which is relatively humid, so it becomes shady slope.

However, the branches and sections of the east-west rivers or rivers in China are located in the northern hemisphere, because under the influence of geostrophic deviation, the right bank is eroded and the left bank is piled up, that is, the south bank is eroded and the north bank is piled up. Therefore, the south bank is lower and wetter than the north bank, so it is difficult for sunlight to reach, and if there are peaks on the south bank, it will also block the sunlight that originally hit the south bank, so it is called shade. The north bank of the river can be illuminated by sunlight, so it is called Yang.

Take the Qinling Mountains as an example. The southern foot of Qinling Mountain is sunny all the year round, but there is no sunshine in the north. Therefore, the southern foot of Qinling Mountain is called Yang and the northern foot is called Yin. Take Huaishui as an example. The south bank of Huaishui is cloudy and the north bank is sunny. And the name of "Huaiyin City" came from this.

This concept of Yin and Yang has had a long-standing influence in China, and it has also become the basis for naming many place names in China. We all know Xianyang, but why is it called Xianyang? "salty" means "all" in ancient Chinese, and Xianyang means all yang. Xianyang is located in the north of Weishui River, nine miles away from Shan Zhinan, and the mountains and rivers are sunny, so it is called Xianyang. Huayin County is famous for its old Huayin accent. Huayin County is located in the north of Huashan Mountain, so it is called Huayin. According to this principle, we can also infer the local geographical environment from these place names.

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