There are many intersections between Hanzhong and Sichuan in history, which are essentially determined by geography. Turning to the map of China, we can see that there are natural dividing lines between the east, west, north and south of China.
Qinling Mountains and Huaihe River are the dividing lines between north and south of China, while Taihang Mountain, Three Gorges and Wuling Mountain are the dividing lines between east and west of China. In this big pattern, Hanzhong City and Sichuan Province belong to the southwest of China and are the "Liangzhou" of Kyushu, Gong Yu.
Liangzhou is a geographical concept, that is, the ancient Zhongyuan people collectively referred to the southwest territory. In the southwest territory, Hanzhong, Ba and Shu were first included in the Chinese territory.
Extended data:
Whether in geography, climate or cultural scenery, Hanzhong is closer to Sichuan, but it is very different from Guanzhong, so it seems that it should be included in Sichuan Province. The fact is that Hanzhong is in Shaanxi, which is a wonderful arrangement made by the rulers out of consideration of local regional checks and balances.
If the country wants to achieve long-term stability, it must fully consider the principle of regional checks and balances when dividing the first-level administrative regions.
When drawing provincial boundaries, we must first ensure that when any province wants to split independently in the future, the central government can control the fortresses in its neighboring areas to hold its handle, so as to achieve the purpose of maintaining stability and suppressing it.
Secondly, even if the separatist forces fail to suppress, we must ensure that the separatist provinces are frustrated and cannot survive alone.
References:
Baidu encyclopedia-Hanzhong