Another important reason is that even if we can reach the western region and develop there, regardless of logistics, it is difficult for Shu Han to fully grasp the western region. Many of China's foreign policies (such as paying too much attention to the demeanor of a big country, and not being ruthless enough in dealing with the problem of betraying the vassal states and even the Xiongnu in the western regions) have led to insufficient deterrent power to the western regions. At that time, the Han dynasty connived at the Huns to destroy a country loyal to itself, and also let the countries in the western regions leave Germany. More importantly, Shu Han is a famous Han Chinese, but it can only be said that it is a local government, and there is no reason for the western regions to submit. It is difficult to integrate multi-ethnic groups after the occupation, so we must first go to the Central Plains and control the western regions.