During the Three Kingdoms period, why didn't Wei take the initiative to attack Shu?

1, Cao Zhen hits Shu:? (Cao) It's true that he left Chang 'an in August and entered south from Ziwu Road. King Sima Xuan returned to Hanshui and became a member of Nanzheng. The army entered either from Gu Jie Road or from Wuwei. It will rain heavily for more than 30 days, otherwise the plank road will be broken Will those in Cao Zhen return to the army? .

After Zhuge Liang's first Northern Expedition, Alfred Cao Zhen was stationed in Chang 'an and divided into two groups. He personally led the army and prepared to attack from the meridian. Sima Yi is going up the Han River from Xincheng County. Cao Zhen attacked from north to south, and Sima Yi attacked from east to west, ready to meet in Nanzheng County, Hanzhong County, Yizhou. There are also two armies, ready to attack from Gu Jie and Wuwei counties.

But maybe at first, it rained heavily for 30 days in Shu, and the weather was not good. Even the plank roads were washed away in some places, probably because of mudslides, so Wei Mingdi wrote a letter and ordered all the troops to come back.

2. In the era of General Cao Shuang, Cao Shuang, the son of Cao Zhen, died ten years ago in 224. Five years ago (now), (Cao) Shuangnai went west to Chang 'an, losing 60,000 to 70,000 people and entering from Luogu. At that time, Guanzhong, Bianyi and Qiang were unable to supply. Many cows, horses, mules and donkeys died, and the people cried for directions. Travel a hundred miles into the valley, the thief is solid because of the mountain, and the soldiers are not allowed to enter? . Cao Shuang started it? Battle of logu? , aggressively into shu,? Fei Yi's invasion of Sanling was only a success. Those who run cattle and horses die slightly, and Qiang Hu complains and sighs, especially Guan knows its waste.

The road is difficult and dangerous, and the cattle and horses are difficult to transport, resulting in? Is this a waste of electricity? General Cao Shuang can only retreat. Is this in the reflection? Battle of logu? , here? Service? , not fighting, but? Labor? . General Cao Shuang entered Sichuan on a large scale, spending a lot of manpower and material resources, which not only made? Is this a waste of electricity? , but also led to Liang Yong and other places of ethnic minorities Qiang and conference semifinals extreme dissatisfaction.

In the late Three Kingdoms period, the long-term war in the late Eastern Han Dynasty led to economic recession, a sharp drop in population and a decrease in productivity. It is still difficult for Cao Wei to wage a large-scale long-term war.

At the same time, the main direction of Cao Wei was Sun Quan, especially when Zhuge Liang was alive, Shu and Wu Dacheng? To the world? Covenant, the two sides * * * with invasion, * * * Cao Wei. Zhuge Liang is not the main force, but Sun Quan is the main force to attack Cao Wei. Therefore, after repelling Sun Quan with personal expedition, Wei Mingdi said? With Sun Quan gone, Zhuge Liang is emboldened? Zhuge Liang had to withdraw his troops, and it did.

Moreover, the road into Sichuan is difficult and the weather is not good, which is not suitable for group army action. Cao Wei went to Sichuan twice, especially for the first time, because of the weather. After 30 days of heavy rain, the weather in Sichuan is not clear. Why? Shu dog barks at the sun? Say, maybe in ancient times, Sichuan was the same? Sunny for three days in a row? Yes

The right time and place enabled Wei to enter Sichuan twice, but all failed. At the same time, Wei continued to pursue the policy of Wang Lang, developing economy and population, and the two sides reached an impasse.