For example, in the battle of Wei destroying Shu in 263 AD, Wei coach Zhong Hui led 1.8 million Wei soldiers to attack Shu Han in three ways, among which Zhong Hui's headquarters attacked Hanzhong in three ways. Zhong Hui did not capture Seoul and Lecheng in Hanzhong, leaving only the besieged troops. Zhong Hui led the main force to pursue Jiang Wei directly south.
In addition to Zhong Hui's giving up attacking Han and Le cities and turning to attack the rear area, Wargo did the same at that time. Wargo bypassed Jiange, sneaked through the level tone path, and went straight to Fucheng and Mianzhu, finally forcing Shu Han to surrender. This is a classic surprise attack, going around the city and hitting the rear directly.
On the basis of ensuring the provision of grain, Zhong Hui and Wargo unexpectedly won the war, but not every time they went around the city, they won.
For example, during Zhuge Liang's first Northern Expedition, Zhuge Liang made Zhao Yun the main force to attract suspected soldiers from Cao Zhen and led his own army out of Qishan. At first, he surrounded Qishan Castle, but did not occupy it. He also left the besieged troops, continued northward, and sent Ma Su to guard the street pavilion. Zhuge Liang led the main force to attack Longxi.
As a result, Ma Su was defeated by Zhang He in Jieting, and the Shu army lost its stronghold in Jieting. Zhang He led a great army to continue south. If Zhuge Liang didn't retreat in Longxi, Zhuge Liang's way home and supply lines would be breached by Wei Jun, and Zhuge Liang fighting in Longxi would be alone.
Zhuge Liang bypassed Qishan Castle and went to Longxi, but Zhang He's army was defeated by Jieting Shu Army, which made Zhuge Liang's first northern expedition meaningless and ended in failure. This is Zhuge Liang's failure to attack the city.
Therefore, not every ideal city can be bypassed. Whether it is necessary to go around the city depends on the actual situation and geographical location at that time.
The ancients were very particular about building cities, and they wouldn't just find a place to build them. Quite a few ancient cities have played the role of guarding strategic locations and building cities to take power.
For example, during the Three Kingdoms period, the road from Jingzhou to Yizhou, whether by water or land, had to enter Yong 'an City of Yizhou from Wushan, a county in the south of Jingzhou. This is the only way. After the demise of Shu Han, Soochow wanted to fish in troubled waters and sent tens of thousands of troops to attack Yong 'an City, which was guarded by only a few thousand people. At that time, the commander of Yongan garrison, Luo Xian, resisted desperately, and thousands of people only repelled the repeated attacks of tens of thousands of people.
It is impossible to bypass a city with strategic thoroughfares like this. To go there, you must win the city, which is impossible to bypass.
Cities built in strategic locations and Hangu Pass during the Warring States Period, if the six eastern countries want to attack Qin, they must seize Hangu Pass. For hundreds of years, the six eastern countries only broke the Hangu Pass once. At that time, it was impossible to bypass it, and it was necessary to attack Qin.
Although there is more than one Hangu Pass in the Guanzhong area where Qin is located, there is Pubandu, where Ma Chao fought Cao, in the north of the Yellow River, and Wuguan, where Liu Bang entered Guanzhong, in the south.
Although it was determined by the geographical environment at that time, it was determined by the will of commanders on both sides of the war. Generally speaking, there are few wars around the city, and it is difficult to win. The battle of Wei destroying Shu mentioned earlier is also largely due to the strength gap between the two sides.