In 219 (the twenty-fourth year of the Eastern Han Dynasty), after the Shu Han had spent nine cattle and two tigers to take Hanzhong from Cao Cao, Liu Bei's next personnel arrangement was more psychedelic. Sent to guard Hanzhong was the less famous General Wei Yan, not Zhang Fei, who had high hopes. Liu Bei's brother Zhang Fei was sent to Shuzhong to defend Brazil.
Hanzhong, located in the Hanzhong Basin, north of the Qinling Mountains, south of Daba Mountain, Micang Mountain, the tributary of the Yangtze River Han River through the city. To the north of the Qinling Mountains is the Guanzhong Plain, where the ancient capital of Chang'an is located; south of Daba Mountain and Micang Mountain is the Sichuan Basin, which is known as the kingdom of Tianfu. There are only a few roads from Guanzhong to the Sichuan Basin, such as Chencang Road (Gu Dao), Chu Chuan Road, Luo Luo Road, Meridian Road, Jinniu Road, Micang Road, Lychee Road, etc. The first four are the Shu Road from Guanzhong Plain to Hanzhong, and the last three are the Shu Road from Hanzhong to Sichuan.
Shu Dao is difficult, it is difficult to go to the blue sky. Sandwiched between the Guanzhong Plain and the Sichuan Basin, Hanzhong, due to its unique geographical location, has naturally become a place of contention for soldiers who are bordered by Yongliang in the north and Bashu in the south, and have the reputation of "hanzhong is the world". During the Spring and Autumn Period and the Warring States Period, the State of Qin used Hanzhong as a springboard to annex Bashu. When Chu and Han were fighting for hegemony, Liu Bang left Hanzhong and went north to attack Guanzhong, and finally won the world.
Cao Cao conquered Hanzhong and could cross the Daba Mountains at any time to attack Shu Han. The northern gateway of Hanzhong, bashu, was not in his own hands, leaving Liu Bei unable to sleep at night. Only by taking Hanzhong can we ensure that Shu Han has no worries. Later, the facts also proved this point, the direct cause of the final demise of Shu Han was Deng Ai's smuggling of Yinping, and the more important reason was that Shu Han lost Hanzhong.
Don't get me wrong, Brazil is not the Brazil of South America, but the Brazilian County in the Sichuan Basin at the end of the Eastern Han Dynasty. During the Warring States period, after the qin state destroyed the ba state, ba county was established, and Langzhong was a county. During the Eastern Han Dynasty, Ba County was divided into Ba County, Bashi County, and Badong County, and the seat of government of Bashi County was in present-day Langzhong City (nanchong City, Sichuan).
The scope of the Shu Han Dynasty's Bashi County was roughly as follows, bounded by Micang Mountain and Hanzhong County in the north, Daba Mountain and Shangyong County in the northeast, Guanmian Mountain, Jingjing Mountain and Badong County (Zhi chongqing Fengjie) in the east, and ba County (ruling Chongqing Fengjie) in the south, and the Western Han River (also known as Langshui, now Jialing River) running through the north and south. Located on the northern edge of the Sichuan Basin and in the middle reaches of the Jialing River, Junzhi Langzhong is surrounded by water on three sides and mountains on all sides, and is a scenic spot for the melting of mountains and rivers, which is easy to defend and difficult to attack.
The Shu Road between the Sichuan Basin and the Hanzhong Basin is bordered by Jinniu Road to the west, Micang Road to the middle, and Lychee Road (built during the Tang Dynasty) to the east. The Oxway is the main passageway, and it is necessary to cross the Jianmen Mountains from the Sword Pavilion, and the Sword Pavilion is the key. Jinmicang Road goes directly south from Hanzhong, over Micang Mountain and Daba Mountain, through Nanjiang, Bazhong to Langzhong, the route is roughly the same as S101. The Rice Barn Road is not easy to walk, but the distance is close, which is conducive to rapid attacks. Langzhong is located between the Jianmen Mountains and the Daba Mountains, and is the last and most important checkpoint of the Micang Road, which cannot be lost.
In contrast, although Brazil (Langzhong) is also very important, the Rice Cang Road is difficult to walk, and the enemy cannot use troops on a large scale, but can only surprise troops. From the perspective of grand strategy, Hanzhong's rank is higher than That of Langzhong, which is more important to Shu Han. If there was no gateway to Hanzhong, the Shu Han would at most be surviving, and it would only be a matter of time before it was destroyed, not to mention the Northern Expedition to the Central Plains and the Kuangfu Han Room.
Therefore, some people think that Liu Bei did not let Zhang Fei guard Hanzhong, indicating that he was jealous of Zhang Fei and did not want to reuse Zhang Fei, which was actually not right. Liu Bei's ability to recognize and employ people is beyond doubt, and wei Yanshou is more important in Hanzhong because Wei Yan's ability is stronger than Zhang Fei's. Wei Yan is a strategic talent, and he is steady and cautious.
Zhang Fei was Liu Bei's brother-in-law, and Wei Yan was Liu Bei's subordinate, and his loyalty was no worse than Zhang Fei's. Although Zhang Fei is brave and quick-witted, he has personality defects, such as liking to drink, drinking too much and whipping soldiers. Zhang Fei had a previous conviction for drinking and was eventually killed while drinking and whipping soldiers while defending Brazil (Langzhong).
In general, because of the importance of Hanzhong, there is absolutely no room for mistakes, and it is necessary to be absolutely safe to guard in order to be assured, wei Yan is undoubtedly the most suitable one at that time. Wei Yan was very domineering: "Cao Cao raised the army of the world, and I refused for the sake of the great king." Cao Cao sent 100,000 teachers to come, and I swallowed it for the king! "Wei Yan did a very good job in Hanzhong.