From a defensive point of view, Chengdu, Sichuan Province, as the capital of the Shu state in the past, has many gateways, such as the farthest Shaanxi Hanzhong, the nearest point of Sichuan Guangyuan, Jianmenguan, Jiangyou, and the nearest point of Mianyang, Mianzhu, Shifang are all. If you say that the closest gateway to Chengdu is important, you may have to say Guanghan.
In Sichuan Province, as a county-level city under the jurisdiction of Deyang, Guanghan is not well known, and may not be as good as Deyang. But Guanghan's biggest advantage is that it is too close to Chengdu, one of the central cities in the southwest, that is, about twenty kilometers. If any city can be called the northern gate of Chengdu, Guanghan is obviously the most appropriate.
There are many reasons why the Shu state has been located in Chengdu for many reasons, one of which is the geographical defensive advantage. If the northern army attacked south from the direction of Hanzhong, it would need to pass through many mountains and rivers, as described above. Even if the southern army attacked west from the direction of Fengjie, it was also far away, and Chengdu was relatively safe at the westernmost point of this great triangle. If the northern fortresses of Hanzhong, Micangshan, Guangyuan, Jiange, and Guanghan are called the "nine lives" of Chengdu, then Guanghan can undoubtedly be regarded as the "ninth life" of Chengdu. The ninth life was gone, and Chengdu lost its defensive significance in front of the Northern Army.
In the sixteenth year of the Eastern Han Dynasty's Jian'an (211 AD), The Jingzhou Mu Liu Bei was invited into Shu by Liu Zhangzhi, nominally defending Zhang Lu in Hanzhong, but actually taking Shu. After Erliu turned his face, Zhang Ren and other troops of the Yizhou army retreated to Luocheng, and the Jingzhou army besieged the city in a big way. Then, Zhang Ren was killed in battle, but with Liu Bei's posture, he failed to take Luocheng. Luocheng is now Guanghan, which was the seat of guanghan county during the Eastern Han Dynasty. At that time, the jurisdiction of Guanghan County included Guangyuan, Mianyang, Deyang, Suining and other areas, and the reason why Guanghan County placed its seat of governance in Luocheng (hereinafter the same as the present-day Guanghan City of Sichuan Province) was roughly considered. Luocheng is too close to Chengdu, and the county government can support Chengdu near luocheng, and the two cities are angled to each other, and the terrain of Luocheng is relatively complicated.
The Tang Dynasty people believed that there were three Shu in Shu, which three Shu? Chengdu, Zitong, Guanghan. From the perspective of the Tang Dynasty, Zi Tongdang is now the dangerous road from Mianyang to Guangyuan, including the Sword Gate Pass, which is known as the world's most dangerous sword. Needless to say, Chengdu is located in the transition zone between the Qinghai-Tibet Plateau and the Sichuan Basin, and it is also the land of the Tuojiang River and the Minjiang River, and the place where the mountains and rivers are dangerous. Guanghan lived between Chengdu and Zitong, the two Shu, and played a role in connecting.
Liu Bei soldiers surrounded Luocheng, as long as they took Luocheng, Chengdu was in front of them. What Liu Bei did not expect was that he did not take Luocheng for a whole year, but instead folded Pang Tong, the most important strategist who entered Sichuan this time, and died in the middle of the stream. Pang Tong's death had a very significant impact on the future trend of the Shu Han Dynasty, or on the trend of the entire history of the Three Kingdoms. Some analysts believe that if Pang Tong did not die in Luocheng (Guanghan), Zhuge Liang would not have to leave Jingzhou, then Sun Quan would not have much possibility of sneaking into Jingzhou, and there would be little chance of success if he sneaked in. Because of Pang Tong's death, Zhuge Liang was under Luocheng, so he had to take Zhang Fei and Zhao Yun, the two most important military generals of Liu Bei's clique, into Sichuan and threw Jingzhou to the arrogant Guan Yu, which ended in messing up Liu Bei's great cause of competing for the world. In other words, Sun Quan's sneak attack on Jingzhou (the west) was successful, which laid the pattern of the three kingdoms standing side by side in the true sense, and no one could eat anyone anyway. Prior to this, the rapid expansion of Liu Bei's clique had made Cao Cao and Sun Quan feel a great threat to their survival, and Cao Sun had joined forces to eliminate Guan Yu.
We can say that although Luocheng (Guanghan) was small, it inadvertently changed the direction of the history of the Three Kingdoms. Of course, when Liu Bei was full of pride in capturing Luocheng, he couldn't imagine what would happen in the future that would make him unforgettable. After Liu Bei took control of Shuzhong, he felt that Guanghan County was too big, so he left Zitong County from the northern part of Guanghan County. However, Luocheng is still the seat of the shrunken version of Guanghan County, and it is still the most important northern gate of Chengdu.
How important is Guanghan to Chengdu, the ancients said: "Luocheng lives in the upper reaches of Chengdu, and if You get Luocheng, you get Chengdu, and if You lose Luocheng, Chengdu does not defend." Youyun: "Those who have competed for Shuzhong in the past will die for guanghan." The People of the Jin Dynasty saw very clearly the significance of the Guanghan dynasty to Chengdu, "The land of the throat of Yizhou, the key to Chengdu's gains and losses." Fifty years after Liu Bei entered Shu, in 263 AD, the Wei general Deng Ai killed Zhuge Liang's son Zhuge Zhan at Mianzhu, and then led his army straight into Luocheng, and the later lord Liu Chan had no way to escape.
Photo - Overlooking Guanghan City, Sichuan
In the middle of the Five Dynasties and Ten Kingdoms, when the Later Tang Dynasty destroyed Later Shu, and when the Tang army entered the Guanghan Dynasty, which was called Hanzhou, wang Yan, the lord of former Shu, also had no way to retreat. The subsequent Later Tang general Meng Zhixiang (孟知祥) was in charge of Shu, and dongchuan (東川節度) made Dong Chuan compete for Shu land, and Hanzhou was also a key fortress for Meng Zhixiang to retreat to defend Chengdu and attack Dongchuan. In the early years of the Ming Dynasty, the general Fu Youde attacked Chengdu, also taking Hanzhou first, and Chengdu surrendered. Therefore, Gu Zuyu, a geographer in the early Qing Dynasty, said: "Hanzhou has the potential of lips and teeth in Chengdu." As the "lips" of the Guanghan Dynasty, as the "tooth" chengdu cold, can be called a glory and a loss.