Its northwest is Xiaoguan, located at the Liupan Mountain Pass, which can effectively defend the enemy from the northwest. Its west direction is Dasanguan, which is near Baoji now. Located at the junction of Sichuan and Shaanxi, it is the only way for Shaanxi to reach Hanzhong, Sichuan and Sichuan. South of it is Wuguan, located in Qinling Mountains, which is the only way for the ancients to enter Guanzhong from Hubei and Henan. To its east is the most important and world-famous Hangu Pass, which later became Tongguan Pass. Anyone who has been to Tongguan is shocked by the complicated terrain. Because it is related to Guanzhong, it is not an exaggeration to call it the first pass in China. Tongguan is the enemy's favorite way to enter Guanzhong from Shanxi and Henan. There have been more than a hundred wars here.
During the Warring States Period, the State of Qin blocked the pace of the armies of the six eastern countries with the help of Hanguguan. During the War of Resistance against Japanese Aggression period, although the Japanese occupied the whole eastern China and even Southeast Asia, they never dared to set foot in Shaanxi. There is no doubt that Guanzhong's unique geographical advantages have played a great role.
After the war in Wuhan, China and Japan entered the stage of strategic stalemate, and the Japanese army wanted to directly attack the National Government to attack Chongqing by going south to Sichuan and Shaanxi Sichuan. At the end of 1938, they attacked Yongji, a major town in the south of Shanxi, and then the Japanese army sent planes to bomb Tongguan every day. The elite troops of the Kuomintang garrison sent five divisions to defend Tongguan, which made the Japanese army look and sigh, and dared not cross the line. After Japan captured Pearl Island, the war situation in Southeast Asia has developed greatly, and they also want to March into Shaanxi when morale is high. The national army suffered heavy losses in the battle of Zhongtiaoshan, but the Japanese army still dared not enter Tongguan easily, because our Eighth Route Army quickly established a base area behind enemy lines and could cut off the Japanese logistics supply line at any time. After 1942, the overall situation of World War II changed dramatically. The American army won a great victory in the island-jumping battle in the Pacific battlefield and gradually approached Japan. The Japanese army had no extra troops to attack Shaanxi. He had to put the elite troops into the Pacific battlefield to fight with the American army, which was one of the reasons why it was difficult for the Japanese army to set foot in Shaanxi.