Zuo Tang Zong, a famous soldier in the late Qing Dynasty, entered the customs triumphantly after conquering Shaanxi and Gansu. That night, the garrison was stationed in a certain place, and just after the camp was set up, Zuo suddenly ordered: leave the camp immediately and move on! At that time, all the soldiers in the army were exhausted and wanted to have a good rest, so no one wanted to move any more. People came to Zuo Daying and asked Zuo to claim his life. Zuo was furious and said, "I'll get on my horse and start. Whoever dares to disobey orders and who dares to fall behind will engage in military law! " Left's military orders are extremely strict. Although the soldiers were angry, they had to dress up, and the whole team followed closely and walked in the dark. After two hours, I turned left and asked the generals around me, "How many roads have we walked?" The general said, "It's more than forty miles from the former camp." Zuo nodded and said, "OK, let's camp here."

Shortly after these people continued to rest, they suddenly heard an explosion behind them. After a while, the patrol of the back team came to Shuaiying and reported: "The place where we camped before was suddenly bombed and has fallen into a huge pit." As a result, the officers and men of the whole army were terrified, grateful and admired the left commander.

The generals asked Zuo how he predicted the disaster. Zuo replied: "I just sent troops at that time, and it suddenly occurred to me that although those leaders surrendered, they were also forced by our military strength." Not everyone really surrendered, and some people will definitely hold a grudge and retaliate, and the place where we stationed our troops for the first night was as early as they expected. Later, when the army beat the drums, I listened attentively again. There seems to be a response on the ground, like a hole in the ground, and I immediately ordered to avoid it quickly. What is certain now is that there is not only a hole in the ground, but also a lot of sulfur powder hidden in it. However, at that time, because of uncertainty and fear of causing panic, I didn't make it clear. "