Guan Zhong quoted the original text as saying: "Guan Zhong and (xi) friends cut solitary bamboo from Huan Gong, and spring came back to winter, and they lost their way. Guan zhong said:' the wisdom of an old horse can also be used.' Is to let the old horse go and get the way. Although countries in the Central Plains gradually recognized the status of Qi as the leader, some ethnic tribes living in remote areas ignored this article. One day, Qi Huangong was discussing with Guan Zhong when someone came to report that róng, a northern minority, had invaded Yan State again and robbed food, livestock and property. Yan sent for help. Qi Huangong asked Guan Zhong for advice. Guan Zhong said, "Rongshan always disturbs the Central Plains, which is a worry for the stability of the Central Plains and must be conquered." Qi Huangong listened to Guan Zhong and led an army to save Yan. When Qi Huangong's troops arrived at Yanyuan, they realized that Shan Rong had fled with the robbed population and property. Guan Zhong said, "Although Dan Rong has escaped, he will come to harass again. We might as well chase them to the end and completely defeat them in order to achieve long-term stability in the north. " Qi Huangong listened to Guan Zhong's advice and pursued Shanrong to the north. Yan Zhuanggong, the monarch of the State of Yan, said to Qi Huangong, "There is an endless country nearby (now yutian county, Hezhou) that has always been in contact with us. They also had a grudge against Shan Rong. Can you ask them to lead us to attack Shan Rong? " Qi Huangong immediately sent someone with a gift to a country without a dock for help. Endless countries also sent troops to participate in the war. The leader of Shanrong is called Milu. He heard that Qi, Yan and Wu Dong were fighting together, but he knew that he could not defeat them, so he fled to the north with some cronies and treasures. The soldiers and civilians who had no time to escape surrendered. In order to convince Shan Rong, Qi Huangong ordered not to hurt Shan Rong's soldiers and people. Dan Rong was treated leniently and thanked Qi Huangong. Qi Huangong asked them, "Where did the leader of your go?" They said, "I must have gone to the lonely bamboo country to borrow soldiers." Qi Huangong decided to attack the Milu deer, conquer the solitary bamboo country, and completely eliminate the hidden trouble of northern unrest. Besides, Milu fled to a remote bamboo country and asked the monarch for help. In reply, he sent General Huang Hua to lead his troops and the Milu to face the Qi army. Unexpectedly, Huang Hua was defeated by the Qi army as soon as he came out. Huang Hua fled back and said to Li He, "Qi Huangong led an army to attack the milu deer, which has nothing to do with our country. I think it's better to kill the milu deer and make peace with Qi Hou, so as to save ourselves. " Another minister made a suggestion: "There is a place in the north called' Dry Sea' and' Lost Valley', where the desert is vast and the roads are difficult to distinguish. If the Qi army can be introduced into the "lost valley", it is possible to annihilate the entire army of Qi and Hou with one soldier. Huang Hua was moved. So he went to kill the milu deer, cut off his head, and presented the milu deer's head to the army of Qi Hou, saying that Arija led the army to escape, and he was willing to yield to Qi Hou, lead the way for the Qi army and pursue Arija. When Qi Huangong saw that Huang Hua offered the head of the milu deer, he believed it and led a large group of people to chase after Huang Hua northward. Huang Hua led the way, and Qi Hou's troops followed. After entering the desert, I just turned a few corners and couldn't find my way. The vast yellow sand (yín) is like a quiet sea, which can't tell the east, west, north and south, nor can it tell the front, back and left. Qi Huangong wants to ask Huang Hua what is going on, but where is his shadow? Only then did I know that I had been cheated by Huang Hua. At this time, the sun has set and the night has covered the earth. It was dark all around, and the northwest wind kept blowing, making the soldiers tremble with cold. Very not easy to wait until dawn, only to find that people have dispersed. Qi Huangong ordered to find a way out quickly, but a large group of people were wandering around, and they couldn't get out of this mysterious valley. At this moment, Guan Zhong suddenly remembered that most old horses knew the way home, so he said to Qi Huangong, "Old horses know the way. Many horses without a final country belong to Shan Rong. It is better to choose a few old horses without a final country and let them go ahead. Maybe you can find a way out. " Although Qi Huangong was skeptical, there was no other way. He agreed to give it a try. So Guan Zhong picked a few old horses and let them walk in front, followed by a large group of people. Several old horses walked unhurriedly, and sure enough, they walked out of the valley and returned the same way. Everyone had a narrow escape and admired Guan Zhong's resourcefulness. Since then, "an old horse knows the way" has also become a widely circulated idiom. The Qi army went out of the valley and defeated the solitary bamboo country. A Li He and a Huanghua were also killed by the mutinous soldiers, and the lonely bamboo country was destroyed. After the victory, Qi Huangong said to Yan Zhuanggong, "There are 500 kilometers of land around Shanrong and Solitary Bamboo. I will give it all to you. " Yan Zhuanggong said quickly; "It's not a big deal. Thanks to your help, we saved our land. Now we are very grateful. How dare we take your land? " Qi Huangong said, "You're welcome. The northern border is very important. You should take care not to let the border people invade and pay tribute to the heavenly king. This is an honor for all of us. Besides, Qi is so far away from here that it is beyond the reach of the whip and can't be managed! " So on say, Yan Zhuanggong is not good to refuse. On the day when Qi Huangong led his troops back to China, Yan Zhuanggong personally saw him off. Along the way, the two chatted and walked, and the more they talked, the more speculative they were, and they unconsciously went out of the border of Yan. Until they parted, Qi Huangong suddenly remembered Zhou Li's rules and said, "Since ancient times, governors have forbidden sending princes abroad. How can you violate the rules? " He said he would cede fifty miles of land to Yanyuan. Yan Zhuanggong has got 500 Li of land. He won't take another 500 Li from Qi, but he is determined to be recognized as the overlord. He keeps his word and obeys the rules, so he has to accept it. In this way, Yan got five miles of fertile land. When all the governors saw that they personally led the army to save Yan and won the battle, they were not greedy for land, and no one did not obey him from the heart. Since then, Qi Huangong's prestige as the overlord has been even higher.