During the Spring and Autumn period, Duke Huan of Qi appointed the brilliant Guan Zhong as his prime minister, driving sweeping reforms that strengthened the state and made Qi the first great hegemon of the era.
In 663 BC, the northern Shanrong kingdom invaded Yan, prompting Yan to seek help from Qi. Duke Huan of Qi personally led a massive army to the rescue, accompanied by his brilliant strategist Guan Zhong and another advisor, Xi Peng.
When Duke Huan of Qi's army arrived in the state of Yan, the Shanrong forces had already plundered much wealth and fled east to the Guzhu kingdom.
Duke Huan of Qi said to Guan Zhong, "The Shanrong have fled upon hearing I led the army myself. Let us withdraw and return." Guan Zhong pondered a moment and replied, "Once we leave, the Shanrong will surely raid again. Better to pursue them and seize the opportunity to destroy Guzhu, securing the northern border."
Duke Huan of Qi, finding Guan Zhong's reasoning sound, ordered the army to press eastward in hot pursuit.
When the Qi army pursued the enemy to the Guzhu Kingdom, they found no resistance at all—the Guzhu king and the Shanrong king had both fled in terror upon hearing of their approach, leaving the capital an empty city.
Duke Huan of Qi, unwilling to have pursued them in vain, ordered his army to press onward, determined to capture the kings of Guzhu and Shanrong and eliminate the threat once and for all.
The Qi army pressed on in pursuit, ultimately securing victory, quelling the border troubles, and finally returning to Qi.
The Qi army had set out in spring, but by the time they returned victorious, it was winter, and the landscape had completely transformed. Marching through a valley in the rugged mountains, they eventually lost their way. Scouts were sent out in waves—some vanished, never to return; others came back but couldn't describe the correct path. As days passed, the army's supplies ran low.
At this critical moment, the quick-witted Guan Zhong calmly pondered. He reasoned that dogs could find their way home from afar, and horses—especially old ones—must possess the same remarkable instinct. Turning to Duke Huan of Qi, he said, "Your Majesty, I believe old horses have a knack for recognizing the road. Let us select a few to lead the way, and they will guide our army out of this valley."
Duke Huan of Qi immediately agreed, and Guan Zhong personally selected a few old horses, loosened their reins, and placed them at the very front of the column without urging them on, letting them wander freely. Following the old horses, the troops meandered east and west until they finally emerged from the valley and found the main road back to the state of Qi.
Later, people used the idiom "an old horse knows the way" to describe experienced individuals who are familiar with a situation and can provide guidance in a certain area.
Source: *Han Feizi*, "Shuo Lin Shang"
Meaning of the Idiom: Later, the Chinese idiom "老马识途" came to describe experienced individuals who are familiar with a situation and can provide guidance in a certain area.