Chinese Idiom: 因势利导 (Yin Shi Li Dao)
English Translation: Guiding according to circumstances
pīn yīn: yīn shì lì dǎo
Idiom Meaning: This idiom refers to the principle of guiding and promoting actions based on the current trends and developments of a situation. “因” (yīn) means to follow, “势” (shì) refers to trends or circumstances, and “利导” (lì dǎo) means to lead or guide effectively.
Historical Source: “Records of the Grand Historian” (《史记 · 孙子吴起列传》)
Idiom Story:
In 341 BCE, during the Warring States period, the State of Wei allied with the State of Zhao to attack the State of Han. In response, Han sought help from the State of Qi, which appointed Tian Ji as the general and Sun Bin as the military strategist, leading an army of fifty thousand troops to provide assistance.
Despite being outnumbered and facing a long journey, the Qi army, following Sun Bin’s strategy, did not advance into Han territory directly. Instead, they launched a surprise attack on Wei’s capital, Daliang (present-day Kaifeng, Henan). Upon hearing of this, Wei’s general, Pang Juan, hurried back to defend the capital.
As the Qi army entered Wei territory, Sun Bin advised Tian Ji to take advantage of the situation: “The soldiers of the Three Jin states (Han, Zhao, Wei) are brave and often look down on Qi, believing them to be cowardly. A skilled commander must adapt to the situation and lead effectively.” He quoted from military texts, explaining that if the army’s supply line is too long, the commander risks losing troops.
Sun Bin suggested that they create multiple campfires to simulate a larger army: on the first day, they would set up one hundred thousand cooking stoves, on the second day, fifty thousand, and on the third day, thirty thousand. This would give the impression that the Qi army was growing in strength and morale.
Pang Juan, upon seeing the Qi camps, mistakenly believed that the Qi soldiers were fleeing. He felt overconfident and decided to pursue them with only eight thousand elite cavalry, ignoring the potential dangers of the terrain.
Sun Bin calculated Pang Juan’s marching speed and anticipated that he would arrive at the narrow and dangerous Ma Ling pass at night. He advised Tian Ji to prepare an ambush, using tree branches and stones to block the path. They also made a sign saying, “Pang Juan dies here,” and concealed a thousand archers along the route.
That night, Pang Juan arrived at Ma Ling, unaware of the trap. When he saw the sign, he ordered a light to read it. Before he could comprehend the message, the Qi archers unleashed a volley of arrows, throwing the Wei army into chaos. Recognizing his defeat, Pang Juan took his own life.
The Qi army, taking advantage of the situation, annihilated the Wei forces and captured the Wei prince. Sun Bin’s strategy and the principle of “因势利导” brought him fame, showcasing the importance of guiding actions according to the prevailing circumstances.