During the mid-Spring and Autumn period, Chu dominated the region. When King Zhuang of Chu learned that Song, caught between Chu and Jin, had allied with Jin for its own benefit, he was furious and ordered his ally Zheng to attack Song.
At that time, Duke Mu of Zheng was in power, so he ordered his chief minister, Prince Guisheng, to lead an army to attack the State of Song.
The Zheng army marched into Song territory, where the Song generals Hua Yuan and Lü Le took command as chief and deputy, leading their troops to the front at Daji to meet the enemy.
On the eve of battle, Hua Yuan killed a sheep to boost morale. The soldiers feasted joyfully. Hua Yuan's deputy noticed that only his charioteer, Yang Zhen, sat gloomily outside the tent and asked, "General, why haven't you invited your charioteer to the feast?"
When the deputy general suggested including the charioteer in the war council, Hua Yuan scoffed, "Him? He's just a driver. What use is he in battle? Why bother letting him join?" The deputy tried to persuade him further, but Hua Yuan's face hardened as he declared, "Today's decisions are mine alone. Say no more." Outside the tent, the charioteer Yang Zheng overheard their exchange and muttered bitterly, "Fine, Hua Yuan. Tomorrow on the battlefield, I'll show you exactly what I'm capable of."
The next day, the decisive battle between Song and Zheng began. Hua Yuan rode in the chariot driven by Yang Zhen, commanding his troops. The Zheng army attacked fiercely, while the Song forces resisted with all their might. The clash was intense, and for a time, neither side could gain the upper hand.
Hua Yuan ordered Yang Zhen to drive the chariot toward the weaker right flank of the Zheng army, so he could command the Song forces to first break through there. Yang Zhen, however, did the opposite, whipping the chariot toward the strongest left flank. Hua Yuan shouted, "Yang Zhen, why aren't you following orders?"
Yang Zhen said coldly, "Yesterday, you decided how to divide the mutton; today, driving the chariot is my decision. This is called each governing their own affairs! Let me show you whether I am useful in battle."
With that, Yang Zhen had already driven the chariot to the left flank. Zheng soldiers swarmed in, surrounded Hua Yuan, and captured him alive. Seeing their commander taken prisoner, the Song army fell into chaos and ultimately suffered a devastating defeat.
The author of the Zuo Zhuan commented after recording this event, "Yang Zhen, for a personal grudge, brought disaster to the country and its people—a heinous crime!" Later, the idiom "each goes his own way" came to describe people acting according to their own will, disregarding the collective interest and refusing to cooperate with others.
Source: *Zuo Zhuan*, "Duke Xuan, Year 2"
Meaning of the Idiom: Later, the Chinese idiom "各自为政" came to describe people acting according to their own will, disregarding the collective interest and refusing to cooperate with others.