In 207 BC, the Qin Dynasty's rule was overthrown by surging peasant uprisings, igniting a fierce war for supremacy between Liu Bang and Xiang Yu.
In the early stages of the Chu-Han conflict, Liu Bang was no match for Xiang Yu, suffering repeated defeats. The Battle of Pengcheng was especially devastating—his parents and wife were captured by Chu forces during the escape. Nearly losing hope, Liu Bang asked his strategist Zhang Liang:
“You see, to whom should I give the lands east of Hangu Pass to make them achieve great deeds for me?”
Zhang Liang advised that the great general Han Xin was a brilliant strategist, the King of Jiujiang, Ying Bu, had a falling out with Xiang Yu, and the Prime Minister of Wei, Peng Yue, was exceptionally fierce—so these three were the best candidates for the imperial gifts. Following Zhang Liang's counsel, Emperor Liu Bang promoted Han Xin, allied with Peng Yue, and turned Ying Bu against Xiang Yu, drastically weakening Xiang Yu's power.
In 203 BC, Xiang Yu was forced to negotiate a truce with Liu Bang. Xiang Yu released Liu Bang's parents and wife back to the Han camp, then led his troops eastward. Liu Bang also prepared to return to Guanzhong. At this moment, Zhang Liang advised him:
"Xiang Yu is now completely exhausted and unable to fight. This is the perfect opportunity to destroy him. If we let him go now, it would be like releasing a tiger back into the mountains—endless trouble will follow."
Impressed by Zhang Liang's reasoning, Liu Bang pursued the Chu army. To ensure total victory, Zhang Liang advised Liu Bang to grant the lands east of Chen and Suiyang to Han Xin and Peng Yue, securing their full support. This strategy led to a decisive defeat of the Chu forces at Gaixia, where Xiang Yu took his own life, and Liu Bang finally established the Han Dynasty.
After destroying Chu, Liu Bang gathered his ministers in Luoyang to discuss merits and rewards. Before the assembled officials, he said, "Zifang (Zhang Liang) never fought on the battlefield, but by strategizing within the command tent, he secured victory a thousand li away, achieving extraordinary merit."
Liu Bang immediately declared he would enfeoff Zhang Liang with thirty thousand households. Zhang Liang humbly declined. In the end, Liu Bang enfeoffed him as the Marquis of Liu.
Later, people used the idiom "strategizing within the tent" to refer to planning and employing winning strategies within a military command tent.
Source: *Records of the Grand Historian*, Chapter "Annals of Gaozu"
Meaning of the Idiom: Later, the Chinese idiom "运筹帷幄" came to describe planning and employing winning strategies within a military command tent.