Gan Mao's Attack on Yiyang: A Key Step in Qin's Unification of the Central Plains

Brief Introduction

Gan Mao was a distinguished politician and military strategist of the Warring States period, serving both the States of Chu and Qin. During the reigns of King Huiwen and King Wu of Qin, he served as Chancellor and led the famous "Attack on Yiyang." This battle was not only a classic case in Qin's military history but also a critical turning point for Qin's expansion from the Guanzhong region into the heartland of the Central Plains. Gan Mao's strategy and willpower provide essential material for studying Warring States military and diplomatic affairs, serving as a key window into understanding the process of Qin's unification of the six states.

Core Knowledge Points

1. Strategic Intent: Yiyang was a key stronghold in western Han, located at a strategic chokepoint for Qin's eastward expansion, controlling the route to Luoyang, the seat of the Zhou Royal Court. Gan Mao argued that capturing Yiyang would allow Qin to "connect with the Zhou Court," thereby threatening the heartland of the six eastern states. This was an early practice of Qin's "befriend distant states, attack nearby ones" strategy, aimed at breaking geographical blockades and extending influence into the Central Plains.
2. Art of Persuasion: Faced with King Huiwen's hesitation regarding the difficulty and distance of the war, Gan Mao cited the allusion of "Liu's Forgotten Shoe." He recounted the story of a man from Lu who forgot his shoes upon leaving home but refused to return because the journey was too long. He used this to analogize war decisions, emphasizing that once a decision is made, it cannot be changed midway. This firm stance bolstered the king's confidence and secured full support.
3. Battle Process: The war was exceptionally fierce, lasting five months. Qin suffered heavy losses, losing five generals in succession, before finally breaching Yiyang and beheading 60,000 enemy soldiers. Although the cost was high, this victory thoroughly opened the gateway to the east and forced the States of Han and Wei to submit.
4. Historical Impact: After the attack on Yiyang, Qin's influence penetrated the Central Plains for the first time. This provided strategic space for the conversion of national strength following Shang Yang's reforms, marking Qin's official rise as the hegemon of the Central Plains and laying the foundation for subsequent unification.

Connection with the Content of "Records of the Grand Historian"

In the Records of the Grand Historian · Biography of Chu Li Zi and Gan Mao, Sima Qian detailed Gan Mao's life and the course of the attack on Yiyang. The text not only records the details of the battle but also portrays Gan Mao as a "think tank." By describing how Gan Mao gauged the monarch's psychology and maintained strategic resolve amidst difficulties, Sima Qian indirectly reflects the characteristic combination of diplomatic strategists (Zongheng Jia) and military generals during the Warring States period.

Furthermore, the Records of the Grand Historian notes that Gan Mao was forced to flee to the State of Wei after the war due to slander. This detail adds complexity to the historical narrative. Sima Qian uses this to imply that although Qin was powerful, internal political struggles remained intense, and meritorious officials did not always end well. Gan Mao's story validates the historical view in the Records of the Grand Historian that "those who gain people prosper," while also warning future generations that high merit often accompanies political risk. Through this chapter, readers can gain a deeper understanding of Qin's talent strategy and military layout during the unification process, as well as Sima Qian's profound insight into the fate of historical figures.