Lu Kang, a renowned general of the late Eastern Wu, was appointed as Jianwu Colonel at just twenty, commanding the five thousand troops left by his father, Lu Xun. In 264 AD, the Wu ruler Sun Hao promoted him to Grand General of the Pacification Army.
In 272 AD, Bu Chan, the Eastern Wu general guarding Xiling, defected to the Jin dynasty. Sun Hao immediately dispatched Lu Kang with an army to suppress the rebellion. With masterful strategy, Lu Kang swiftly captured Xiling and executed Bu Chan.
When Sun Hao learned of this, he praised Lu Kang highly and, believing the Eastern Wu kingdom was powerful enough, attempted to contend with the Jin dynasty for supremacy over the land.
During the Jin Dynasty, with its formidable military might having already swallowed the Shu Kingdom, Emperor Wu of Jin set his sights on conquering the Wu Kingdom. He dispatched the general Yang Hu to station troops at Jiangling, secretly preparing for the campaign. Aware that Lu Kang, the Wu commander, was a master of military strategy, Yang Hu knew defeating Eastern Wu would not be achieved overnight. Thus, he outwardly adopted a policy of neighborly goodwill to win over the Wu people's hearts. Lu Kang, returning the favor, maintained a facade of peaceful coexistence with the Jin forces while secretly enforcing the strictest defenses.
However, Sun Hao, the ruler of Wu, overestimated his own strength. Instead of praising Lu Kang, he frequently rebuked him. Worse still, Sun Hao repeatedly sent troops to raid the borders of the Western Jin, exhausting the people and draining the kingdom's power.
Witnessing this, Lu Kang grew deeply concerned and submitted a memorial to the throne: "The court neglects agriculture and the strengthening of the state to ensure the people's well-being. Instead, it heeds misguided advice, engaging in reckless military campaigns that drain our treasury by the tens of thousands and exhaust our soldiers. By sapping our own strength, we risk total disaster if Jin launches a full-scale invasion."
However, Sun Hao refused to heed Lu Kang's loyal advice and went his own way. After Lu Kang's death, Emperor Wu of Jin realized that Eastern Wu had no capable generals left to lead its armies, so he immediately ordered an invasion. As a result, Eastern Wu, having exhausted its national strength through years of relentless warfare and with its soldiers and people weary of fighting, was unable to resist and was eventually conquered by Western Jin.
Later, the idiom "exhaust all military forces" came to describe using up all troops and being endlessly warlike.
Source: *Records of the Three Kingdoms*, "Biography of Lu Kang"
Meaning of the Idiom: Later, the Chinese idiom "穷兵黩武" came to describe using up all troops and being endlessly warlike.