In 200 AD, the warlord Cao Cao launched a campaign against his rival Yuan Shao and dispatched his advisor Wei Ji on a diplomatic mission to Yi Province to forge an alliance with its governor, Liu Zhang.
When Wei Ji reached Chang'an, he found the roads blocked and was forced to remain in Guanzhong.
The Guanzhong region, once a land of plenty, had seen hundreds of thousands flee during years of war. Now, with peace restored, people streamed back to their old homes. Local generals, seizing the opportunity, recruited these jobless returnees as private soldiers to bolster their own power.
Wei Ji, a perceptive official, sensed that the growing power of local factions in Guanzhong was threatening the central authority of the Cao regime. He wrote a letter to Cao Cao's chief strategist, Xun Yu, proposing, "We should send the Colonel of the Capital Districts to strengthen control over Guanzhong and weaken these regional forces." This strategic advice aimed to consolidate power and prevent the fragmentation of the state.
Cao Cao adopted Wei Ji's advice, and soon the situation in Guanzhong stabilized.
In 227 AD, Emperor Ming of Wei, Cao Rui, ascended the throne. Known for his cruelty and extravagance, he launched massive construction projects, built lavish palaces, and seized farmland to create deer parks—anyone who killed a single deer would be executed.
Emperor Cao Rui of the Wei Dynasty indulged in extreme luxury, forcing his people into endless years of hard labor, which left the fields barren and the state treasury empty.
Wei Ji, deeply troubled by the state of affairs, submitted a memorial to Emperor Ming of Wei, warning, "The realm is divided, the nation not yet unified. For a thousand li, there are no signs of human life, and the people are suffering beyond measure. If Your Majesty continues to overlook this, the state will decline and never revive." He concluded, "The urgent task now is for ruler and ministers alike to pool their strategies, audit the treasury, and ensure that expenditures match income."
This means that the most urgent task now is for the ruler and ministers to join forces in devising strategies and precisely calculating the treasury's financial resources, determining the limits of expenditure based on the state of income.
However, Cao Rui ignored Wei Ji's advice and continued indulging his whims. The Cao Wei regime grew increasingly corrupt, eventually falling to the Sima family. In 265 AD, Sima Yi's grandson, Sima Yan, usurped the throne and established the Jin Dynasty, unifying the Three Kingdoms.
Later, people used the idiom "live within your means" to refer to determining spending limits based on income.
Source: *Records of the Three Kingdoms*, "Biography of Wei Ji"
Meaning of the Idiom: Later, the Chinese idiom "量入为出" came to describe how determining spending limits based on income.