During the Warring States period, King Hui of Qin planned to attack the resource-rich state of Shu, but the treacherous mountain roads into Shu forced his army to turn back midway.
Qin Hui Wang summoned his close advisors to discuss how to conquer the Shu state. Someone suggested that the Shu marquis was greedy, so bribing him with gold would allow a clever strategy. The king repeatedly praised the idea and ordered stonemasons to carve a large jade into a stone ox, hollow out its body, stuff it with gold and silk, calling it "ox-dung gold," and prepared to send it to the Shu marquis.
Soon, word reached the Shu kingdom. The Marquis of Shu was overjoyed and, ignoring the warnings of his veteran ministers, received the Qin envoy. The Qin envoy expressed to the Marquis of Shu that the King of Qin wished to forge eternal friendship with Shu. As a token of goodwill, he offered to present the gold-producing stone oxen.
The Marquis of Shu was overjoyed and eagerly asked when the stone oxen would arrive. The Qin envoy replied that the mountain paths into Shu were steep and treacherous, and it would take at least a year to transport them. Blinded by his desire for the stone oxen, the Marquis ignored his ministers' urgent warnings and ordered the entire kingdom's laborers to carve a road through the mountains.
When the King of Qin learned that the Marquis of Shu had indeed fallen for the trap, mobilizing tens of thousands of laborers to carve a road through the mountains, he immediately gathered his elite troops and, under the pretext of transporting the stone oxen, marched straight into the kingdom of Shu.
After months of labor, laborers from Shu finally completed the road to Shu. When the forces of Qin and Shu met, the Marquis of Shu sent men to move the stone oxen, while the Qin army, under the guise of escorting them, followed close behind into Shu.
The Marquis of Shu was overjoyed when the stone oxen arrived, personally leading his ministers outside the capital to welcome them. But when the Qin army saw that the marquis had fallen for the trick, they immediately raised their weapons and conquered the kingdom of Shu.
Thus, King Hui of Qin used the clever ruse of stone oxen to annex the Shu state. Later generations mocked the Marquis of Shu, saying, "For coveting petty gains, he ended up losing great advantages." Subsequently, people used the idiom "Penny Wise, Pound Foolish" to describe suffering major losses due to greed for small profits.
Source: *Lüshi Chunqiu*, Chapter "Quan Xun"
Meaning of the Idiom: Later, the Chinese idiom "贪小失大" came to describe how suffering major losses due to greed for small profits.