When Mencius arrived in the state of Qi, King Xuan of Qi asked him about the strategies of Duke Huan of Qi and Duke Wen of Jin, the great hegemons of the Spring and Autumn period. Instead of answering directly, Mencius launched into a discourse on how moral virtue could unite the world under heaven.
King Xuan of Qi asked in confusion, "What kind of virtue can unite the world?" Mencius replied, "When the people's lives are stable, the world can be united. No force can resist that." The king pressed, "Can a ruler like me bring stability to the people?" Mencius answered, "Yes." "How do you know I can?"
Mencius said to King Xuan of Qi, "You couldn't bear to see an ox trembling in fear, so you ordered a sheep to be sacrificed instead. This compassionate heart is enough to unite the entire realm. The people think you are stingy, but I know it is because you cannot bear the suffering. However, you should not be surprised that the people call you stingy—how could they understand that your true intention stems from benevolence? In truth, when it comes to pitying an innocent creature about to be slaughtered, what difference is there between killing an ox and killing a sheep?"
Mencius continued, "If someone reported to Your Majesty, 'I am strong enough to lift three thousand jin, yet cannot lift a single feather; I can see the tip of an autumn hair clearly, yet cannot see a cartload of firewood before me.' Would you believe this?"
"Of course not." King Xuan of Qi replied immediately.
Xu Peng replied, "Your kindness benefits animals but not the people—why is that? The truth is, failing to lift a single feather comes from not using your strength; not seeing a cartload of firewood comes from not using your eyes. The people lack peace because you refuse to grant them favor. So, your failure to unite the world through virtue is a matter of unwillingness, not inability."
"The idiom 'Ming Cha Qiu Hao' means sharp-eyed enough to see the fine down of birds and beasts in autumn. Originally it implied seeing only small details while missing the big picture. Now it generally describes someone so perceptive that they can discern even the tiniest matters with perfect clarity."
Source: *Mencius*, Chapter "King Hui of Liang I"
Meaning of the Idiom: Later, the Chinese idiom "明察秋毫" came to describe how someone is so perceptive that they can discern even the tiniest matters with perfect clarity.