Definition: The original meaning is to have no knowledge of the beginning, development, or outcome of something, but now it is used to indicate that there is no knowledge of the actual situation.

Allusion: In 468 BC, Xunyao of Jin led his troops to attack Zheng. Zheng was a powerful country in the early Spring and Autumn Period, but later weakened and became a weak vassal state. The king of Zheng could not resist the attack of the Jin army, so he sent a doctor to Qi to ask for help.

After arriving in the state of Qi like a son, he explained to the monarch of Qi that if the state of Jin annexed Zheng, it would threaten the state of Qi, and asked the state of Qi to send troops to rescue Zheng. The monarch of Qi felt that the son's words were reasonable, so he sent doctor Chen Chengzi to lead the army to the rescue. When Chen Chengzi led the army to the bank of the Zishui River, it was raining heavily, and the soldiers were unwilling to cross the river in the rain. At this time, Zheng's guide was very clear that if the Qi army did not hurry up, the capital of Zheng State might be in danger. So he urged Chen Chengzi to cross the river quickly. Chen Chengzi also knew that the situation was urgent, so he ordered him to cross the river. Chen Chengzi, wearing a canopy and leaning on the soldiers, stood anxiously on the hillside and commanded the Qi army to cross the river. When the war horse saw the river water scooping up, he screamed in fright. He used a whip to force them to cross the river. After some hard work, the Qi army safely crossed the Zishui River and was ready to fight the Jin army.

The commander of the Jin army, Xun Yao, was surprised when he saw the Qi army coming to save Zheng, because he did not expect that Qi would send troops to fight Jin. He was a little scared when he saw the sharp appearance of the Qi army, so he said to the generals on the left and right: "Their troops are very neatly arranged, I am afraid we will not be able to defeat them. Let's withdraw our troops." As Xunyao ordered the withdrawal of the army, he sent a messenger to the Qi army camp to visit Chen Chengzi, hoping that the messenger would drive a wedge between Chen Chengzi and Zheng. Unexpectedly, Chen Chengzi did not believe what the messenger said and drove him back. After the emissary of Qi left, a man named Xun Yin reported to Chen Chengzi: "A man from the Jin army told me that the Jin army plans to send a thousand chariots to attack our camp gate and destroy all the Qi army." Chen Chengzi listened and scolded him: "Before leaving, the monarch ordered me: 'Don't chase after sporadic soldiers, and don't be afraid of large numbers of people.' Even if the Jin army dispatched more than a thousand chariots, I couldn't avoid fighting. You just said that you would strengthen the enemy's prestige and destroy your own ambition. After returning to China, I will report your words to the monarch." Xun Yin knew he had made a mistake, so he said with emotion: "The plan of a gentleman is also to use it in the beginning and the end, and the last one is to enter. Now that I don't know about it, isn't it difficult for me to enter? "This means: Mingren plans a thing, and takes into account the beginning, development, and result of the thing, and then reports it to the police. I don't know these three aspects and report them to the police. How can I not hit a wall? A few days later, the Jin army withdrew, and Chen Chengzi also led the army back to China.