What does the idiom "one leaf is blind" mean?

Pronunciation of idioms

Idiom definition: the eyes are blocked by a leaf, which means that you can't see the whole picture of things.

The origin of the idiom: Mao Zedong's "On protracted war": "A leaf can't see Mount Tai, and it's self-righteous."

This idiom is often used to describe a person who is blinded by the smallest thing in front of him and can't see the whole and essence of things. This is from the ancient book "A leaf can't see Mount Tai; Two earplugs and beans don't smell thunder.

When later generations explained this, Laughing Forest written by Han Danchun in the Three Kingdoms period was the most interesting. He told a joke that "one leaf can't see Mount Tai", saying that there was a poor scholar in Chu who wanted to make a fortune by crooked ways. The scholar remembers reading the story of mantis catching cicada when he was studying. The mantis hid behind the leaves and succeeded in one fell swoop.

So he went to look for the leaves that covered the mantis. He really found a leaf hidden behind the mantis. He picked it off at once, but accidentally slipped his hand. The leaf fell into a pile of fallen leaves. The scholar put all the leaves in a laundry basket and took them home to block his eyes for an experiment. He asked his wife, "Can you see me?"

At first, his wife truthfully replied that it was visible, but poor scholars took pains to test it with a laundry list of leaves. His wife suddenly lied to him and said, "This leaf hides you, so I can't see." If the poor scholar gets the treasure, he thinks it is a hidden mantis leaf. He took the leaves to the market to block his eyes and took the goods from the vendors. Of course, he was immediately caught by the businessman and handed over to the county magistrate. Scold him is really "a leaf can't see Mount Tai!" Give him a good beating and send him home.

A joke is a joke after all. However, it is very appropriate to use exaggerated jokes to compare the similar actions of some people in real life and satirize the whole without looking at it.