What is the bottom line between the closed window and the moon?

The bottom line is: throw stones to break through the underwater sky.

This couplet comes from Su Xiaomei, Su Dongpo's sister in Song Dynasty, who embarrassed the groom Qin Guan on their wedding night. They are right, the whole couplet:

Push the moon out of the window behind closed doors, throw stones to break the underwater sky.

It means: the moon is closed in front of the window, and the stone is thrown in the pool.

On the surface, it means to close the window, but from the inside, it means to shut the moon in front of the window in the sky, shut the door and not allow to enter the house. The moon is a metaphor for Qin Shaoyou, which means that Qin Shaoyou is shut out by the night sky.

On the surface, "throwing stones to break the underwater sky" means throwing stones to break the sky in the pool, and I washed it away. The moral is that you push the moon out of the window and lock it in the night sky. I washed it away by throwing stones. As soon as it opened, I (the moon) could naturally enter the house.

Extended data:

Source allusion:

Qin Guan, a poet in the Song Dynasty, was gifted. He heard that Su Dongpo's sister, Su Xiaomei, was not only beautiful in appearance, but also able to write poems and good words, and had long admired her. Later, Qin Guan and Su Xiaomei tied the knot and became a much-told story in the literary world.

It is said that on their wedding night, in order to find out Qin Guan's literary talent, Su Xiaomei turned him away and asked him to answer three questions before entering the wedding. Qin Guan quickly answered the first two questions, and the third question was couplets.

When Su Xiaomei stood at the window of the house, he opened the window and saw a bright moon hanging in the sky. So, the first part was published: "Close the door and launch the window and the moon."

Qin Shaoyou thought for a long time, but he didn't come up with the bottom line. Su Dongpo saw it. He was worried about his brother-in-law, but it didn't help. Looking at the pond in the moonlight, he suddenly had a brainwave, picked up a stone and threw it into the water. After Qin Shaoyou saw it, he immediately made a couplet: "Throw a stone and boil water."

Baidu Encyclopedia-Su Xiaomei