What is the historical background of "having an answer"?

It means that when drawing bamboo, you should have the image of bamboo in your mind. Don't think about it, draw it and make it up, which means that you have an idea before you do something, and it also means that you are skilled and sure.

In the Northern Song Dynasty, there was a famous painter named Wen Tong, who was a master of bamboo painting at that time.

In order to draw bamboo well, Wen Tong drills in the bamboo forest all the year round, no matter spring, summer, autumn and winter, whether it is windy or rainy. In dog days, the sun burns the earth like fire. However, Wen Tong still ran to the side of the bamboo forest facing away from the sun, stood in the scorching sun and observed the changes of bamboo with rapt attention. He measured the length of the bamboo joint with his fingers for a while, and then recorded how dense the bamboo leaves were. Sweat soaked his clothes and his face was sweating, but he seemed fine.

Once, a strong wind blew in the sky. Then, there was lightning and thunder. Seeing that the storm was coming, people ran home. Just then, Wen Tong, who was sitting at home, grabbed a straw hat in a hurry, buckled it on his head and ran straight to the bamboo forest on the mountain. Hardly had he stepped out of the gate when the heavy rain began to splash water with the washbasin.

Wen Tong is bent on seeing bamboo in the storm, but he can't slip in the rain! He lifted his clothes, climbed the hillside and ran to the bamboo forest. Out of breath, he ran into the bamboo forest and looked at the bamboo unblinkingly without wiping the rain on his face. I saw bamboo in the wind and rain, bent down and nodded, swaying. Wen Tong carefully kept in mind the posture of bamboo being hit by wind and rain.

Because Wen Tong has carefully observed and studied bamboo for many years, what changes have taken place in the shape of bamboo in spring, summer, autumn and winter? What is the difference between the color and posture of bamboo in rainy and snowy days? What's the difference between bamboo in strong sunlight and bamboo in bright moonlight? He knows exactly what different bamboos look like. So when you draw bamboo, you don't need to sketch at all.

A man named Joe Bu Zhi praised Wentong and said, "Wentong already has a plan." The bamboo painted by Wen Tong is famous far and wide, and many people come to ask for paintings every day.

Wen Neng grows all kinds of bamboo in front of and behind his house. No matter spring, summer, autumn and winter, rain or shine, he often goes to the bamboo forest to observe the growth and change of bamboo, figure out the length and thickness of bamboo branches, the shape and color of leaves, and return to his study with new insights and draw his impressions on paper. Various images of bamboo are deeply imprinted in his mind. Therefore, every time he draws bamboo, it seems very calm, and the bamboo he draws is vivid and lifelike.

When people praised his paintings, he always said modestly, "I just painted the mature bamboo in my heart."