Mainly because Wang Xizhi practiced very hard since he was a child. He had many years of experience in calligraphy before drinking, so he could write well even when he was drunk. The story in "Preface to the Lanting Collection" left an impression on the public that wine can promote the improvement of one's artistic level. Therefore, in later generations, even in modern times, many artists will drink a little alcohol when creating. It is like a ritual. They believe that exposure to some alcohol can unconsciously improve their level. But in fact, after most people drink, their artistic level cannot be greatly improved. Even because they are drunk, their artistic works are worse than before they drank.
But why was Wang Xizhi able to write the preface to the Lanting Collection after drinking? It was mainly because Wang Xizhi himself was very diligent. According to historical records, Wang Xizhi, who was born in a family of officials, did not develop the bad habits of arrogance and extravagance, but instead embarked on the path of calligraphy. He has been interested in calligraphy since he was a child. Before he could read, he would often scribble and draw on the sand, showing great interest. After his father saw this, he immediately sent him to a famous calligrapher so that he could receive the best training.
With the training of famous calligraphers, Wang Xizhi's calligraphy was already well-known in the local area when he was only 10 years old. In the story of Wang Xizhi, it is also recorded that because he was so obsessed with practicing calligraphy, he accidentally dipped the cake in ink and ate it together. This also illustrates Wang Xizhi's dedication to practicing calligraphy. In addition to the calligraphy skills taught by the teacher in class, he also worked hard to practice various calligraphy skills of the ancients. He practiced calligraphy in the house all year round, so he was able to write the masterpiece "Preface to the Lanting Collection" after he got drunk in Prince Teng's Pavilion.
So it’s not that Wang Xizhi’s level suddenly improved after drinking. In fact, he was already a well-known local calligrapher before that. Being drunk just helped him to show his best state. Therefore, if future generations want to be as successful as Wang Xizhi, diligent practice is essential.