There is a sense of seriousness in the Japanese national character, which most people in China do not have. It took them a long time to learn about China. At first, they admired China culture, but in the Tang Dynasty, they began to learn from us on a large scale. When they were in the Sui Dynasty in Yang Di, they were still very conceited, and they were called the Eastern and Western Emperors together with Emperor Yangdi. Only when they knew that they were defeated by Liu in the Battle of Baijiangkou in Korea did they know our ability, and then they kept sending envoys of the Tang Dynasty to China to study. However, with the collapse of the Southern Song Dynasty, they thought that the real Central Plains culture had declined in China, but it was preserved there. At this time, they gradually began to despise China and even began to covet us. From the late Yuan Dynasty to the Ming Dynasty, the Japanese harassed the coastal areas of China. During the Wanli period of the Ming Dynasty, they even tried to invade China with Korea as a springboard. Later, because they regarded China as their opponent, they learned more about China in order to invade China better.