Japanese belongs to the cohesive language family. At first, Japan didn't have its own writing. During the Sui Dynasty, China was powerful, and the Japanese sent envoys to the Sui Dynasty, as well as some monks studying abroad. They brought Chinese characters to Japan and took root. Chinese has become the imperial language of the Japanese court, and only royal and aristocratic officials can learn and use it. In the Tang Dynasty, he continued to send envoys to the Tang Dynasty. At this time, the Japanese also created their own characters Hiragana and Katakana according to China's characters. Hiragana comes from China cursive script, and Katakana comes from the radical of China regular script. At this time, Japanese has several pronunciations: five tones, Tang tones and Chinese tones. Therefore, some words in modern Japanese have more pronunciations than excellent varieties. This is caused by the introduction of different pronunciations in Japanese-Chinese cultural exchanges. In Heian period, Chinese characters were still the main writing form of official documents in the imperial court, but the female officials in the palace used Hiragana because of the cultural influence, and Hiragana at this time was called "female hand". At this time, women's literature was very developed, and several excellent women writers were produced. Due to the weakness of China in the late Tang Dynasty, Sugawara no michizane abolished the envoy to Tang Dynasty. Japan's prosperity from early sinology to sinology in Japan is called "the dark period of sinology". Chinese characters began to decline. Hiragana has gradually become the main language used in Japan. After hundreds of years of Wu family feudalism, Meiji Restoration. Many scientific terms imported from Europe and America are expressed by katakana. With the development of science and politics, Japan began to create some unique names with Chinese characters, and also created some "national characters". Many words about politics and physical science in China are imported from Japan, but they are actually foreign words.