Brief introduction of important figures and their contributions in the unity and exchange between Chinese and foreign nationalities in Sui and Tang Dynasties.

Brief introduction of Sino-Japanese diplomacy in Sui and Tang Dynasties: Early folk exchanges between China and Japan began in the Qin Dynasty, and some immigrants moved to Japan. In the Han Dynasty, the local government of Kyushu, Japan, was made a vassal state, which was called official contacts between China and Japan. During the Three Kingdoms period, he still maintained diplomatic relations with the core regime of Kyushu and was named king of Japan. Jin Dynasty was a turning point in Sino-Japanese diplomatic relations. In the early days, the local government of Japan was also considered as the king of Japan. However, with the political changes in the Japanese archipelago, especially the large number of Japanese immigrants to Japan, the relationship between the two countries began to change. During the Jin Dynasty, Japan established a new regime centered on the Yamato region of Honshu, gradually replacing the former Japanese imperial regime in Kyushu, and the official exchanges with China were basically cut off in the middle and late Southern and Northern Dynasties. By the time the Sui Dynasty was unified, the new Japanese regime was no longer a primitive and slave tribe in the early Japanese archipelago, but gradually moved towards the rule of the feudal central government. It is no longer willing to maintain the old relationship with the Sui Dynasty in the mainland, preferring to be equal and independent, and the diplomatic relations between the two countries are also fluctuating. Emperor Wendi of Sui Dynasty dismissed the attitude of Japanese rulers calling themselves "heavenly brothers" and "taking Japan as their younger brother", thinking that it was against heaven and ordered them to make corrections. There were some frictions in the relationship between the two countries, so that the credentials of the Japanese rulers later claimed to be "the sunrise monarch led to the sunset monarch", which made Emperor Yangdi very dissatisfied and considered it unreasonable, and asked the foreign affairs department not to accept these rude credentials again. Pei sent a mission to Japan to ease relations between the two countries. Although Japanese rulers at that time, such as Emperor Tugu, Shoto Kutaishi and Suwomazi, were admirers of China culture, they were obviously unwilling to establish relations between the two countries according to the suzerain-vassal relationship in the Han and Jin Dynasties. They refused to accept the knighthood of the Sui Dynasty and no longer recognized the title of king of Japan, and the relationship between the two countries was temporarily suspended. In the early days of the Tang Dynasty, Japan never established official diplomatic relations with the Tang Dynasty. Obviously, since Baekje and Silla advocated to China and Japan at the same time, there are contradictions between China and Japan in establishing the status relationship between the two countries. It was not until 630 years after Emperor Taizong ascended the throne that Japan sent its first official mission. Emperor Taizong said that Japan can pay tribute from time to time, which is better than Baekje, Silla and other vassal countries, but Japan's attitude is still unclear. The following year, Emperor Taizong sent Gao Renbiao, a four-level official of NSW secretariat, to Japan, and his first diplomatic visit was suspended because of a etiquette dispute with the Japanese prince. This is obviously the result of disrespect for China, and it also reflects the change of Japanese attitude towards China. Opposition is also reflected in the policy of crowding out and suppressing mainland immigrants that began after the Dahua reform ten years ago, and it is not entirely Gao Ren's personal responsibility. Moreover, in the past two decades, Japan has not taken the initiative to repair relations between the two countries. Instead, in the process of modernization, it revised the China policy implemented during the Tugu emperor's era, which not only moved mainland immigrants to areas far away from the traffic lines and isolated them from the mainland, but also changed the seventeen constitutions and the concept of governing the country based on Chinese virtue, kindness, courtesy, wisdom and trust culture. Moreover, among the eight surnames, none of the major immigrant groups such as Qin, Han and Jin are among the top three. The reason why Emperor Taizong was worried about the situation in the East was also the development of Japanese political situation. Taking advantage of the contradiction between Silla and Japan, he formed an alliance with Silla in 648, separated Baekje from Japan, and presented Silla with the Book of Jin to support Silla's unification of the Korean Peninsula with the Datong River as the boundary. Facing the East Asia strategy launched by the Tang Dynasty, Japan felt pressure, and did not take the initiative to improve relations until Tang Gaozong ascended the throne. In 65 1 year, Japan condemned Silla's envoys for wearing Tang costumes, and sent two 100-member delegations to China for study in the following year, but formal diplomatic relations have not yet been established. With the gradual escalation of the Korean War, China and Japan are also moving towards the road of direct confrontation. The Tang Dynasty supported Silla against Baekje while uniting the Khitan against Korea, and Japan was not directly involved in the war for the time being. In 654, Tang Gaozong received gifts such as amber and agate, but Tang Gaozong asked the Japanese to send troops to Silla to prevent Goguryeo and Baekje from attacking Silla. The positions of these two countries are still at odds. In 660, Sue led an army to attack Baekje. At that time, the Japanese were too busy pacifying the shrimps in the north to help Baekje. After Tang Jun captured Baekje, the main force retreated. In 66 1 year, Japan sent Prince Baekje back to China to organize an anti-Tang movement. Liu Renyuan, Sima Facong and a few others who stayed in Baekje were surrounded by Baekje rebels and held on for nearly half a year. In 663, Liu, Sun and Du Shuang led troops to rescue Baekje, and the Japanese officially entered the war in public, mainly because Baekje had 10,000 people in Tang Jun and only 7,000 reinforcements. Japan sent tens of thousands of troops to join the Baekje Army, and the Japanese and Hundred Allied Forces, which were dominant in the Battle of Baicunjiang, were still defeated by the Tang and New Allied Forces. After Japan's defeat, it began to repair relations with the Tang Dynasty, and the Tang Dynasty also actively carried out peaceful diplomacy. The status of diplomatic envoys in the exchanges between the two countries has risen sharply. In 665 AD, Emperor Xuanzong of the Tang Dynasty sent diaspora doctors to Japan, and Wei Liu built a state official, with Guo Wuyuan as the third doctor. Among them, Liu is the second-class official of the Lord, much higher than the earliest secretariat. It can be seen that China sincerely hopes to restore peace with Japan. In 667, Tang Jun also gained an advantage in the Koguryo battlefield. This year, Sima Facong, also the top scholar, was sent to Japan. Sino-Japanese diplomatic relations are basically on the right track, and China has not made Japan a vassal and maintained equal relations. After Japan's massive attack on Silla was repelled in 73 1 year, the fierce war in East Asia basically ended and the long-term peace situation was restored. From then until the end of the Tang Dynasty, China and Japan exchanged envoys, especially Japan sent envoys of the Tang Dynasty to study and work in China many times. For more than 200 years, the cultural, economic and political exchanges between China and Japan have developed peacefully, which has greatly enhanced the friendship between the Chinese and Japanese peoples and played a role in historical progress.