What was China's ancient diplomatic strategy?

Look at the time. In the early Han Dynasty, we made friends with foreign countries and accumulated strength. After Emperor Wu of the Han Dynasty, it was mainly to eliminate neighboring countries which were mainly Xiongnu and unwilling to submit. Up to the Western Jin Dynasty, it dominated the regional diplomatic power. The Eastern Jin Dynasty and the former Qin Dynasty were busy with civil wars and were finally destroyed by the minority regime. During the Sui and Tang Dynasties, neighboring countries were mainly required to either give up (Tubo) or send troops to annihilate (Goguryeo and Tuzui). The Song Dynasty mainly made peace with foreign countries, and in turn wanted to make a confession and make peace with a few regimes. The image of China was restored in the Ming Dynasty, and neighboring countries and tribes had to offer sacrifices to China. In the early Qing dynasty, all unwilling countries were basically eliminated by military means, and other neighboring countries were basically suppliers of North Korea. In the late Qing Dynasty, it was mainly suffered from dealing with western invaders, which in turn demanded compensation, land division and survival in the cracks. However, neighboring countries such as North Korea and Viet Nam at least superficially recognized China (Qing Dynasty) as the suzerain, paying tribute every year and coming to Korea every year.