Computers Cemetery, China

After Han's collapse, another period of disunion followed, including the highly chivalric period of the Three Kingdoms. Independent Chinese states of this period such as Wu opened diplomatic relations with Japan, introducing the Chinese writing system there. In 580 AD, China was reunited under the Sui. However, the Sui Dynasty was short-lived after a failure in the Goguryeo-Sui Wars (598–614) weakened it.
Under the succeeding Tang and Song dynasties, Chinese technology and culture reached its zenith. The Tang Empire was at its height of power until the middle of the 8th century, when the An Shi Rebellion destroyed the prosperity of the empire. The Song dynasty was the first government in world history to issue paper money and the first Chinese polity to establish a permanent standing navy. Between the 10th and 11th centuries, the population of China doubled in size. This growth came about through expanded rice cultivation in central and southern China, and the production of abundant food surpluses.
Within its borders, the Northern Song Dynasty had a population of some 100 million people. The Song Dynasty was a culturally rich period for philosophy and the arts. Landscape art and portrait painting were brought to new levels of maturity and complexity after the Tang Dynasty, and social elites gathered to view art, share their own, and trade precious artworks. Philosophers such as Cheng Yi and Chu Hsi reinvigorated Confucianism with new commentary, infused Buddhist ideals, and emphasized a new organization of classic texts that brought about the core doctrine of Neo-Confucianism.
In 1271, the Mongol leader and fifth Khagan of the Mongol Empire Kublai Khan established the Yuan Dynasty, with the last remnant of the Song Dynasty falling to the Yuan in 1279. Before the Mongol invasion, Chinese dynasties reportedly had approximately 120 million inhabitants; after the conquest was completed in 1279, the 1300 census reported roughly 60 million people. A peasant named Zhu Yuanzhang overthrew the Mongols in 1368 and founded the Ming Dynasty. Ming Dynasty thinkers such as Wang Yangming would further critique and expand Neo-Confucianism with ideas of individualism and innate morality that would have tremendous impact on later Japanese thought. Chosun Korea also became a nominal vassal state of Ming China and adopted much of its Neo-Confucian bureaucratic structure.