
There's a reason why that 20% of the Earth's population is Han Chinese and that the People's Republic of China is among the most monoethnic nations on Earth. The Chinese people are a warrior people and due to their success they've been around so long and are all over the world. Compared to the Jews of whom they seem to be dying out most of the world except for Europe, North America and Israel. Ask the last Jew of Kabul or the last hundred or so Jews left in Yemen. In contrast to that, there's Chinese people everywhere and this trend has been noticed in African countries such as Sudan, Angola, Zambia where the Chinese government is making deals to secure mineral riches under the Earth. All the power to them, after all it's their job to maintain Chinese Civilization much like their predecessors.
The peoples who today make up China have always been fighting each other and there's always been someone to record them killing each other apparently. At least since the Xia dynasty which introduced feudalism in China around 2200 BC. Much like in Europe, vassal holders would fight each other for fiefs. The Shang were cool too, they created the first bronzes allowing the Chinese to kill each other with bronze spears, swords and they created the first Chinese writing (albeit on tortoise shells). The Chief of the West's dynasty, the Zhou Dynasty was trashed by northern barbarians and soon China descended into a Warring States Period...
The Zhou split up to hundreds of Chinese states, a ripe atmosphere for war in any case but the tactics they used were a little iffy. In 638 BC the Duke of Sung refused to attack an army moving across the river, 2000 years later Mao was reported to have said "I am not the Duke of Sung". Other strange things happened like relieving the siege of starving cities because of cannibalism. At least other states like Chin or Qin actually new how to conduct warfare. Other states too like Wu who had hired Sun Tzu to command his armies and soon by 450 BC several states survived: Qin, Chu, Zhao, Qi, Wei, Han and Yan. During this time Taoism developed, probably a response to the chaotic nature of Chinese politics. Confucius also came up to, as a method to restoring traditional Chinese values to a society shaped by warfare. Along with Mencius, Hsun-Tzu and Mo-Tzu.
Eventually, Qin conquered all and Shi Huang Ti became the first Emperor of China in 221 BC, ruling more than any before him. Chinese bureaucracy was created to end feudalism. Instead of giving land to great generals etc, give them titles and pensions as his lawgiver Li Ssu suggested. It was the right suggestion in the long-run. Some not so bright ideas were making hundreds of thousands of workers toil on his tomb, sending thousands to look for the immortal islands and building a Great Wall in which a warlord could easily just go around it (like Mr Jenghis Khan did) but it didn't only keep barbarians like the Hsiung Nu out.. it kept the Chinese in. Another bad thing he did was burning every history book because some Confucian scholar pissed him off about not being given land. Imagine all the knowledge we've lost!
After his death, his Empire collapsed and various warlords fought it out in vicious battles and massacres like burning of Hsien-Yang, the Imperial capital. Eventually, a commoner named Liu Pang won out after having his rival murdered and hacked to pieces in a marsh somewhere in Southern China. This is where the Han Chinese people move south on mass. The Han Dynasty embraced this region and conquered it's non-Han peoples (who do still exist today but in marginal numbers). However the Northern peoples were not easily contained and the cost of that war ruined the Empire. A rebel named Wang Mang won control of the Empire around 9 AD and he made the financial situation worse by taking all the gold out of circulation thus making China unable to trade with the outside world.
It got worse later on when 161 AD when an epidemic killed 3 out of every 1o people which caused one of the major pitfalls of Chinese rule to occur - whenever something shitty happens the Chinese people turn to religion. The other way how Chinese rule collapses is when a ruling dynasty becomes corrupt and inept and warlord/often with the help of a foreigner replaces the ruling dynasty. This time, a mystic named Chang Chio created a movement called the "Way of Peace" and grew and army called the Yellow Turbans. The Imperial armies were intimidated at first but they eventually overcame the Yellow Turbans with the help of private armies from warlords. A succession crisis after the death of the ruling Emperor led to the Romance of the Three Kingdoms and the Battle of Red Bluff which created a North/South division of China. It got way worse when Tibetans, Huns and other foreigners invaded China and the Toba people pushed the Chinese far South around 386 AD forcing them to absorb, kill or displace these southern peoples who farmed rice and lived off pork. This disperal of peoples is still present on the border of China and South-East Asia where small pockets of Austro-Asian and Hmong-Mien speakers live.
The Toba people ruled and brought in Buddhism, among the two old faiths Confucianism and Taoism. Somehow, the Chinese people managed to embrace all three along with the traditional Chinese folk religions. Unlike its Western counterpart, it didn't have to kill Christians until much, much later. Soon the Sui dynasty was to rule.
The Chinese people had been fighting for over 4000 years in organized warfare and united under various warlords and fought off foreign invaders too at the cost of millions. As in the past, in the next part of this wonderful episode of the Han Chinese people millions more would die at the hands of Mongols, Manchus, Europeans, Japanese, Koreans and of course Chinese people. After all, nobody does it better than the Chinese.

