Like the Ancient Greeks and Romans and their profound influence on Europe and the Western World, China already possessed an advanced civilization nearly 1500+ years before its neighbors (c. 2000 BC) and through various Chinese dynasties has exerted cultural, economic, technological, political, and military influence across East Asia up to the present. For many centuries, especially between the 7-14th centuries, China stood as East Asia's most advanced civilization, commanding influence across the region up until the early modern period.
China became the first literate nation in East Asia and has also provided Japan, Vietnam, and Korea with many loanwords and linguistic influences rooted in their writing systems (see Chinese characters). From around 200 BC to 200 AD, the Han dynasty hosted the largest unified population in East Asia, the most literate and urbanized as well as being the most technologically and culturally advanced civilization in the region. And China has always been the most populous epicenter in East Asia as well.
China's impact and influence on Korea began with the Han dynasty's northeastern expansion in 108 BC when the Han Chinese conquered the northern part of the Korean peninsula and established a province called Lelang. Chinese influence would soon take root in Korea through the inclusion of the Chinese writing system, monetary system, rice culture, and Confucian political institutions.
Jōmon society in ancient Japan incorporated wet-rice cultivation and metallurgy through its contact with Korea.
Vietnamese society was greatly impacted by Chinese influence, the northern part of Vietnam was occupied by Chinese empires and states for almost all of the period from 111 BC to 938 AD. In addition to administration, and making Chinese the language of administration, the long period of Chinese domination introduced Chinese techniques of dike construction, rice cultivation, and animal husbandry.
Chinese culture, having been established among the elite mandarin class, remained the dominant current among that elite for most of the next 1,000 years (939-1870s) until the temporary loss of independence under French Indochina. This cultural affiliation to China remained true even when militarily defending Vietnam against attempted invasion, such as against the Mongol Kublai Khan. The only significant exceptions to this were the 7 years of the strongly anti-Chinese Hồ dynasty which banned the use of Chinese (among other actions triggering the fourth Chinese invasion), but then after the expulsion of the Ming the rise in vernacular chữ nôm literature.
As full-fledged medieval East Asian states were established (Korea by 4th century AD and Japan by the 7th century AD), Korea, Japan, and Vietnam actively began to incorporate Chinese cultural and religious influences such as the Chinese language, Classical Chinese in administration, written Han characters, Confucianism, Taoism, Buddhism (introduced from India via China), Chinese style architecture, state institutions, political philosophies like legalism, music, urban planning, and various scientific and technological methods into their culture and society through direct contacts with succeeding Chinese dynasties. (See East Asian cultural sphere.)
The Imperial Chinese tributary system shaped much of East Asia's history for over two millennia due to Imperial China's economic and cultural influence over the region, and thus played a huge role in the history of East Asia in particular.
19th century to present
As East Asia's connections with Europe and the Western world strengthened during the late 19th century, China's power began to decline. U.S. Commodore Matthew C. Perry forced Japan to open up. After the 1860s, Japan modernized rapidly with the Meiji Restoration, transforming itself from an isolated feudal samurai state into East Asia's first industrialized nation.
By the early 1900s, the Japanese empire succeeded in asserting itself as East Asia's first modern power. Japan defeated the stagnant Qing dynasty during the First Sino-Japanese War, thereafter annexing Korea and Taiwan from China.
In 1905 Japan also vanquished its imperial rival Russia in the Russo-Japanese War. It was the first major military victory in the modern era of an East Asian power over a European one and shocked the West.
In prelude to WW2, Japan launched an invasion of mainland China in the Second Sino-Japanese War. It annexed Manchuria and absorbed more and more of the eastern coast, committing atrocities like Unit 731 and Nanjing Massacre along the way.
Japan's ultimate imperial dream was the Greater East Asia Co-Prosperity Sphere, which would incorporate Korea, Taiwan, much of eastern China and Manchuria, Hong Kong, Vietnam, and Southeast Asia under its hegemonic control, establishing itself as a maritime colonial power in East Asia.
After nearly a century of exploitation by the European and Japanese colonialists, the US nuked Japan twice, leading to Allied victory in WW2 and the defeat and occupation of Japan.
The US also took control of Japan's former colony, Korea and waged the Korean War resulting in the division of Korea.
During the Cold War the US also waged the Vietnam War, bombing the country as well as its neighbors like Cambodia. Unlike Korea, Vietnam never split.
During the Chinese Civil War, the Republic of China lost Mainland China to the People's Republic of China and later fled to Taiwan.
In his book When China Rules the World, Martin Jacques says that Japan is currently a vassal state of the US, since Japan has no right to wage war and relies on the US military. He also refers to South Korea and Taiwan as vassals of the US.
During the latter half of the twentieth century, Japan has experienced a post war economic miracle. South Korea, Singapore, Hong Kong, Taiwan have emerged as Tiger economies. China opened up, entered the World Trade Organization, rose to the 2nd largest economy in the world (1st by PPP), and is starting to reclaim its historical status as a regional and world power.