Manchuria, also known as Northeast China (but never Manzhouguo/Manchukuo, unless you're discussing that particular country academically), is usually composed of the provinces of Jilin, Liaoning, and Heilongjiang, with the eastern part of Inner Mongolia sometimes included. "Manchuria" was a name used by the Japanese and exported to the West, having never been used by the Han Chinese or Manchus themselves. Calling this region Manchuria in the PRC causes a Berserk Button among patriotic ethnic Chinese as it remains an awful reminder to Japan's imperialist actions in the region. The Manchus themselves also detest the name "Manchuria" because of the connections with Japan (who unsurprisingly also treated them horribly) and they have traditionally referred to the region as "dergi ilan golo" (Three Eastern Provinces) instead.
Manchuria is a region in China that, despite today being a relatively obscure region, played quite a large role in World History. This is the homeland of the Manchus that would create the last Chinese dynasty; the Turkic Peoples originated from here; this is also a bone of contention for the First Sino-Japanese War and Russo-Japanese War; this is also again a bone of contention for China and Japan in the Second Sino-Japanese War and later World War II; and lastly, this is the decisive battlefield for the middle phase of the 1946-50 Chinese Civil War. Why did such a small region become so important?
One great reason is a an abundance of the same seams and coal which run through North Korea (and to a lesser extent, South Korea), and reasonably fertile soils combined with a six-month planting season; Manchuria is currently home to some 109 million people, a rather impressive number for a region so close to Siberia. Another is geography: the port of Dalian does not freeze over in the winter. If Russia were able to control it then it could could sell those resources and food to China/Japan and have year-round access to the Pacific (its major Pacific port, Vladivostok, freezes during winter). If Japan controlled it, it would be more economically self-reliant and could sustain the expansion of its population and industrial base. China valued it as well, since the mines and railways put in place by Russia and Japan helped the communist regime's early economic growth once they were outfitted with machinery.
A third reason is that Manchuria was the ethnogenesis of the last great Chinese Dynasty, the Qing. It was founded by a Tungusic people called the Manchus, formerly called the Jurchen. For years after the conquest, the Manchus tried to separate it from the rest of China by building the so-called Willow Palisade, a network of willow trees forming along the border between China and Manchuria, in case the Han managed to overthrow their Manchu rulers - they would have their homelands to escape to. The Manchus, in time, got assimilated into Chinese society, and allowed the Chinese to settle there in the 19th century to prevent Tsarist Russia (already having snapped Outer Manchuria) from taking more Manchurian territory. It was called the Chuang Guandong movement, akin to the Westward Movement of the United States. As a result, the Chinese are the majority of Manchuria today, and it is now simply called Northeast China. The Manchus sinicized very quickly, and most of it was their own doing. The "Manchu" identity was very newly formed, being a mixture of different Tungusic and some other Siberian people under the rule of the Jianzhou Jurchen. The Manchus being a vassal to the former Chinese Ming Dynasty had already adopted many aspects of Chinese culture and were enamoured with it, the Sinophilic Manchu continued with aspirations to be culturally Chinese even when they ruled China itself. The Manchus were the first to suggest that people could still be "Chinese" without being ethnically Han. The Manchu married frequently with Han and Mongols thinking it would be boost their population but instead their offspring would end up being influenced by Chinese or Mongolian culture which diluted their own customs.
Then came the warlord period in China, and Manchuria was run as a fiefdom by Zhang Zuolin, who was Japanese-friendly. When he tried to reduce Japanese influence, the Japanese were not amused. In 1928, his train was blown up. Then the 1931 Manchurian Incident also occurred, the Japanese claiming that the Chinese authorities there were harassing the Japanese-owned South Manchurian Railway and even blew it up. The Chinese said that the explosion was a False Flag Operation by Japan, and there are credible evidence that supports the latter. The Japanese eventually prevailed and Pu Yi, the last emperor of China, was installed as the new head of state and later Emperor of Manchukuo. It was supposed to be independent; with the titular Manchu ethnic group, the Han Chinese majority, the Koreans, the Mongols, and Japanese working in harmony. Of course, Japan ran it as a Puppet State, with Japanese officials getting the final power in matters. Unit 731 also was founded in Manchuria.
The reaction was mixed. The Han Chinese majority saw Manchuria as part of China and many of them resisted by both passive and active means. The Manchus were somewhat more divided; some part took the former position, others saw it as a last chance to have their own homeland, knowing that they were almost completely assimilated by China, never mind that the Japanese authorities were much worse.
In the final days of World War II the Soviets invaded Manchuria, arrested Pu Yi, and set about dismantling and shipping back all the heavy machinery and industrial plant they could find to the Soviet Union - right down to the office furniture and windows... and power-plants, causing tens of thousands to die of cold in the winter of 1945-6. Meanwhile, they negotiated the Sino-Soviet Treaty of Friendship, Alliance, and Mutual Assistance which entitled them to the use of Dalian and to operate Sino-Soviet joint-stock companies in Xinjiang and Manchuria for several years (before they would be given over to China). Rather than destroying the Japanese armaments they captured, they let the Chinese Communists have them and trained them in their use; this was done to weaken the Kuomintang and thereby delay the (inevitable) Rise of China. They also let Communists take over the Manchurian countryside. Unfortunately, Josef Stalin miscalculated: this not only enabled the Communist to begin fighting and winning major battles against the KMT, but when the Soviets withdrew it allowed them to encircle the KMT's best forces in the Manchurian cities and win a decisive victory which swung the balance of power in their favour - and ultimately led to their victory.
Stalin let Kim Il-Sung start The Korean War because he would gain access to the warmwater ports of Busan or Incheon in the event of North Korean victory (which would occur without American intervention), and he would be able to prolong the unequal arrangements made under the 1945 Sino-Soviet Treaty of Friendship if the United States did intervene (including access to Port Dalian). The war forced the Chinese to buy the machinery required to rebuild Manchuria as an industrial base from the Soviets. The Soviet Air Force protected Manchuria and northern China from American Air Force incursions during the Korean War while training Korean and Chinese pilots to take their places. The American OPLAN 8-52 to win the Korean War in the event of North Korean refusal of their demands, in early 1953, entailed the use of 480 nuclear fission devices upon Korean and Manchurian railway stations to strangle Chinese supply lines into the country and thereby facilitate a conventional invasion of North Korea. A further 120 weapons were authorised if this proved insufficient.
After the war, Manchuria went on to become a forefront of Chinese industrialization. However, it became a rust belt in the 1990s and is today a decaying industrial region. Recent Chinese policies however, are trying to reverse the trend. Nowadays, the region is currently attracting international attention for the ice and snow sculpture festival held annually in January since 1963 in Harbin, the capital of Heilongjiang. This is possible because the city gets frigid cold in winter; the average January temperature is -17°C.
Also, the PRC authorities encouraged the Manchus to seriously take up their ethnic heritage, something that surprised even some Manchus, being jaded by the Manchukuo and the Chinese Civil War experience. Unlike the Uyghurs and Tibetans, who were at least given an autonomous region, the Manchus had only autonomous counties. This caused some ethnic Manchu to argue for separation from China, albeit in a smaller scale than the Tibetans or Uyghurs' effort and the movement is very unpopular among Manchu today. The Manchus are also the third largest minority group in China, with a population of about 10 million of them (however the Manchu identity included many Han or other ethnic groups who became bannermen rather than actual Manchus). Most of them currently speak Mandarin Chinese, though efforts are being made by the Manchus themselves to revive their nearly extinct language. The Manchu today are again one of the highest achieving ethnic minorities in China and they are very pro-PRC, detesting the rule of the former Republic of China.
Manchuria is also the subject of, for now, largely theoretical disputes between China and South Korea—owing mostly to the presence of North Korea between them. Their dispute is over two topics. First, Manchuria was homeland to a number of ancient and medieval states regarded by modern Koreans as their ancestors—Gojoseon (from which the last Korean kingdom took its name from), Buyeo, Goguryeo, and Balhae. As it were, the last of these kingdoms was extinguished in 10th century when nomadic Khitans conquered western Manchuria and its remnants scattered everywhere—some settled in Korea, some went to Japan, some joined the Jurchens, and so forth—leaving Koreans with nothing more than distant memory and the dispute largely theoretical. More recently, there was a territorial dispute along the Korean-Chinese border that was finally settled in 1910 when, Japan, who had just annexed Korea, unilaterally dropped the issue. This, again, is theoretical since South Korea does not even border the region and the North Korean state has affirmed the boundary as it is. Still, there are ultranationalists in South Korea who insist that there is some validity to Korean claim to parts of Manchuria. Many historical K-drama and movies do take place in Manchuria.
Manchuria IS home to the largest Korean population outside both Koreas, numbering some three million. This is a unique group in that, while they are also the oldest expatriate Korean community. They have also retained Korean language and culture better than their counterparts in Japan or United States, for example. At the same time, however, they are considered among the most loyal ethnic minority to the People's Republic of China.
In Chinese pop culture, Manchuria is often depicted as China's very own Grim Up North, what with it being very close to the nomadic heartland of Mongolia (although the Manchus themselves are famous among the North Asian peoples for not adhering to the Born in the Saddle rule; they're mainly sedentary agriculturalists) and being the starting point of the people who conquered China and started China's last dynasty. It's a bit Truth in Television; being the northernmost region of China and just right on Siberia's doorstep, Manchuria has possibly China's worst winters, in spite of its close proximity to the sea.
Works set in Manchuria, or had its residents in fiction:
- The second half of Night Raid 1931 takes place in Manchuria during the Japanese occupation as the Sakurai Agency continues its hunt for renegade IJA officer Takachiho Isao.
- Joker Game's "Asia Express" story arc concerns a murder on a train traveling through the Manchuria region in 1939.
- The Good, the Bad, the Weird is a South Korean film about three Korean bandits in Manchuria.
- The Girl Who Played Go is set during the Japanese occupation of Manchuria.
- The Last Emperor depicts Pu Yi's reign as the puppet ruler of Manchukuo from 1932 to 1945.
- The Manchurian Candidate: the reason why it was called as such is because this is where the titular candidate was brainwashed.
- Part of Jung Chang's family history Wild Swans is set in Manchuria, where her mother was originally from.
- Arrow: The Ultimate Weapon is set on the 1630 Manchu invasion of Korea and had Manchu characters dealing with a single Korean archer who is the protagonist in the story.
- A background subplot in Syphon Filter 2 and 3 involves rogue Chinese general Shi Hao leading a separatist movement in Hēilóngjiāng, the most northeastern province of China. He attempts to buy samples of the Syphon Filter virus to fend off both the Chinese and Russian militaries from claiming control of the province, and sets up a deal with the Japanese Red Army to obtain the virus. The exchange is shut down by Gabe Logan in the third game's opening mission when he snipes all parties involved.