China from about 1800 to about 1970.
In 1800, China was doing ok, and was still a great power, but then....
The Taiping rebilion/civil war: 20 to 40 million casualties.
It came close to rivaling WWII.
famine after Taiping rebelion further depopulates the country.
Punti-Hakka clan wars: 1 million
Russians take over Outer Manchucria. Japan and Western countries force the Chinese to agree to "unequal treaties". forcing China to open up to westerners. During second half of 19th century, China is exploited by imperialistic powers.
In 1900, Chinese try to stop the European imperialism. After a short war, and a siege of Beijing, foreign soldiers were allowed in Beijing in the most humiliating treaty in Chinese history.
In 1911, the Qing empire collapsed. A period of Warlordism follows. At least 2 million dei itn teh fighting.
In 1931 the Japanese annex Manchuria and establish a puppet state of Manchukuo.
In 1936 to 1945 the Japanese invade, and a long war is fought. The war devastated China leaving 15 million casualties, and 100 million refugees. The Japanese commited many atrocities while in China.
From 1945 to 1949, a Civil war erupted between the Kuomintang and the Communists. Mao Zedong of the Communists won, and the war costed some 4 million casualties.
In 1950 to 1953 Mao Zedong ordered the army to fight in Korea. Chinese took heavy casualties, as much as a million by some estimates.
During the 50's, and 60's, Mao Zedong created the "Great Leap Forward". It was designed to make the Chinese economy great again, but was poorly planed. Millions of peasants were forced from their lands into the factories creating a famine of 30 million casualties.
The "Clutral Revolution" led to the near destruction of Chinese ancient heritage and identy.
After Mao Zedong was gone in 1976, China's sufferings finally began to end. Even today though, China has a dictatorship, though it is freer then it was under Mao.
The amount of suffering of China was incredible. I'm surprised it has hardly been mentioned.