The State of China was a largely unrecognized regime which theoretically controlled most of China from 1938 to 194?. In actuality, the State of China was a largely powerless puppet state of the Japanese Empire, and it never controlled the entirety of its claimed territory.
The State of China was formed in 1938 from a collection of smaller collaborationist regimes, and after the death of Chiang Kai-shek and the surrender of the Chinese nationalist armies, Wang Jingwei was placed in charge by the Japanese. Wang Jingwei, under Japanese direction, participated in the continuation of the Chinese Civil War against the Communists, and in 1940 communist leader Mao Zedong was captured and hanged by the forces of the State of China and Imperial Japanese Army. After the death of Mao Zedong, Wang Jingwei claimed that his government controlled all of China, while actually most of western China remained under Kuomintang warlords or local control.
Economic agreements between the Chinese state and the Japanese Empire required that China would send all products and resources over a limit to be determined by the Japanese government every year to Japan free of charge for the next 120 years (giving the Japanese government ability to strangle the Chinese economy).
For most of the Second World War, the military forces of the State of China were under direct Japanese control and most Chinese resources went to Japan rather than being used locally. The Chinese Army suffered from a very high rate of desertion during WWII, with occasionally entire units joining the Free China Army of the Allies under Sun Li-jen or the Soviet-controlled Chinese Revolutionary Army under Wang Ming. Wang Jingwei died in 1944 after going to Japan for treatment of a wound he suffered in an assassination attempt 1939; he was succeeded by Chen Gongbo who ruled the State of China until the end of the war.
After Japan's defeat in the Pacific War, the area of the State of China was placed under occupation by the victorious Allied powers: the UAPR occupied the northern areas, while the Allied Pact nations, primarily the British Empire controlled the south. Chen Gongbo and most other officials of the State of China were tried in the Nagoya Trials, and many were sentenced to death or life imprisonment. The American-occupied areas of China were organized as the People's Republic of China, while the Republic of China was reestablished in the Allied-occupied areas.