Inspired by the German officer coup against Hitler's Germany, Japanese democratic movements began to organize with assistance from perhaps outside sources. Soon enough, an attempted coup d'etat fell into a civil war between the Toseiha faction and the new civilian government of Japan. Democracy eventually won out.
The civil war in Japan led to Korean independence as well as the freedom of Manchukuo which subjugated the Mongol Military Government. The civil war also affirmed Chiang Kai Shek's internal pacification policy, which he followed through and sent ultimatums to the warlords and Manchukuo.
The democratic parties begin cooperating with the Japanese Communist Party to help eliminate militarism and fascism completely from the state. The Showa Constitution is instituted, following the constitution of the United Kingdom. Afterwards, Japan, realizing that imitating Westerners was inherently wrong and decided an approach of Asian co-operation by forming the West Pacific Treaty Organization, or WPTO for short. Japan then declared itself the Pacific Guardian and demanded mandates in Malaysia, Indochina, and Indonesia from the Western colonial powers. They agreed.
Manchukuo was beginning to become an ugly relic of Japanese colonialism. In 1937 China began attacking Manchukuo and Japan decided to prepare an invasion too of Manchukuo to help China. Japan recognized the independence of Korea and invited it to the WPTO. In December 1937, Japanese forces stationed in Korea invaded Manchukuo, which collapsed in March 1938. Japan, using its role as Pacific Guardian managed to secure independence for the Philippines in May 1938 and ended its mandates over former European colonies in June 1938.
China's only enemy wasn't only Manchukuo. In July 1938 Japan helped out an intervention against the Chinese Soviet Republic, and since it had no foreign support since the Soviets were entangled in civil war, a slow fold would occur due to the terrain of the Shaanxi base area. Either way Japan assisted China in invading the Mongolian People's Republic and the Tuvan People's Republic, which relatively quickly collapsed. On May 25, 1940, Yan'an was captured and the Communists collapsed after.
In the background, after the UK invaded Iran, it formed an alliance with Italy in 1939. In 1940 Nazi Germany (who won the civil war in 1939) supported a rebellion in India which dragged them in although as co-belligerents in a separate faction. Lithuania had been reforming the Polish-Lithuanian Commonwealth, including all Baltic States.
In August 1940, Japan, realizing the aggression of the Soviet Union, and Japan's status as an anti-communist bulwark, guarantees the PLC. War broke out soon afterward, with a long war capitulating the Soviets in January 1943. In the peace conference, all three powers formed reconstruction zones, however Japan and China disagreed with the border between their reconstruction zone, Japan thinking they were treated unfairly by China when China was the second-rate power. This caused a small rift between the two nations, however it was repaired.
Soon afterwards, in February 1943 the WPTO (now including the PLC) invaded Germany. Berlin fell April-May 1943 and the Nazi regime tumbled in May 1943.
Afterwards, the Allies and WPTO turned against the Italians, collapsing their regime.
A Cold War begins between the two democracies as Japan has been speaking very anti-colonialistically of the Western Powers. Only time will tell who will win this Cold War.