This is mainly due to the heavy criticism received from other countries because of Japan's actions involving China.
Japan invades the rest of China
This move initiates World War II in the Pacific. Japan wanted to expand to be a powerful empire, and their desire for growth fueled them to challenge China, the most dominant superpower in that region, in order to prove Japan to be a great empire.
Japan invades French Indochina (Vietnam)
This intensifes Japan's conflict with the United States and Great Britain, who both react with an oil boycott. The U.S. also places an embargo on Japan by prohibiting exports of steel, scrap iron, and aviation fuel to Japan, due to Japan's actions.
Japan signs a neutrality treaty with the Soviet Union
This helps to prevent an attack from that direction if they were to go to war with Britain or the U.S. while taking a bigger bite out of Southeast Asia.
Japan occupies southern Indochina
Two days later, the U.S., Britain, and the Netherlands freeze Japanese assets. This prevents Japan from buying oil, which will, in time, cripple its army and make its navy and air force completely useless.
Japan takes territory and oil, starts to plan Pearl Harbor attack
With the Soviets seemingly on the verge of defeat by the Axis powers, Japan seizes the opportunity to try to take the oil resources of Southeast Asia. The U.S. wants to stop Japanese expansion but the American people are not willing to go to war to stop it. The U.S. demands that Japan withdraw from China and Indochina, but will simply have settled for a promise not to take more territory. Japanese planning staff is beginning to study the 1940 British air attack on the Italian fleet at Taranto.
General Tojo Hideki makes a secret arrangment
Hideki, the new leader of the country who was anointed in mid-October, secretly sets November 29 as the last day on which Japan will accept a settlement without war. At this time, Japan is pursuing two simultaneous courses: try to get the oil embargo lifted on terms that would still let them take the territory they wanted, and to prepare for war.
Japanese forces bomb Pearl Harbor
The result is 2,403 dead, 188 destroyed planes and a crippled Pacific Fleet that include 8 damaged or destroyed battleships.
Japanese begin a day-long attack, war is declared
Approximately three hours after the initial Pearl Harbor attack, the Japanese commence their attack on American facilities in the Philippines. Farther to the west, the Japanese strike at Hong Kong, Malaysia and enter Singapore to attack Thailand in a coordinated attempt to use surprise in order to inflict as much damage as quickly as possible to strategic targets. It is on this day, as well, that the U.S. and Britain declare war on Japan.
China also declares war on Japan
China also declares war on Germany and Italy, the Axis powers. China does this because of their aggressive conquests which were not appearing to cease anytime soon.
Japanese invade Philippines, capture Guam
They also begin landings on northern Luzon, the biggest of the Philippine Islands.
Japanese invade Burma
Their objective in Burma was initially to capture of Rangoon, the capital and principal seaport. This would close the overland supply line to China and provide a strategic bulwark to defend Japanese gains in Malaya and the Dutch East Indies.
Japanese invade Hong Kong
The first wave of Japanese troops land in Hong Kong with artillery fire for cover and the following order from their commander: "Take no prisoners." The Japanese quickly take control of key reservoirs, threatening the British and Chinese inhabitants with a slow death by thirst. The Brits finally surrender control of Hong Kong on Christmas Day.
Japan captures Indonesia, takes over Dutch Borneo
The resulting oil shortage and failures to solve uprising conflicts influence Japan to capture the oil rich Dutch East Indies, known now as Indonesia, and Japan takes over the northern region of Dutch Borneo, an island which separates into runei, Indonesia and Malaysia. In time, the Japanese eventually take over much of Dutch Borneo.
Japan invades Singapore
They do this because Singapore is a British colony. The British surrender on February 15, 1942.
Air raid against Darwin, Australia
The Japanese organize the biggest air raid against Australia since Pearl Harbor. They also invade Bali at this time.
Japanese attack U.S.
This is their first attack against U.S. mainland. A submarine shells an oil refinery near Santa Barbara, California.
First air raid on Japan: Doolittle Raid
America plans for 16 B-25B Mitchell Bombers to attack the mainland of Japan in retaliation after Pearl Harbor. A few buildings are bombed, three pilots die in accidents, and eight are captured. However, the Doolittle Raid inspires the head of Japan's navy to extend his country's defensive perimeter all the way to Midway Island.
Battle of Midway
The Japanese draw the U.S. Pacific Fleet into battle so as to overwhelm and destroy it. An invasion is planned by them on Midway Island which will provide a base for attacking Hawaii, but a U.S. admiral uses decrypted Japanese radio intercepts to counter the offensive. An aircraft attacks and sinks four Japanese carriers, forcing the Japanese to withdraw.
Japan attacks the U.S. Navy
A major U.S. naval disaster off Savo Island, north of Guadalcanal, as eight Japanese warships wage a night attack and sink three U.S. heavy cruisers, an Australian cruiser, and one U.S. destroyer, all in less than an hour. Another U.S. cruiser and two destroyers are damaged. Over 1,500 Allied crewmen are lost.
Japanese execute American POWs
In late December 1941, the Japanese reinforce existing forces on Wake Island, a place where American troops were also residing. After more Japanese are sent over, their power was overwelming, and many Americans are either killed in battle or put in camps. The remaining 100 of them are blindfolded and shot.
Japan attacks China
Japan attacks U.S. air bases in eastern China. This is their last offensive in China.
Second air raid on Japan: B-29 raids
A B-29 Superfortress, a four-engine propeller-driven heavy bomber, is flown by the Americans over Tokyo on November 1, 1944. The first bombing raid against the city, however, occured on this day. The B-29's aim for the Musashima engine factory from 30,000 feet up, but many struggle with their accuracy. Of the 111 planes on the raid, only 24 find the target.
Third air raid on Japan
This raid against was on Japanese bases in Indochina. This raid was performed by U.S. Carrier-based planes.
Battle of Iwo Jima
Iwo Jima is a tiny island which is strategically important to the U.S. for their bombing excursions, but it is considered Japanese soil. By March 16th, the island is declared secure and all resistance ceases by March 26th. It takes America over one month to capture it. The Marines lose 6,891 men and 18,070 are wounded. Of the 22,000 Japanese soldiers, only 212 are taken as prisoners. The battle shows the Americans how far the Japanese will go to defend their country.
Japanese begin to withdraw from China
The main reason for this is because the war is coming to a close and they want to better defend their homeland.
Atomic Bombs are dropped on Japan
Over the course of a few days, the U.S. fly planes over Japan and drop atomic bombs on the cities of Hiroshima and Nagasaki. Roughly 250,000 people are killed, many of which are civilians.
U.S.S.R. declares war on Japan
This is on the day in between the two bombings of Hiroshima and Nagasaki. One million Soviet soldiers into Japanese-occupied Manchuria, northeastern China, to take on the 700,000-strong Japanese army. Japan had not been too worried about the Soviet Union, so busy with the Germans on the Eastern front. The Japanese army went so far as to believe that they would not have to engage a Soviet attack until spring 1946. But the Soviets surprise them with their invasion of Manchuria.
Japanese in Korea surrender
Conscription of Japanese males for the military efforts of World War II led to organized official recruitment of Koreans to work in mainland Japan. However, the end of Japan’s rule in Korea was due to its defeat in the war.
The United Nations is born
This is an official indication that the war is over.