*In the early 20th Century, Japan was a rapidly growing power.  The Meiji Restoration had brought Japan from a Mediæval economy to a modern one. Victories in the Sino-Japanese and Russo-Japanese Wars had established Japan as a major power and its acquisition of German colonies after World War I had confirmed this.  After World War I Japan became a member of the League of Nations.

*Japan was a constitutional monarchy under the Diet and Emperor Hirohito (posthumously the Showa Emperor).

*However, Japan had also developed a strongly authoritarian, nearly fascist, government, with Shinto as a state religion that viewed the Emperor as a god and an embodiment of the Japanese nation.  Unity was so valued that eventually all political parties dissolved themselves to create the Imperial Rule Assistance Association.  The military was also viewed as a the highest expression of national power and will, and the old samurai tradition of bushido (way of the warrior) which valued bravery, honour, and self-sacrifice.  Surrender was out of the question:  a soldier who could not fight any more should commit ritual suicide to avoid the dishonour of capture—and so enemy soldiers who surrendered were treated with disdain and brutality (particularly as Japan had not signed any of the Geneva accords).

*The Japanese empire after World War I included Korea, Formosa, and several small islands in the western Pacific.  They also controlled Port Arthur and the railroads in Manchuria.  They wanted more, though, both as a matter of national pride and because Japan is poor in natural resources.

*On 18 September, 1931, at Mukden, part of the South Manchuria Railway was blown up.  The Japanese blamed it on the Chinese, although many historians believe Mukden Indident was actually created by the Japanese as a pretext for invasion.

*On 19 September, the Japanese attacked Manchuria and by 27 February, 1932 controlled all of Manchuria, which they renamed Manchukuo and placed under the nominal control of Puyi, the last Emperor of China.  In fact, Manchukuo was a puppet state of Japan.  There was guerrilla resistance to Japan’s rule, but it did not accomplish much.  In fact, subsequent agreements bullied China into demilitarised Shanghai and parts of Inner Mongolia.

*In 1933, The League of Nations criticised Japan’s invasion of Manchuria, so Japan withdrew.

*On 7 June, 1937, Japanese soldiers in Peking (allowed there since the Boxer Rebellion) were practising night manœuvres at the Marco Polo Bridge without giving advance as they had been asked to do.  The Chinese were afraid this was an invasion, and fired a few shots.  A Japanese solider went missing, and was (falsely) presumed to be kidnapped.  The Japanese demanded the right to search the area.  Although they were permitted to do so, they moved more troops into the area and by the end of July Japan and China were at war, and Peking was in Japanese hands.

*Some historians think the Marco Polo Bridge Incident was a true accident, others think it was deliberately brought about by the Japanese, and some even think the Chinese Communists may have fired the shots that began the Incident in order to begin a war between Japan and the KMT with the hopes of wearing both sides out.

*The Kuomintang and the Chinese Communists both fought against the Japanese (while also fighting each other) with the covert assistance of the USA and USSR.

*The Japanese invasion of China (sometimes called the Second Sino-Japanese War) was brutal.  The Japanese managed to conquer most of North-Eastern China by about 1940, although they found it difficult to control.

*While conquering China, the Japanese treated the Chinese cruelly.  The most infamous of many incidents was called the Rape of Nanking (Nanjing).  From December 1937 to February 1938, the Japanese Army engaged in rape, murder, arson, and theft, killing civilians—men, women, and children.  The precise number of civilians killed is uncertain, but estimated between 150,000 and 300,000. 

*Elsewhere, the Japanese kidnapped women and forced them to work in military brothels.  Prisoners were kept in terrible POW camps, and in some cases performed medical experiments similar to those performed by the Nazis (although the Japanese also experimented with weapons for biological warfare). 

*The Japanese government often denies that these (and other) atrocities occurred, or says that if they did happen, they have been grossly exaggerated.  Unlike the post-war German government, the Japanese have never apologised for any of their actions during World War II.

*In 1938, Japan invaded the USSR but was defeated in 1939.  In 1941 Japan and the Soviet Union signed a Neutrality Pact that would last until 1945.

*In September, 1940, Japan signed the Tripartite Pact with Germany and Italy, thereby joining the Axis.

*Japan went on to occupy the lands of Vichy France’s Asian empire, taking complete control of Indo-China and creating new puppet states in Vietnam, Laos, and Cambodia.

*In 1942, Japan would pressure Siam (Thailand) into allying with Japan, although Thailand’s main role in the war was allowing Japanese forces to move through its territory, although a few Siamese forces supported Japanese attacks on Burma and China.

*All this was part of Japan’s efforts to create a Greater East Asia Co-Prosperity Sphere, an Asia for Asians (but with the Japanese in charge.

*Japan still needed natural resources, because in response to Japan’s abuse of China and subsequent expansion into French lands, America had passed a series of Neutrality Acts to keep us out of war, but had also cut off shipments of oil, rubber, metal, and other important resources to Japan.

*In October 1941 Tojo Hideki was appointed Prime Minister of Japan.  He began to make plans to expand the Greater East Asia Co-Prosperity Sphere further.  He would alter be implicated in numerous war crimes—authorising eugenics programmes in Japan, the murder of thousands of civilians in conquered lands, the deaths of thousands of POWs, and medical experiments on prisoners.

*Japan was encircled, they said, by ABCD:  the Americans, British, Chinese, and Dutch.  To defend themselves, they had to attack.