1. THE IMMEDIATE CAUSE OF THE WAR
In June 1940, with Britain undermined by Hitler’s victory over France, the Japanese forced the closure of the Burma Road, which was an important supply route for the Chinese.
The US banned the export of scrap iron to Japan. This measure had an impact on an already fragile Japanese economy. Japan had to import the food and raw materials it needed to sustain its occupation of Chinese territories (oil and steel). Japan heavily depended of the USA for these goods.
In September the Japanese signed the Tripartite Pact. In November, USA gave the Chinese leader a massive loan to encourage and strengthen their ability to resist Japan.
When Germany attacked Russia in July 1941, Japan attacked and occupied southern Indochina. The USA, Britain and the Netherlands imposed a total trade embargo. Japan was in crisis.

2. If Japan would run out of oil, it meant it could not continue to fight in China.
Japan appeared willing to negotiate, but USA demanded Japan to withdraw from China, that was unacceptable. Japan decided it had to get resources by force.
On December, 2nd /1941, a Japanese fleet began its journey to Hawaii. Without warning on Sunday December 7th, Japan unleashed a 2-hour attack on Pearl Harbor (American naval base). Japan sank or disabled 19 ships, 150 planes were destroyed and 2400 Americans died.
In response, the USA declared war on Japan the following day.

5. THE MOST IMPORTANT BATTLES IN THE PACIFIC
Battle of Singapore – February 1942
Battle of Java Sea – February 1942
Battle of Coral Sea – May 1942
Battle of Midway – June 1942
Battle of Guadalcanal – August 1942
Battle of Saipan – June 1944
Battle of the Philippine Sea – June 1944
Battle of Leyte Gulf – October 1944
Battle of Iwo Jima – February to March 1945
Battle of Okinawa – April to June 1945

7. IMPACTS OF JAPAN’S RELATIONSHIPS
WITH GERMANY
Japan and Germany had some common interests, especially perceiving the USSR as an enemy, which led to the Anti-Comintern Pact of 1936.
When Germany and the USSR signed the Nazi-Soviet Pact, Japan felt isolated, and the pact was signed when Japan was fighting against the Soviet forces near Manchuria.
Japan signed the Tripartite Pact with Italy and Germany, which was primarily designed to deter the USA from becoming more involved in the wars in Europe and Asia. Japan’s policies were linked to the success of their ally.
Three days after the bombing, Hitler declared war on the USA. Hitler abhorred the Americans, he said: “America was a decayed country, the half is Judaized and the other half negrified.”

8. WITH THE USSR
The relationship between these two countries had been tense. Some historians suggested that Japan considered the USSR as the only real enemy. When the Sino-Japanese war started the Soviets were the suppliers of China, and there was fighting between Japanese and Soviet troops on the Manchurian border.
The Russians were now focused on the threat posed by Hitler and Japan was willing to sign its own version of the Neutrality Pact with the USSR.
With the launch of Operation Barbarossa in June 1941 (the German attack on the Soviet Union), the Russian thread to Japan ended, Japan attacked south instead of joining in the assault of the USSR. The Soviets declared war on Japan in August 1945.

9. WAS THE USA RESPONSIBLE FOR THE WAR IN THE PACIFIC?
Following WWI, the USA limited Japan’s gains at Versailles and ended Japan’s relationship with Britain.
Japan was also offended when the USA passed a policy in order to cease immigration from Japan to USA.
Japan’s liberal government failed with the success of the Kwantung Army in Manchuria, and as the war of expansion spread in China, the Americans responded by condemning morally and increasing the help for China.
Relations between Japan and the USA deteriorated further with the escalation of the Sino-Japanese war.