The Three Power/Tripartite Pact (1940); the Outbreak of War; Pearl Harbor (1941) - Events and Responses Notes

The Anti-Comintern Pact: Japan, Germany, and the Drive to Isolate the USSR

1. We have seen that the army in Japan was a key actor in its expansion. While they were fighting the Second Sino Japanese war, there were plans to expand further.
   1. With that aim in mind, in 1936 Japan and Germany had signed the Anti Comintern Pact.
   2. In 1937, Italy would join the same pact.
   3. The Anti Comintern Pact was an agreement against the USSR.
      1. It stated that the signatories would conduct mutual consultation on measures against Communist “subversion” and commit not to sign agreements with the USSR.
2. The main aim was geopolitical: Germany and Japan wanted to isolate the USSR.
   1. Germany because Hitler´s plans of expansion needed to avoid the possibility of a two front war.
   2. Japan because they wanted to cement their control over Manchuria, which bordered the Soviets.
3. In August 1939, Hitler and Stalin signed the Nazi Soviet Pact (also called the Ribbentrop-Molotov pact).
   1. Japan felt betrayed by Germany, and withdrew from the Anti Comintern pact.
   2. Japanese foreign policy seemed to become more independent, and they declared that they would create a Great East Asian Co-Prosperity Sphere, pooling together Asian nations to rid them from “Western influence”.
   3. With this in mind, Japan entered French Indochina (modern-day Vietnam, Laos, and Cambodia) in June 1940.
   4. France had been the colonial power that controlled Indochina, but after France fell under Nazi rule, Japan pressured the Vichy Regime to allow Japanese troops into northern French Indochina.

Tripartite Pact

1. In September of 1940, Japan will expand into Indochina and start building bases. In parallel, they signed the Tripartite Pact with Germany and Italy.
2. The Tripartite Pact of September 1940 established the the signatories would assist one another with military and economic means if one party was attacked by a country not involved in the European War or in the Sino Japanese conflict.
3. It also established the recognition of spheres of influence in Europe (Germany and Italy) and East Asia (Japan) and Germany renounced its claim to the former colonies it had owned in the Pacific prior to the First World War, which Japan had subsequently acquired.

Japanese Expansion in Indochina

1. At the same time, Japan was still fighting in China. There was a debate within the Japanese military between expanding into the Soviet - Manchurian/Mongolian border or into the South, meaning Indochina.
2. But in September 1939 the Soviets defeated Japanese forces in the Mongolian-Manchurian border and that prompted them to focus on Indochina.
3. In April 1941, after the Tripartite Pact and the already established control of parts of Indochina, Japan signed a Non-Aggression Treaty with the USSR, and further attention was given to Indochina.
4. In July 1941, Japan expands into the South of Indochina, and this is the turning point for the relations between the US and Japan.

US Response

1. The US responded to Japan’s control of Indochina with an oil embargo.
2. The embargo meant that Japan would not be supplied with American oil anymore, and this meant a heavy blow to Japan’s war effort.

Japanese Response

1. Within Japan, there were divergent positions regarding how to respond to the US’ embargo.
2. One standpoint wanted to push for diplomatic negotiations to lift the embargo, but eventually the most ultra nationalist and aggressive stance prevailed, and General Tojo prepared the attack on Pearl Harbor.

Pearl Harbor and the Pacific, 7th December 1941

1. Japan launched a widespread military campaign across the Pacific, targeting multiple Allied positions.
   1. The most significant strike was on Pearl Harbor, the central U.S. naval base in Hawaii.
2. Six aircraft carriers deployed 353 planes in two waves, attacking American ships, airfields, and military installations using bombs, torpedoes, and gunfire.
3. US forces were damaged: four battleships were sunk, and cruiser, destroyers, other vessels and 188 aircraft were lost.
4. Around 2400 people were killed and 1200 wounded.
5. However Japan failed to eliminate key U.S. assets, notably the three aircraft carriers, which were out on maneuvers, and important fuel and torpedo depots.
6. The following day, the United States formally declared war on Japan, marking its entry into World War II.
   1. Although Japan achieved short-term tactical success, the failure to destroy critical American infrastructure contributed to its eventual defeat in August 1945.