The Japanese move towards the South Pacific began while they were still trying to conquer China. In 1931, the Japanese were in need of raw materials and food to support their small Island country. They decided that the easiest way to remedy these needs would be to occupy China and exploit her natural resources. Japan already had troops in Manchuria to protect the railroad system that delivered raw materials to port for shipment to Japan. Their use of these troops to take over all of Manchuria was very successful. They then embarked on a campaign to secure China's fertile valley regions and by 1938 these regions were under Japanese control forcing the Chinese troops deep into the interior of China. Japan's first turn south came because "once the Japanese left the cities and conquered zones, they ran against a resistance that refused to crack" (Hull, Guidelines #7, pg. 6). They devised a plan to circumvent this resistance by launching attacks into China from the South through French Indo-China. The United States did not like these turn of events and threatened to stop the flow of oil and other supplies to Japan. This was the first major confrontation between the two powers that would fight throughout the Pacific between 1941 and 1945.
The Japanese Navy and Army were both trying to acquire money to fund their expansion. The Army wanted to expand in order to be able to defend the Japanese Empire from the Soviets and to continue operations in China. Fearing they would be left behind, the Navy wanted to sail into the South Pacific to obtain the raw materials Japan so desperately needed. A campaign in the South Pacific would also require what the Navy wanted; a larger better equipped force. The Japanese Cabinet, in their Fundamental Principles of National Policy, stated that Japan would follow a path of slow and peaceful expansion of their influence both to the North and South. This would be accomplished while building up their Army and their Navy was "to be brought to a level sufficient to secure command of the Western Pacific against the U.S. Navy" (Spector pg. 42). This policy set Japan on a path that would lead them to certain conflict with the United States, who would certainly not allow it to happen without their intervention.
Japan's entrance into the Tripartite Pact with Germany and Italy further solidified their position in the Southern Seas by giving them cause to confront Germany's enemies in the Asian Theater. With their Navy threatening British, Dutch and French possessions in the Pacific. The Japanese were beginning to become worried about the possible reaction by the United States. In Washington, the lobbyists for the Chinese were calling for the United States to take action against the expanding Japanese and stated that they "should be forced to draw back from the conquests it had already made" (Keegan pg. 245). Upon learning of Japan's diplomacy in the region, Roosevelt began to tighten the pressure on Japan by placing on them an embargo of Western trade. The Japanese Cabinet reacted by deciding to continue negotiations while preparing for the war with the United States that would take place if the negotiations were to fail. Tojo replaced Prime Minster Konoye after he resigned and set forth on a more militaristic approach to the expansion of Japan's sphere of influence in the Asia Theater. With the failure of negotiations, the Japanese developed plans to attack the United States' bases in the Pacific. They used the same ideology for these attacks that was formulated in 1907. They would attack the American protectorates of Guam and the Philippines believing that they could lure the United States Navy far enough from their supply bases and annihilate them. Secretary of War, Hull, sent word to Japan of the United States final position, the complete withdrawal of Japanese forces from China and the termination of the Tripartite Pact. Tojo regarded these demands as unacceptable and the Japanese Navy set sail towards Pearl Harbor.
The American Pacific Fleet had moved from their home port at San Diego to Pearl Harbor after Germany attacked France in 1940. By December 1941 they were well prepared for war against Japan, but had temporarily let their guard down due to the ongoing negotiations with Japan. On December 7, 1941, most of the Pacific Fleet was in dock and both officers and sailors were enjoying their first day off for some time. This left the port with virtually no defense against the soon to come attack. The American radarmen made a disastrous mistake when they mistook the incoming onslaught of Japanese planes as their Flying Fortresses. The Navy at Pearl Harbor was caught totally off guard when the 183 Japanese aircraft suddenly appeared overhead. In under 30 minutes most of the Pacific Fleet had been destroyed or heavily damaged.
The British Navy would be the next to suffer from the Japanese Southern Operation. In an attempt to counter the Japanese forces landing on the Kra isthmus the “Prince of Wales and Repulse with their small escort of destroyers sailed from Singapore to intercept” (Keegan pg. 256). Unfortunately for the British, the Japanese had already occupied the airfield there and used it to launch torpedo-bomber planes against them. The Japanese succeeded in sinking the Prince of Wales and Rupluse which sent shockwaves throughout Britain, who was not prepared for such a disaster due to her rich naval tradition.
The Japanese continued their Southern Operation and the small island of Guam fell shortly after being attacked. Despite being defended by only a small number of Marines Wake held out and did not fall until 23 December. December 10 marked the beginning of the Japanese assault on Malaya and the Philippines. The British had planned to move their troops to the Kra isthmus to stop the Japanese from landing in Malaya, but as a result of confusion they failed to make the move. When the Japanese landed there the British had no other option but to retreat to better defense positions in their rear. This retreat was a bad move for the British, for they left behind three operational airfields and many valuable pieces of equipment that the Japanese used on their advance towards the British defenses. As the British were being pushed back towards Singapore, most of the units that surrendered were from the local Indian army under the command of inexperienced British officers. With the Japanese at the gates of Singapore and the city's supply lines cut, British Commander, General Percival surrendered the city and over 130,000 soldiers. Although the Japanese were outnumbered at Malaya, they were able to defeat the British, who were without tanks and had too few aircraft. This bitter defeat “has rightly come to be regarded as one of the most shameful allied defeats of the war” (Keegan pg. 257).
Japan's campaign in the East Indies was very important for them because the area was rich with the oil, metal and rubber they needed. Their plans called for the "use of plentiful naval and amphibious forces to attack in close succession at widely separated points across the 2000-mile length of the archipelago: Burma and the Celebes in January, Timor and Sumatra in February, Java in March" (Keegan pg. 262). The allied forces in the region put forth little resistance to the invading Japanese. The local populations welcomed the Japanese because they were unhappy under the rule of the Europeans. With the fall of Burma, the Japanese had successfully executed their first step into the South Pacific.
The day after Japan’s attack on Pearl Harbor the Philippines suffered the same type of attack. Japanese planes launched a surprise attack destroying all the aircraft there and forced the Asiatic Fleet to move to safer waters in the Dutch East Indies. Japan’s strategy was to land forces throughout the island with the hope of drawing MacArthur’s forces away from Manila. After Japan landed a strong contingent of soldiers close to Manila, MacArthur was forced to withdrawal to the Bataan Peninsula, where they were trapped with little supplies. On 12 March President Roosevelt ordered MacArthur to Australia to avoid being captured in the inevitable surrender. Japan launched their final offensive on 3 April and the allied forces crippled by disease and starvation, surrendered within four days. The captured soldiers then embarked on the “Bataan death march” to a prisoner of war camp. During this march over 25,000 had perished. This was seen as one of the greatest atrocities of the war. With the fall of the Philippines the Japanese now had command of almost the entire South Pacific. They had survived all the battles with little loss or damage to their major warships. By using the element of surprise along with expert naval strategy, their Southern Seas campaign was a smashing success.