Dutch East Indies Campaign - Background

Background

The East Indies was determined to be one of Japan's primary targets if and when it went to war because the colony possessed abundant valuable resources, the most important of which were its rubber plantations and oil fields; the colony was the fourth-largest exporter of oil in the world, behind the U.S., Iran, and Romania. The oil made the islands enormously important to the Japanese (see below), so they sought to secure the supply for themselves. They sent four fleet carriers and a light carrier, along with the four fast battleships of the Kongō class, 13 heavy cruisers and many light cruisers and destroyers, to support their amphibious assaults, in addition to conducting raids on cities, naval units and shipping, in both that area and around the Indian Ocean.

Access to oil was one of the linchpins of the Japanese war effort, as Japan has no native source of oil; it could not produce enough to meet even 10% of its needs, even with the extraction of oil shale in Manchuria using the Fushun process. Japan quickly lost 93 percent of its oil supply after President Franklin Delano Roosevelt issued an executive order on 26 July 1941 which froze all of Japan's U.S. assets and embargoed all oil exports to Japan. In addition, the Dutch government in exile—after the urging of the Allies and with the support of Queen Wilhelmina—broke its economic treaty with Japan and joined with the embargo in August. Japan's military and economic reserves included only a year and a half's worth of oil. As a U.S. declaration of war against Japan was likely, the Japanese planned to eliminate the U.S. Pacific Fleet, which would allow them to occupy the East Indies without American interference. This was one factor that influenced the decision to attack Pearl Harbor.