The campaign and subsequent three-and-a-half-year Japanese occupation was also a major factor in the end of Dutch colonial rule in the region.

They sent four fleet carriers (Akagi, Kaga, Hiryū, and Sōryū) 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.

[19] In addition, the Dutch government-in-exile, at the urging of the Allies and with the support of Queen Wilhelmina, broke its economic treaty with Japan and joined the embargo in August.

[14] As a U.S. declaration of war against Japan was feared if the latter took the East Indies, the Japanese planned to eliminate the U.S. Pacific Fleet, allowing them to take over the islands; this led to the attack on Pearl Harbor.

[20][21] In late November, the Netherlands government in the East Indies under the Dutch government-in-exile (already at war with Imperial Japan's Axis power ally Germany in Europe) began preparing for war against Japan itself: ships of the Royal Netherlands Navy were sent to sea and the KNIL Air Force was mobilised.

At that hour, the governor general made a public announcement over the radio that the Netherlands "accepts the challenge and takes up arms against the Japanese Empire.

"[22] Instructions had been telegraphed to the embassy in Tokyo at 02:30, even before news of the attack on Pearl Harbor had reached the Dutch government in London at 04:00.

The instructions were only received on the evening of the next day, and the declaration of war was finally handed to the Japanese foreign minister, Shigenori Tōgō, by the Dutch ambassador, J. C. Pabst, on the morning of 10 December.

The tribunal rejected this, on the grounds that Japan's sole intention was "to give less time to the Netherlands for destroying oil wells.

On 17 December 1941 Japanese forces landed at Miri, an oil production centre in northern Sarawak, with support from a battleship, an aircraft carrier, three cruisers and four destroyers.

[30] Even the combined forces could not stop or even slow the Japanese advance because of their much greater numbers; to face the attacking naval forces, the ABDA command had a conglomerate of ships drawn from any available units, which included the U.S. Asiatic Fleet (fresh from the fall of the Philippines), a few British and Australian surface ships, and Dutch units that had previously been stationed in the East Indies.

Before the Allies had consolidated a new position, they were confronted with a system of air bases from which enemy aircraft operated on their front, flanks and even rear.

[27] By the end of January, Japanese forces had captured parts of the Celebes and Dutch Borneo,[32] and by February they had landed on Sumatra and encouraged a revolt in Aceh.

[34] In addition, the land forces on the islands were quickly overwhelmed, and most major resistance was overcome within two months of the initial assaults, although a guerrilla campaign in Timor was successfully waged for a time.

For such purposes it is, to begin with, entirely inadequate... Our troops have suffered heavy losses, because of the impossibility of protecting them against the enemy's air attacks; they are exhausted... May God be with us.