Japan’s plan to conquer the strategically important oil fields, tin mines, and rubber plantations of the Dutch East Indies entered its final phase with the surprise assault on Bali in order to establish a forward air base in the middle of the Allied defenses. The main attacks fell on Java and Timor later in the month, but before they could happen the main Allied base at Darwin, on the north coast of Australia, had to be neutralized.
The defunct ABDACOM’s main logistical chain for men, weapons and material was India to Singapore, and then Singapore to Surabaya. This was cut with the fall of Singapore the week before. Darwin was the Australian equivalent of the Dutch Surabaya, and the main base for Australian logistical support for Allied, primarily Australian, forces in eastern Dutch East Indies, such as Timor, and New Ireland, New Guinea, New Britain, and the Solomon Islands. It would replace Singapore for Allies still fighting the Japanese. In order to seize the remainder of the Dutch East Indies, Adm Nagumo’s Kido Butai struck Darwin on the morning of 19 February 1942.
The aircraft from the aircraft carriers, Soryu, Hiryu, Akagi, and Kaga (the Shokaku and Zuiakaku were trying find Halsey after the Marshall/Gilbert raids) launched 242 aircraft in the largest naval air raid since their raid on Pearl Harbor, and the biggest attack on mainland Australia in history. The initial attack was a mirror of Pearl Harbor and the woefully inadequate Australian air defenses were crushed. The Japanese aircraft then had free rein to work over the ships in the harbor. A second wave of land based bombers from the Celebes arrived over the defenseless port later that morning and added to the carnage. Eleven Allied ships were sunk and thirty more severely damaged. There would be no chance, if there ever was, of stopping the conquest of the last island chain north of the Australian mainland.
The psychological damage was worse, and Australia became gripped with invasion paranoia. The Japanese Navy, especially the Kido Butai, were seen as the Masters of the Sea, and attributed almost mythical levels of danger and invulnerability.