Battle of Morotai - Background

Background

Morotai is a small island located in the Halmahera group of eastern Indonesia's Maluku Islands. Most of the island's interior is rugged and covered in thick jungle. The Doroeba Plain in Morotai's south-west corner is the largest of the island's few lowland areas. Prior to the outbreak of war, Morotai had a population of 9,000 and had not been commercially developed. It formed part of the Netherlands East Indies and was ruled by the Dutch through the Sultanate of Ternate. The Japanese occupied Morotai in early 1942 during the Netherlands East Indies campaign but did not garrison or develop it.

In early 1944, Morotai emerged as an area of importance to the Japanese military when it started developing the neighbouring larger island of Halmahera as a focal point for the defence of the southern approaches to the Philippines. In May 1944, the Imperial Japanese Army's 32nd Division arrived at Halmahera to defend the island and its nine airstrips. The division had suffered heavy losses when the convoy carrying it from China (the Take Ichi convoy) was attacked by US submarines. Two battalions from the 32nd Division's 211th Infantry Regiment were initially deployed to Morotai to develop an airstrip on the Doroeba Plain. Both battalions were withdrawn to Halmahera in mid-July, however, when the airstrip was abandoned due to drainage problems. Allied code breakers detected the Japanese buildup at Halmahera and Morotai's weak defenses, and passed this information on to the relevant planning staff.

In July 1944, General Douglas MacArthur, the commander of the South West Pacific Area, selected Morotai as the location for air bases and naval facilities needed to support the liberation of Mindanao, which at the time was planned for November 15. While Morotai was undeveloped, it was preferred over Halmahera as the larger and significantly better-defended island was judged too difficult to capture and secure. The occupation of Morotai was designated Operation Tradewind. The landing was scheduled to take place on September 15, 1944, the same day as the 1st Marine Division's landing at Peleliu. This schedule allowed the main body of the United States Pacific Fleet to simultaneously protect both operations from potential Japanese counter-attacks.

As little opposition was expected, Allied planners decided to land the invasion force close to the airfield sites on the Doroeba Plain. Two beaches in the south-west coast of the island were selected as suitable landing sites, and were designated Red Beach and White Beach. The Allied plan called for all three infantry regiments of the 31st Division to be landed across these beaches on September 15 and swiftly drive inland to secure the plain. As Morotai's interior had no military value, the Allies did not intend to advance beyond a perimeter needed to defend the airfields. Planning for the construction of airfields and other base installations was also conducted prior to the landing, and tentative locations for these facilities had been selected by September 15.