Hollandia

Hollandia, colonial administrative centre on the northern coast of Dutch New Guinea which was occupied by the Japanese in April 1942 at the start of the New Guinea campaign. They built it up into an important air and naval base before units of three of Alamo Force's US infantry divisions (24th, 32nd, and 41st) landed there, and at Aitape, 200 km. (125 mi.) to the south-east, on 22 April 1944.

This first step in MacArthur's drive towards the Philippines was commanded by Lt-General Eichelberger and ultimately 217 warships and 80,000 ground troops were employed. It meant bypassing Wewak and Hansa Bay, which the Japanese had deployed their Eighteenth Army to defend, and leaping some 800 km. (500 mi.) from the nearest Allied base in the Australian mandate of New Guinea. This feat was only made possible by ULTRA intelligence. Because of it the Hollandia operation has been cited ‘as perhaps the classic example of the application of intelligence from codebreaking to operational planning in World War II’ ( E. Drea, MacArthur's ULTRA, Lawrence, Kans., 1992, p. 121).

The prior destruction of Japanese air power at Hollandia by Lt-General Kenney's Fifth US Army Air Force left the Japanese with only 25 serviceable aircraft and neither landing at Hollandia or Aitape was seriously opposed. The inland airstrips were seized in three days and the area was secured by 6 June with minimal losses. On 10 July 1944 the Eighteenth Army counter-attacked at Aitape, but documents captured by Allied Intelligence Bureau patrols, and then ULTRA intelligence, gave ample warning for the US perimeter to be reinforced and for 11th US Corps, commanded by Maj-General Charles Hall, to be formed to defend the front along the Driniumor river. The battle that followed lasted until 25 August. The US defensive line was temporarily pierced, but the Eighteenth Army was virtually destroyed, losing 9,000 men out of the 20,000 committed.