The battle of Hollandia (22-27 April 1944) was part of Operation Reckless and saw the Americans leapfrog past a series of Japanese bases to capture a key position on the northern coast of New Guinea, catching the Japanese almost entirely by surprise and winning an unexpectedly easy victory.
In the second half of 1943 the main Allied concern in the south Pacific was the major Japanese base at Rabaul. By the end of the year the success of Operation Cartwheel had almost completely isolated that powerful Japanese base, and the successful conclusion of the campaign in western New Britain and the invasion of the Admiralty Islands in the spring of 1944 would complete the circle. Allied attention began to turn to the next stage in the campaign. Originally the Allies had intended to capture Wewak and Hansa Bay, the easternmost Japanese bases on the north coast of New Guinea, but early in 1944 MacArthur decided that he wanted to leapfrog these bases and instead go straight from his position in north-east New Guinea to Hollandia, in the centre of the north coast. Hollandia, and in particular the excellent harbour at Humboldt Bay, was the point from which MacArthur hoped to turn north to carry out his return to the Philippines. It was also far less well defended than Wewak and Hansa Bay, so if the amphibious operation could be carried out safely, the land battles should be easier.
On 12 March the Joint Chiefs of Staff approved the plan, which was given the name Operation Reckless. D-Day was set for 22 April, and MacArthur was promised the support of Nimitz's powerful Pacific Fleet. A sizable deception operation was put in place to convince the Japanese that Hansa Bay and Wewak were still the American target. To further the deception the powerful invasion fleet, some 217 ships carrying 50,000 combat troops and 30,000 support personnel, sailed north-west after it passed through the Vitiaz Straits (between New Guinea and New Britain) and went to Seeadler Harbour, in the newly conquered Admiralty Islands. The Japanese did indeed detect this invasion fleet- they still had reconnaissance aircraft and submarines in the area - but had no idea where it was heading.
