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.
The battle of Hollandia was fought in the area between Humboldt Bay in the east and Tanahmerah Bay in the west, a stretch of coast about twenty five miles wide. Hollandia town was on the western shores of Humboldt Bay, and the two towns were separated by the short Cyclops Mountain range. These mountains reached up to 7,000 feet, but were quite narrow. They were bordered to the south by Lake Sentani, a fifteen mile long crescent shaped lake that ran parallel to the coast. Hollandia was linked to Lake Sentani by a reasonable road, but elsewhere routes were limited to tracks. Most of the known Japanese defences were on this route, and so the original plan was for the main thrust to be made from Tanahmerah Bay. The Allies had very limited knowledge of the Hollandia area. An attempt to land a scouting party before the invasion ended in failure when the party ran into hostile locals, who informed the Japanese of their presence.
The Japanese had 11,000 men at Hollandia, under the command of Masazumi Inada. They had built three airfields further inland on the shores of Lake Sentani, and the roads from the coast to the lake were protected by a series of defences. However most of the 11,000 men were support staff, either running the coastal base, the supply dumps or the airfields, or were airmen whose aircraft had been destroyed in five major Allied air raids in the previous few weeks. The airfields were run by the 6th Air Division of the 4th Air Army and at their peak were nearly as powerful as the airbases at Rabaul. As a result the Japanese had at least 300 aircraft at Hollandia before the start of the Allied offensive. There were probably only around 500 ground combat troops at Hollandia, all of them from anti-aircraft units.
Humboldt Bay was used as a transhipment point, where larger vessels coming from safer waters were unloaded and their cargos transferred into coastal barges for the dangerous run along the New Guinea coast.
The attack was carried out by General Eichelberger's I Corps, with the 24th Division and most of the 41st Division (the 163rd Infantry was detached to carry out the Aitape landing). Before the attack the 24th Division was training for amphibious and jungle warfare on Goodenough Island while the 41st was resting in Australia after fighting in Papua and at Lae and Salamaua. Air cover was provided by the fast carriers of Task Force 58, while the escort carriers were used at Aitape.
The Fifth Air Force raids devastated Japanese air power at Hollandia. Between 30 March and 3 April they destroyed over 300 Japanese aircraft, with 100 lost on 30 March alone. By 6 April the Japanese only had 25 serviceable aircraft at Hollandia and they never recovered.
The invasion fleet left Seeadler on 21 April and headed north-west. After dark they turned south and finally headed for Hollandia and nearby Aitape. The Japanese were caught entirely by surprise and only realised that Hollandia was the American target when the landings began.
American troops landed at two points near Hollandia. Most of the 41st Division landed at Humboldt Bay, the largest anchorage on the northern coast of New Guinea. Hollandia town was on the edge of this bay. The 41st landed on two beaches, and quickly secured their position.
The 24th Division landed 22 miles further to the west, at Tanahmerah Bay. The attack was preceded by a naval bombardment from the 8-in cruisers HMAS Australia and HMAS Shropshire and a mix of Australian and American destroyers. The only Japanese resistance to the assault was small arms fire from the fringes of the bay and an island in the harbour. This were quickly suppressed and caused no casualties. Neither of the beaches used at Tanahmerah Bay were defended, and the beachhead was very soon secured. The lack of local knowledge caused problems for the 24th, which found its main landing beach faced impassable swamps, and its secondary beach was lined with coral that limited landings to high tide only. The swamps covered areas that had been earmarked for camps and supply dumps. That night the US commanders decided to concentrate on the Humboldt Bay area. The convoy due to reach Tanahmerah Bay on 24 April was diverted to Humboldt Bay as were all of the HQ units, most of which were stuck in ships off shore at Tanahmerah.
Once the beachheads had been secured the Americans began a two-pronged assault on Lake Sentani. By the end of 22 April the troops coming from the west had reached six miles up the road, once again passing unmanned defences. The western force ran into an ambush on 23 April, which held it up for the rest of the day. At this point supply problems forced the Americans to pause while they built up some reserves of supplies. The advance resumed on 25 April and the Americans found that the Japanese had retreated. On 26 April the advancing Americans began to outrun their supplies, which had to be carried by hand along the muddy tracks. General Irving, commander of the 24th, decided to gamble on a successful air drop and limited resistance, and ordered the advance to continue. By noon the airfields were in sight and patrols reached the westernmost of the three. A two pronged assault on this airfield (Hollandia Drome) was almost unopposed, and the airfield was secured by 15.30 on the afternoon of 26 April. That evening a patrol pushing east from the airfield met up with the leading elements of the force coming up from Hollandia.
The 41st Division had faced fewer problems on its beaches. The landings were supported by a heavy naval bombardment, which forced the Japanese away from the beaches. The Americans found abandoned meals inside the dugouts that had been built to protect the beaches, but didn’t have to fight their way past them. Amongst the abandoned positions was an intact anti-aircraft gun that could easily have fired on the beach and a series of strong defensive positions on hills overlooking the beaches. The landing area was soon safe enough for General MacArthur to land in person. On the first day the Americans only lost six dead and sixteen wounded. Hollandia town fell without any resistance on 23 April, and the 41st began the drive inland towards the airfields.
The advance began at 8am on 23 April. Very little resistance was encountered, although there were some attacks on the right flank of the advance during the afternoon. The advancing troops paused for the night not far from the eastern shore of the lake, where they expected to encounter more serious resistance. On this flank the supply problems weren't quite as bad as in the west, although even a number of amphibian LVTs that had been allocated to the force sometimes struggled in the mud.
On 24 April the advance resumed, and by just after noon the Americans had reached the eastern end of the lake, and captured a jetty where the main road reached the water. By the end of the day the division had secured a beachhead along the lake.
The plan for 25 April was to move the LVTs from the coast to the lake, and use them in a combined amphibious and overland advance along the lake towards the three airfields, which were located on a flatter area inside the crescent of the lake. This attack met with limited opposition. The main target for the day, the village of Nefaar, was captured easily and the rest of the day was spent patrolling to the west. One patrol even reached Cyclops Drome, the eastern field. Strong Japanese defences were reported here, but when the Americans attacked on 26 April the Japanese had gone. The third airfield, Sentani Drome, was captured by 12.15, again without running into any significant resistance.
By 27 April the airfields had all been captured, and the Hollandia task force had achieved their main objectives. The rest of the campaign was largely dominated by patrols sent out to try and find the vanished Japanese garrison, but most of the missing men had escaped to the west, at the start of a desperate journey towards the nearest Japanese bases. The Hollandia area was judged to be secure by 6 June.
Japanese resistance at Hollandia had been unexpectedly limited. This appears to have been partly due to a confused command structure. Major General Toyozo Kitazono, the senior officer at Hollandia, only arrived on 12 April, and disappeared soon after the attack (although he did survive the war). Command of the defensive operation was given to General Inada of the 6th Air Division, who issued ambitious orders only to see most of his men flee into the hills early on 22 April. He did manage to organise the one moment of serious opposition on the western front, but by the end of the first day he had issued new orders for an overnight retreat. The Japanese concentrated at Genjem, to the south-west of the lake, and then began a 125 mile retreat west towards Wakde. This march ended in disaster. The Japanese estimated that only 7% of the men who set off ever reached Sarmi and Wakde, and they arrived there just in time to be hit by the next Allied offensive.
The Americans quickly turned Hollandia into a major naval and airbase. It was MacArthur's headquarters until he officially returned to the Philippines after the invasion of Leyte. At its peak Hollandia was home to 140,000 people, with a massive naval base at Humboldt Bay and a series of airfields inland.
The battle for Hollandia cost the Americans 152 dead, and the Japanese 3,300. For once a significant number of prisoners were taken, around 600 men. This was the first time that this number of prisoners had been taken. The remaining 7,000 men of the garrison fled west towards the next Japanese base, 145 miles along the coast at Sarmi. The journey would be horrendous. Lacking the discipline that had kept the losses down on some of the longer jungle treks earlier in the campaign all but 500 of these men were lost before they reached relative safety.
Aitape, to the east of Hollandia, had also been attacked on 22 April and fell after only three days of fighting. However General Adachi, the Japanese commander in the area, wasn't ready to give up without a fight. He ordered 20,000 of his best men to move west from Wewak, and on 28 June they attacked the Americans on the Driniumor River, triggered a battle that lasted into August.