Operation Persecution

Battle of Aitape and Battle of the Driniumor River

'Persecution' was the US seizure of Aitape on the north coast of North-East New Guinea by Brigadier General Jens A. Doe’s 163rd Regimental Combat Team of Major General Horace H. Fuller’s 41st Division in support of the 'Reckless' landing at Hollandia some 125 miles (200 km) to the west in the Japanese-occupied Netherlands New Guinea (22 April 1944).

Aitape was a small village on the north coast of North-East New Guinea, on the Australian eastern half of the island of New Guinea. Before the war, the village had been notable only for its fairly good anchorage, though this had no adequate shore facilities to support it. The coastal strip on which Aitape is situated is 5 to 12 miles (8 to 19 km) deep and is bounded, in the south, by the foothills of the Toricelli mountain ranges.

Early in early 1942 the Japanese occupied the village in the second-phase offensive which followed the initial 'Centrifugal Offensive'. The Japanese quickly built fighter and bomber airstrips at Tadji, a few miles to the south-east near the coast. The construction of a third airstrip, at a location farther to the west, was abandoned as a result of drainage problems.

'Persecution' was part of the scheme devised by General Douglas MacArthur’s South-West Pacific Area command for Lieutenant General Robert L. Eichelberger’s I Corps within Lieutenant General Walter C. Krueger’s 6th Army to make a rapid 'coast-hopping' campaign to move the US forces to the west along New Guinea’s north coast as rapidly as possible to keep the Japanese off balance and so speed the likelihood of an Allied return to the Philippine islands group.

'Persecution' and 'Reckless' were the first operations of this series, and were undertaken after a careful programme of misinformation which persuaded Lieutenant General Hatazo Adachi that his 18th Army was to be threatened by a frontal assault in the area of Wewak, the next logical target for the combined Australian and US forces which were just completing their 'Postern' reconquest of the Huon peninsula area of North-East New Guinea, where US forces were operating along the coastal region to the north of the Finisterre and Saruwaged ranges, and the Australians in the Markham and Ramu river valleys farther inland.

The objective of 'Persecution' was the isolation of the 18th Army at Wewak, the provision of flank protection against any movement to the west by the 18th Army in the direction of Hollandia, the seizure of Tadji airfield to provide support to the more important 'Reckless' assault on Hollandia after the carriers of Task Force 58 had departed, and the establishment of light naval facilities at Aitape to support further operations.

'Persecution' and 'Reckless' were supported by 217 ships for the transport and protection of the 80,000 men, their equipment, and supplies over 1,000 miles (1610 km) to conduct separate amphibious landings at Aitape and Hollandia deep in Japanese-held territory.

The Hollandia and Aitape operations were thus highly successful masterstrokes, undertaken with the support of Rear Admiral Daniel E. Barbey’s 7th Amphibious Force of Vice Admiral Thomas C. Kinkaid’s 7th Fleet and Lieutenant General George C. Kenney’s 5th AAF together with elements of the Royal Australian Air Force. Close air support of the landings was entrusted to a force of eight escort carriers provided by Admiral Raymond A. Spruance’s 5th Fleet of Admiral Chester W. Nimitz’s Pacific Ocean Areas command.

The invasion force, otherwise the Eastern Attack Group (Barbey’s Task Group 77.1), sailed from Finschhafen and Goodenough island on 16/18 April, and rendezvoused with the carrier force on 20 April in the Admiralty islands group. TG77.1 carried the assault force in three attack transports, one dock landing ship, one attack cargo ship, 16 infantry landing craft and seven tank landing ships, escorted by the destroyers Hobby, Nicholson, Wilkes, Grayson, Gillespie, Kalk and Swanson. Air support was provided by Rear Admiral Van H. Ragsdale’s TG78.1 comprising the escort carriers Sangamon, Suwanee, Chenango and Santee and the destroyers Morris, Anderson, Hughes, Mustin, Russell, Ellet, Lansdowne and Lardner, and Rear Admiral Ralph E. Davison’s TG78.2 comprising the escort carriers Natoma Bay, Coral Sea, Corregidor and Manila Bay and the destroyers Erhen, Walker, Hale, Abbot, Bullard, Kidd, Black, Chauncey and Stembel.

Seaward cover was provided by Rear Admiral V. A. Crutchly’s largely Australian TF74 with the heavy cruisers Australia and Shropshire, and destroyers Arunta, Warramunga and US Ammen and Mullany, and Rear Admiral Russell S. Berkey’s US TF75 with the light cruisers Phoenix, Boise and Nashville (with MacArthur on board) and destroyers Hutchins, Beale, Bache, Daly, Abner Read and Bush.

US estimates put the Japanese strength at some 14,000 men in Hollandia (where the real strength was in fact about 11,000 men, all but 500 of them administrative troops) and about 3,500 in Aitape (where the real strength was about 1,000 including only 250 combat troops).

The Japanese command was in great disarray at the time, the 18th Army having just come under the control of General Korechika Anami’s 2nd Area Army, which had ordered Adachi to pull his two divisions back from the area of Madang and Wewak to Hollandia, Lieutenant General Giichi Itahana having been replaced on 1 April as commander of the 6th Air Division by Lieutenant General Masazumi Ineda for losing most of his aircraft to the series of devastating raids launched against the Hollandia region and its airfields by Task Force 58 (the Fast Carrier Task Force) between 30 March and 3 April, and Rear Admiral Endo having arrived from Wewak at the end of March to take over command of the region’s naval forces.

This meant that local command had devolved on Major General Toyozo Kitazono, previously a transport force commander near Wewak, who had arrived only 10 days before the US landing.

At Aitape the 163rd Regimental Combat Team came ashore near Wapil in nine waves on a two-battalion front without meeting serious interference from the Japanese defence, which had moved inland as the Americans arrived, and by the fall of night had secured Tadji airfield. The initial landing force was then reinforced during the following day by the 127th Regimental Combat Team of Major General William H. Gill’s 32nd Division of Major General Charles P. Hall’s XI Corps, which assumed responsibility for Aitape with a strength that soon rose to 15 infantry battalions and two squadrons of dismounted cavalry.

In this first phase of the operation, the cargo ship Etamin was badly damaged by a Japanese torpedo bomber. No. 62 Works Wing of the Royal Australian Air Force landed in the wake of the 163rd Regimental Combat Team, and had the Tadji airstrip ready to receive Australian Lockheed P-38 Lightning fighters within 48 hours, when 25 Curtiss P-40 fighter-bombers of the RAAF’s No. 78 Wing arrived with the wing’s other aircraft landing on the following day, and a bomber airstrip was ready to handle aircraft by 15 June.

The Imperial General Headquarters now appreciated that the parallel US operations required a complete reassessment of the Japanese position in New Guinea, and on 2 May Adachi was ordered to forget the 1943 defence line (running through Wakde and Sarmi) in favour of a new line running though Biak island and Manokwari, though on 9 May this revised defence line was altered to one running from Sorong to Halmahera, with Biak and Manokwari to be held only as outposts since Allied air attacks from Hollandia had already begun against targets in Netherlands New Guinea, in the process causing severe damage to the convoy bringing in Lieutenant General Yoshio Ishii’s 32nd Division and Lieutenant General Shunkichi Ikeda’s 35th Division to reinforce the 2nd Area Army in that area. The 32nd Division lost one regiment and all its artillery, while the 35th Division was reduced to little more than four battalions with only very limited artillery support.

Once Aitape had been secured, the 163rd Regimental Combat Team was withdrawn to ready itself for operations farther to the west, and was replaced on 4 May by the 32nd Division. The divisional commander, Gill, established a secure perimeter and sent out patrols to watch the movements of Adachi’s 18th Army, which had been cut off by the Hollandia and Aitape landings. On 2 May Adachi was ordered to move via inland jungle trails to western part of New Guinea, a distance of some 400 miles (645 km), to join the 2nd Area Army, but realised that an inland retreat round the US positions in his rear was impossible and instead demanded permission to attack Aitape and Hollandia, using his 20,000 men (including 12,000 administrative and service troops used in the infantry role) in a do-or-die counterattack and thus clear the best route to the west. The Allies were warned well in advance of Adachi’s intentions, likely by intercepting and decoding the messages between Adachi and his superiors, and the I Corps thus had adequate time to deliver reinforcements and prepare a defence line against the Japanese counterattack, since Adachi was so lacking in transport that he was unable to assemble his forces sooner than early July.

It took the 18th Army one month to cover the 90 miles (145 km) through the jungle from Wewak to the Driniumor river, which formed the eastern perimeter of the US defensive position around Aitape, and then another week to organise itself for the attack, which Adachi launched on 10 July.

By this date, the Allied garrison had been reinforced by the arrival of Major General Leonard F. Wing’s 43 Division, the 124th Regimental Combat Team and the 112th Cavalry Regimental Combat Team, which with the 32nd Division were placed under the command of Major General Charles P. Hall’s XI Corps on 28 June. The Americans now had 15 battalions of infantry and two squadrons of cavalry deployed around Aitape. Even so, on 10 July the Japanese managed to drive a hole in the US perimeter. The Americans counterattacked and had regained their original positions by 18 July but Adachi then tried to flank the US perimeter to the south, deep in the jungled foothills of the Torricelli mountains, 6 miles (10 km) to the south of the coast, in the region of Afua village. Here the fighting raged for more than two weeks, and Afua changed hands several times as the battle seesawed back and forth.

Allied naval forces, ranging from US PT-boats to Australian cruisers, patrolled along the coast to the east of the Japanese lines and systematically destroyed the Japanese lines of communication, aided by spotter aircraft from Aitape which allowed the warships to strike accurately at targets as far as 7,000 yards (6400 m) inland.

At the end of July Hall launched an effort to outflank the Japanese, despatching five battalions from the northern end of the Driniumor river to break though the Japanese front and then wheel to the south through the Japanese rear area. But already the shattered remnants of the 18th Army were pulling back the 15 miles (24 km) to the line of the Dandriwad river: 25 days of continuous fighting up to 3 August had finally destroyed the 18th Army as an effective fighting formation.

By 9 August the Japanese had been compelled to attempt a retreat. The US forces now began their own offensive along the coast, driving the shattered remnants of the 18th Army to the south and thus deeper into the jungle, where they dwindled in numbers and capability as a result of starvation and disease until the Japanese surrender in August 1945.

The Japanese dead at Aitape and Hollandia totalled 8,370 and 4,441 respectively, while the figures for the US losses were of 440 and 87 respectively.

Even as Adachi had been making these last desperate attempts to effect a breakthrough to the rest of the Japanese forces on New Guinea, MacArthur had pre-empted him with a series of devastating moves ('Straightline' to Wakde island on 17 May, 'Horlicks' to Biak island on 27 May, 'Cyclone' to Noemfoor island on 2 July and 'Globetrotter' to Sansapor on 30 July), and thus completely isolated the Japanese in New Guinea. The combination of 'Persecution' and 'Reckless' was thus a strategic stroke of the first magnitude. 'Persecution' had also cut off the 18th Army in the area around Wewak south-west of Aitape. Reduced to a mere 35,000 men, the 18th Army was deployed at But on the coast 25 miles (40 km) to the west of Wewak, around Wewak itself, and at Baliffilahop in the Torricelli mountain range 25 miles (40 km) inland to the south-west of But. Many of the Japanese were deployed in small scattered groups in an effort to live off the land, and were this more concerned with tending gardens rather considering offensive operations. The coastal plain in this area was very narrow and cut by numerous rivers and streams, often raging torrents as a result of the region’s considerable rainfall.

The crests of the Torricelli and Prince Alexander mountain ranges paralleled the coast about 10 to 15 miles (16 to 24.5 km) inland, and the narrow spurs running off of these mountains provided excellent defensive positions.

A track, the Old German Road, followed the coast. Major General Jack Stevens’s Australian 6th Division (16th, 17th and 19th Brigades) arrived at Aitape during November and December 1944, and launched a programme of aggressive patrolling to the east, and there followed a number of small actions throughout January 1945. That same month saw stronger Australian advances along the coast and in the mountains as the Japanese began to reinforce their positions in the west. Heavy rain damaged trails and washed-out bridges hampered both sides.

By the middle of March, the Australians were 20 miles (32 km) from Wewak, and the following month renewed their offensive with a slow but steady and methodical advance. The final effort to take Wewak began on 10 May as units attacked directly and others circled to the south. On the following day a small force left But by sea and landed east of Wewak at 08.34 to cut the road. By the end of May the Japanese had been forced into a confined mountain area well away from the coast, so losing any hope of resupply or evacuation. They could not retreat to the east as Major General Alan Ramsay’s (from July 1945 Major General Kenneth W. Eather’s) Australian 11th Division blocked that route. To the south were only hundreds of miles of disease-ridden mountains and jungles.

The Australians continued to press the 18th Army, its three nominal divisions each now reduced to less than regimental strength, right to the end of the war. The Japanese had lost 7,200 men dead since their loss of Aitape in 'Persecution'. The Australians lost 450 men killed and 1,160 wounded.

The 18th Army was finally whittled down to a strength of 13,500 men (all starving and/or diseased) from a strength of more than 60,000 men in June 1943. Adachi surrendered his 18th Army on 13 September. It is estimated that the Japanese had suffered the loss of 100,000 men in eastern New Guinea. A total of 300,000 Japanese, including 20,000 civilian labourers, had been committed to the Solomon islands group, eastern New Guinea, and the Bismarck islands group. Some 60,000 had died in combat and 110,000 by starvation and disease, leaving 127,000 survivors to surrender.