Royal New Zealand Air Force
The establishment of Allied air forces on Bougainville and in western New Britain brought Rabaul under fire from two sides. The attacks made on it in December 1943 and early January 1944 reduced its offensive power, but it was still a formidable base capable of putting up a strong defence. An attempt to capture it would have involved the employment of more ground and naval forces than were available in the South and South-West Pacific and would have been a costly affair. On the other hand, its situation lent itself perfectly to the strategy of bypassing which had been practised successfully on a smaller scale in the central Solomons campaign. There were islands to the north which, in Allied hands, would provide bases from which communications with the Japanese strongholds in the Carolines and Marianas could be cut and from which Rabaul could be brought under air attack. It could thus be effectively neutralised until the Allies were ready to take it by direct assault.
The policy of encirclement was decided upon early in 1944. The first objective was Green Island, to the north of Bougainville. It was a coral atoll whose chief islet, Nissan, was suitable for the construction of airfields. Reconnaissance showed that the native population of 1500 was friendly and that it was only lightly held by Japanese, who used it as a staging point for barge traffic between New Ireland and Buka. Its capture by the Allies would not only cut the barge route but would provide an airstrip which would practically halve the distance from Torokina to Rabaul: it was 125 miles from the former and 117 from the latter.
Forces were available in 14 New Zealand Brigade, which was on garrison duty at Vella Lavella, and the operation could have been carried out in the middle of January. It was put off for a month, however, to allow the air forces on Bougainville to soften up Rabaul thoroughly and so minimise the risk of air interference from there.
The next link in the encircling chain was forged on 29 February when troops of General MacArthur's South-West Pacific Command landed on Los Negros which, with the adjoining island of Manus, forms the principal land area of the Admiralty Group. The expedition was planned as a reconnaissance in force, with orders to secure a beach-head if Japanese resistance was not too severe. The troops established their beach-head but opposition was stronger than had been expected, and it took considerable reinforcements and a month's fighting before the group was finally cieared of the 5000 enemy troops who held it.
The Admiralties were important, not only because of their position outflanking Rabaul, but because they contained in Seeadler Harbour one of the best anchorages in the South-West Pacific. There were, moreover, two airfields, Momote and Lorengau, which the Americans put into operation as soon as they had captured them. Within a year after its capture the Allies transformed Manus from a remote tropical island to an immense naval base for the fleets which were to attack the Philippines.
Until March both Admiral Halsey and General MacArthur expected that their next objective was to be Kavieng, on the northern tip of New Ireland, which the Japanese had developed into a base of considerable importance; but after the occupation of the Admiralties the Joint Chiefs of Staff directed that Emirau, in the Saint Matthias Group, 75 miles to the north-west of Kavieng, was to be seized instead.
The troops used were the 4th Regiment of the 3rd Marine Division which was brought up from Guadalcanal, and they occupied Emirau on 20 March against negligible opposition. While the landing was taking place a bombardment force, including battleships, which had originally been detailed to support a landing on New Ireland, stood off Kavieng and shelled it heavily to ensure that the Japanese there could not interfere.
The capture of Emirau completed the encirclement of Rabaul, leaving 50,000 Japanese in New Britain and New Ireland and another 30,000 in Bougainville and Choiseul. From the west the enemy in New Britain was being steadily pushed back towards the Gazelle Peninsula. By early April South-West Pacific forces had advanced eastward to Cape Hoskins in the north and Gasmata on the south coast. As far as the broad strategy of the war was concerned, Rabaul was now out of action and the South Pacific campaign was over. But for the men on the spot there was still page 240 another eighteen months of bitter fighting. The enemy forces in the area had been trapped and the next task was to eliminate them. This was the work in which the Allied air and ground forces in the Solomons and New Britain were to be engaged until the end of the war.
After the initial fighter sweeps and heavy bomber raids of December 1943 the South Pacific air forces began, early in January, a continuous assault on the Rabaul area that was to last until all worthwhile targets had been destroyed. In the first phase, which lasted until the end of February, the primary objective was the five airfields which the Japanese had developed on the Gazelle Peninsula. The aircraft used were heavy bombers (B24s), medium bombers (B25s), and light bombers (SBDs and TBFs). Fighter protection was provided by F4Us, F6Fs, P38s, P39s and P40s, including two squadrons of the RNZAF Fighter Wing.
The attacking forces operated from numerous bases which the Allies had captured or built in the Solomons. The heavy bombers came from Munda, and the light bombers and fighters from Bougainville, Stirling and Barakoma.
In spite of losses the Japanese air force continued to put up fighter opposition until 19 February, after which it ceased. After the elimination of the Japanese air force in New Britain the town of Rabaul was continuously attacked by Allied bombers. The attack began in earnest on 28 February and by 17 March the American Command calculated that Rabaul was 67 per cent destroyed. It had been divided into fourteen target areas, which were systematically wiped out one by one.
In the second week in March the Allies turned their attention to areas outside the town where the Japanese had built up huge dumps of supplies. The first to receive severe bombing attacks was the village and plantation of Vunapope to the south of Blanche Bay.1 The attack was opened on 10 March by twenty-four New Zealand P40s, each armed with a 500-pound high-explosive bomb. On that date there were over a thousand buildings and tents in the area. A month later photographic reconnaissance showed that only 160 small buildings and supply dumps remained.
After Vunapope had been disposed of, the supply areas at Rataval and Talili Bay had their turn. There the Japanese had stored their main supplies of ammunition and bombs. By the middle of May these areas were largely destroyed.
With the three main storage areas apparently wiped out, the smaller supply and personnel concentrations were attacked—in the plantations around Keravat, Vunakanau and Tobera airfields, on Matupi Island and in the Kabanga Bay region.page 241
From early in March P38s, P39s, and P40s were fitted to carry bombs. The usual bomb-load for P38s was, to start with, two 500- pound bombs, and for P39s and P40s one 500-pounder. Later the bomb-load for all three types was doubled.
After 23 March the heavy bombers of the South Pacific air force were used against Japanese bases at Truk and Satwan and took little further part in the operations against Rabaul. The attack was carried on by medium, light and fighter bombers. From the middle of March a squadron of American PBJs was added to the striking forces and used mainly for night bombing. While different types of targets were attacked in turn, the airfields were struck continuously. The Japanese showed great persistence in repairing them, and to keep them unserviceable the Allies dropped more bombs on them than on all the other Rabaul targets combined. The greater part of the attack was carried out by SBDs and TBFs working together. The SBDs normally went in first to bomb the anti-aircraft batteries, primarily to destroy the guns and secondarily to put the gunners off their aim and force them to take cover. The TBFs followed immediately and planted their bombs on the runways. Fighter-bombers also attacked the airfields but were more generally used against supply and personnel areas. By the middle of May all the airfields were unserviceable except for short periods when the Japanese managed to repair some of them between attacks; 90 per cent of Rabaul township was destroyed; no shipping, other than barges and an occasional submarine, dared to use the harbour; and the major supply and ammunition dumps had been devastated. The destruction of stores was not, in fact, as complete as the Allied photographic intelligence indicated. Since January the Japanese had moved vast quantities underground into caves and a network of tunnels with which they had honeycombed the hills round the town. However, what the bombs had failed to do was eventually accomplished by the dampness of the underground shelters, in which the remaining supplies of ammunition and equipment deteriorated rapidly.