join the pre-invasion bombardment.|alt=Large naval guns firing on board a ship cast in silhouette The main operation began just after dawn on 26 December with a naval barrage on the Japanese positions on the cape followed by air attacks by the
United States Army Air Forces (USAAF) and
Royal Australian Air Force (RAAF). A total of 14
squadrons from the 1st Air Task Force under Brigadier General Frederick A. Smith, were provided for close air support, of which nine were
bomber squadrons and five were
attack. In addition, several
fighter squadrons flew
combat air patrols to negate the threat from Japanese aircraft: one squadron covered the approaching convoy, three would cover the landing beaches, and another would cover the seaborne elements that would withdraw in the afternoon. These attacks and an aerial smoke screen were followed by the landing of the 1st Marine Division, at Yellow Beaches 1 and 2, to the east near Silimati Point and Borgen Bay, about southeast of the airfield and a diversion at Green Beach, to the west at Tauali, about from Cape Gloucester. The main assault came at Silimati Point with only one battalion landing in the west. After being transported aboard the APDs from Cape Sudest, the force came ashore aboard landing craft of various types including, LSTs and LCIs.
Western landing The diversionary western landing at Tauali (Green Beach), on the Dampier Strait side of the peninsula was assigned to Landing Team 21 (LT 21), consisting of the 2nd Battalion, 1st Marines with a battery of artillery from the 11th Marines. Escorted by two destroyers and two patrol boats, the force was embarked upon 31 landing craft of various types (five LCIs, 12 LCTs and 14 LCMs). They carried with them 20 days of rations and six units of artillery ammunition. After departing Oro Bay with the main convoy, this force had broken off around Finschhafen and proceeded on its own through the Dampier Strait. After a preliminary naval and aerial bombardment around 07:30, the Japanese defenses around Green Beach were found abandoned. LT 21 experienced no opposition coming ashore, preceded by heavy preparatory fires including rockets fired from several amphibious vehicles. The beachhead was established by 08:35 and all first day objectives had been secured by 10:00. Due to interference from the surrounding terrain, the marines were unable to raise their divisional headquarters, and were instead had to relay messages through headquarters Sixth Army (Alamo Force). By nightfall, the marines had secured a perimeter and had cut the coast road, establishing a road block. This prevented the Japanese from using it to reinforce their positions around the airfields, but a secondary route, to the east of Mount Talawe, remained open to the Japanese, having gone undetected by US intelligence. Shortly after the western landing, the Japanese dispatched two companies of the 53rd Infantry Regiment to respond. In the days that followed, the marines clashed with small groups of Japanese, and Japanese artillery and mortars fired on the US perimeter from Dorf Point. Patrol clashes increased until early morning on 30 December when the two companies of the 53rd Infantry attacked the marines around Coffin Corner, exploiting the concealment of a heavy storm and darkness to launch a concentrated assault along a narrow avenue of approach between two defended ridges. Supported with mortars, machine guns and artillery, a five-hour firefight followed before the assault was turned back. Casualties amounted to 89 killed and five captured for the Japanese, against six marines killed and 17 wounded. Following this, there were no further assaults on the western perimeter. Artillery fell on the position on 31 December, but was met counterbattery fire from the 11th Marines who labored to get their guns into action despite the terrain. Although the Japanese sought mainly to avoid contact as most withdrew to support the fighting on the east coast, patrol actions continued throughout early January 1944, when contact was established around Dorf Point with a company-sized patrol from the 5th Marines that had set out overland from the eastern lodgment. The wounded and heavy equipment were subsequently embarked on 11 January, having been hampered by poor weather previously, and LT 21 then collapsed its position, marching east towards the airfields, and on 13 January they linked up with the main body of US troops, who had captured the airfields in late December.
Eastern landing and advance to the airfields The remainder of Task Force 76 consisting of 9 APDs, 14 LCIs, and 33 LSTs were allocated to the eastern zone (Yellow Beaches 1 and 2). The 7th Marines were to go ashore first and were tasked with securing the beachhead, while the 1st Marines – less the battalion assigned to the diversionary landing around Tauali – would follow them up after the initial assault, and would pass through their lines to begin the advance north towards the airfield. The 5th Marines would remain embarked as a floating commander's reserve and would only be released on Krueger's orders. As the task force moved into position, the approaches to the beach were marked and cleared during the darkness, and at 06:00, an hour and 45 minutes prior to H-Hour, a heavy naval bombardment began, with the cruisers engaging targets around the airfields, as well as around the beaches and towards Target Hill. As H-Hour approached, the escorting destroyers also joined in the bombardment, followed by a carefully co-ordinated aerial bombing raid with five squadrons of
B-24s, and one squadron of
B-25s, attacking Target Hill. The first wave of assault troops disembarked from the APDs and were loaded into 12
Landing Craft, Vehicle, Personnel (LCVPs): six were bound for Yellow 1 and the other six for Yellow 2. While the APDs withdrew, the LCVPs began their run to the shore. After the B-25s made a final strafing run over the beach, two rocket-equipped LCIs stationed to the flanks fired onto the beach defenses. Drifting smoke from the aerial bombardment of Target Hill, obscured the beaches and the approaches, and briefly hampered the landing with some troops coming ashore in the wrong spot. Nevertheless, the first wave made landfall around Yellow 1 one minute after H-Hour followed two minutes later at Yellow 2. There was no opposition in the vicinity of these two beaches, but the small group from the 3rd Battalion, 7th Marines which landed northwest of Yellow 1 by mistake came under fire from machine guns firing at maximum range from a number of bunkers after pushing through the thick jungle to locate the coastal trail. Throughout the morning, follow-up troops from the remainder of the 1st Marines came ashore and pushed through the 7th Marines, to begin the advance north towards the airfields. The landing area to the north of Borgen Bay, was surrounded largely by swamp, with only a small narrow beach along which the Marine infantry and their supporting Sherman tanks from the
1st Tank Battalion could advance towards the airfields. This slowed the advance inland and resulted in heavy congestion on the beaches, hampering the unloading process. After initially being diverted towards Arawe in the morning, Japanese aircraft, after refueling and rearming at Rabaul began attacking the Allied ships around the landing beaches around 14:30, resulting in the loss of the destroyer with over a hundred of her crew and casualties aboard the destroyers and . Nevertheless, around 13,000 troops and about 7,600 tons of equipment were pushed ashore during the first day of the operation on either side of the cape, and the attacking Japanese aircraft suffered losses to US fighters and ship-borne anti-aircraft fire. Opposition in the main landing area was limited initially to rear-area troops that had been overrun but a hasty counterattack by the 2nd Battalion, 53rd Infantry Regiment (Major Shinichi Takabe), which had marched from Nakarop, lasted through the afternoon and evening of the first day, falling mainly against the 2nd Battalion, 7th Marines under Lieutenant Colonel
Odell M. Conoley. By the end of the day, the 7th Marines held the beachhead, while the 11th Marines had brought their artillery pieces ashore and the 1st Marines had begun a slow advance north, forced into a long column along the narrow trail. The following day the marines advanced westward, pushing towards their objective, before reaching a Japanese blocking position, identified by the marines as Hell's Point, on the eastern side of the airfields. This position was well concealed, and equipped with anti-tank and 75 mm field guns. Teams from the
19th Naval Construction Battalion (designated as the 3rd Battalion, 17th Marines) worked to improve the routes along which the US forces were advancing as large quantities of supplies were landed. Amphibian
landing vehicles were used to ferry ammunition forward, but the volume of traffic, coupled with the heavy rain, churned up the narrow coastal road. As a result, the movement of combat supplies forward from Yellow Beach, as well as evacuation of the wounded back from the engagement areas, proved difficult. On 28 December, a secondary landing beach – Blue Beach – was established about closer to the fighting to reduce the distance supplies had to travel ashore. At the same time, the blocking position was attacked and US armor was brought up. Nine Marines were killed and 36 were wounded, while Japanese losses amounted to at least 266 killed. The 5th Marines, which had been in reserve for the initial landing, were landed on 29 December. There was some confusion during the landing due to a last minute change in orders for the regiment to land on Blue Beach instead of Yellow Beach 1 and 2. As a result, the regiment came ashore in both locations, with those who arrived on the Yellow Beaches route marching to Blue Beach or being ferried by truck. After establishing themselves ashore, the 5th Marines carried out a flanking move to the south-west, while the 1st Marine Regiment continued to advance along the coast. By the end of the day, the marines had broken through the Japanese defenses and were in control of most of the airfield. Japanese air attacks ended on 29 December, when bad weather set in. This was followed by much US air activity around Rabaul, which prevented further air attacks on Cape Gloucester. During the final days of December, the marines overran the airfield and expanded their perimeter, incorporating Razorback Ridge, a key feature about to the south of No. 2 Strip running north to south. In early January, Company E, from the 2nd Battalion, 5th Marines effected a link up with the western lodgment around Dorf Point on the western coast.
Advance to Borgen Bay In the weeks that followed the capture of the airfield, US troops pushed south towards Borgen Bay to extend the perimeter beyond Japanese artillery range. In this time, further actions were fought by the 5th and 7th Marines against the remnants of the 53rd Infantry Regiment and the 141st Infantry Regiment, which had undertaken a march north across difficult terrain from Cape Bushing, following the initial landings. On 2 January, there was a sharp engagement around Suicide Creek, when the advancing marines came up against a heavily entrenched defending force from the 53rd Infantry. Held up by strong defenses that were well concealed amongst the dense jungle, the marines were halted and dug-in temporarily around Suicide Creek. The following day, a reinforced company from the Japanese 141st Infantry Regiment launched an unsuccessful counterattack on the US troops around Target Hill. This was followed by renewed fighting around Suicide Creek, as the Japanese put up a stubborn defense, which was eventually overcome with the assistance of tanks and artillery on 4 January. After reorganizing on 5 January, US troops secured Aogiri Ridge and Hill 150 on 6 January. This was followed by an action towards the high ground around Hill 660. Slowed by bad weather, rugged terrain and Japanese resistance, progress for the marines around Hill 660 was slow. The position was finally secured on 16 January 1944 following three days of fighting in which 50 marines and over 200 Japanese were killed. The capture of this position represented the end of Japanese defensive operations in the Cape Gloucester and Borgen Bay areas. Following this, Matsuda withdrew with around 1,100 troops, ceding the area to the Americans, who captured his command post intact. ==Base development==