XI Corps in the Pacific

In March 1944 a new headquarters joined General Douglas MacArthur’s forces in the South West Pacific – the staff of the US Army’s XI Corps under Major General Charles P. Hall. War chronologies record under 16 March that the corps “arrived in the Pacific theatre”. In itself this was no great event: the corps brought no divisions with it, only a few hundred officers and men of the staff, signals and services, capable of directing two or three divisions in the field. It was, however, a clear sign that the US Army, which for two years had been fighting in New Guinea with modest forces, was preparing for an offensive on a much larger scale.

The date itself should be treated with caution. According to the unit’s history, XI Corps left the United States for the South West Pacific Area in March 1944 and, on arriving at Finschhafen in New Guinea, was placed under General Walter Krueger’s Alamo Force. The US Army official history (Robert Ross Smith, The Approach to the Philippines), however, still writes at the end of June 1944 that Hall and his staff had “recently arrived in New Guinea from the United States”. 16 March therefore marks the beginning of the corps’ transfer to the Pacific rather than the day on which its staff assumed any combat duties.

A corps from Boston and Chicago

XI Corps had a long, if until then purely paper, history. It had been formed in 1921 as a reserve corps made up of New England units, with its headquarters in Boston, and its shoulder patch – a blue shield bearing a St George’s cross and a green pine tree – recalled a flag from the Battle of Bunker Hill of 1775. Before the war it was never mobilised. It was activated as an active-duty unit only on 15 June 1942 in Chicago, and on 20 October that year Charles Philip Hall took command.

Hall, born in 1886 in Sardis, Mississippi, and a West Point graduate of 1911, belonged to the generation of officers shaped by the First World War. In France he served as adjutant of the 3rd Infantry Brigade of the 2nd Division and fought at Château-Thierry, Soissons and Saint-Mihiel. For his bravery at Vierzy on 18 July 1918 – when he volunteered to go with French tanks into the German-held village and, on the way back, carried a wounded man out from under fire – he received the Distinguished Service Cross. Between the wars he was an instructor at the Infantry School at Fort Benning and a director at the Air Corps Tactical School at Maxwell Field, and in 1930–1932 he served in the Philippines. In 1942 he briefly commanded the 93rd Infantry Division, made up of Black soldiers, before taking over XI Corps.

MacArthur’s army grows

Throughout 1942 and 1943 MacArthur fought the war in New Guinea mainly with Australian troops. The US Army had few divisions in his area and only one corps headquarters – General Robert Eichelberger’s I Corps, which had taken Buna. In 1943 Krueger’s Sixth Army was created, operating as Alamo Force, but operations such as the landing at Finschhafen in September 1943 were still carried out chiefly by Australian divisions.

At the turn of 1943 and 1944 the balance began to change. More American divisions were shipped to Australia and New Guinea, and the landing on Los Negros on 29 February 1944 showed that MacArthur was ready to make long and risky leaps, bypassing strong Japanese garrisons. After the decisions of the Joint Chiefs of Staff in March 1944, which opened the way to Hollandia and on towards the Philippines, MacArthur needed further headquarters capable of running several operations at once. In the course of 1944 more corps headquarters arrived in the South West Pacific Area – besides XI, also X Corps and XIV Corps, transferred from the Solomon Islands – and in the autumn Eichelberger’s newly formed Eighth Army began operating alongside the Sixth. For MacArthur this meant a transition from single operations conducted by one division to campaigns in which two armies fought simultaneously. The Australians, who until then had borne the main burden of the land fighting, increasingly took over garrison duties in the rear.

Aitape and the Driniumor river

The first test came in the summer. On 22 April 1944 the Americans landed at Hollandia and Aitape, cutting off to the east General Hatazō Adachi’s Japanese 18th Army, which was concentrated around Wewak. Adachi decided to break through to the west. When intelligence – including decrypted Japanese signals – pointed to an impending attack, Krueger strengthened the defences of Aitape and entrusted them to Hall. At midnight on 27–28 June the XI Corps headquarters took over the Persecution Task Force, which eventually numbered about two and two-thirds divisions: the 32nd and 43rd Infantry Divisions, the 112th Cavalry Regiment and the 124th Infantry Regiment.

On the night of 10–11 July some ten thousand Japanese attacked across the Driniumor river and broke the American line. The fighting in the jungle lasted until 25 August. Hall, like MacArthur’s intelligence chief General Charles Willoughby, had still doubted in June that the Japanese were capable of attacking, and the first days of the battle forced the Americans back several kilometres. From the end of July, however, a counter-attack from the north outflanked the Japanese attacking near Afua, and the 18th Army’s offensive collapsed. According to the figures given in the literature, the Americans lost about 440 killed and 2,550 wounded, and the Japanese between 8,000 and 10,000 men, including those who died of starvation and disease. Adachi’s army was no longer capable of any major offensive action.

Morotai, Bataan and Corregidor

On 15 September 1944 Hall’s staff, as the Tradewind Task Force, directed the landing on Morotai in the Moluccas – the last stop before the Philippines. The Japanese barely defended the island, and airfields were quickly built on it, from which bombers could reach the southern Philippines and Borneo.

The most important chapter in the history of XI Corps came with the Battle of Luzon. On 29 January 1945 the corps landed unopposed on the coast of Zambales province, north-west of the Bataan peninsula, with the task of cutting off Bataan and opening the way to Subic Bay. At Zig Zag Pass the 38th Infantry Division was held up by Japanese fortifications in the mountain jungle; Hall relieved its commander, and the fighting lasted two weeks. In mid-February the corps’ units cut across and cleared Bataan – the peninsula on which the American and Filipino forces had surrendered in April 1942. On 16 February 1945 paratroopers of the 503rd Regiment were dropped on Corregidor at the entrance to Manila Bay, and a battalion of the 34th Infantry Regiment from the corps’ forces crossed to the island from Mariveles at the southern tip of Bataan. In the spring the corps fought the Japanese Shimbu Group in the mountains east of Manila, where the capital’s water sources were being defended.

In the plans for the invasion of Japan (Operation Downfall) XI Corps was to land at Shibushi Bay on Kyushu. Japan’s surrender meant that in September 1945 its soldiers came ashore at Yokohama as occupation troops. The corps was inactivated on 11 March 1946 at Mito; Hall handed over command a few days later and after the war headed the organisation and training division of the Army General Staff. He died in 1953 in San Antonio.

Place in the war

The arrival of XI Corps in March 1944 changed nothing at the front overnight. It was, however, one of the links in a process that during 1944 transformed MacArthur’s modest forces into a large land army capable of conducting several amphibious operations at once. Thanks to headquarters like this one, after the capture of Manus MacArthur was able to leapfrog along the northern coast of New Guinea – to Hollandia, Aitape and Biak, and on to Morotai – and in the autumn of 1944 to return to the Philippines. Hall’s XI Corps fought along this road almost to the end: from the jungle on the Driniumor to Bataan, where three years earlier the largest surrender in the history of the US Army had taken place.