B-29s in the Marianas

In the second half of October 1944, every few days another four-engined Boeing B-29 Superfortress bomber touched down on the airfield in the south of Saipan in the Mariana Islands. The aircraft flew in from the United States via Hawaii and Kwajalein. This was the start of the largest American air undertaking of the Pacific War: from the islands captured that summer in the Battle of Saipan and in the fighting for Tinian and Guam, the Americans intended to bomb Japan systematically.

Some chronologies state under 23 October that B-29s were already using Tinian as a base for the systematic bombing of Japan. This needs correcting. The first B-29 base in the Marianas was Saipan, not Tinian: the first bomber landed there on 12 October. At the end of October the crews were only beginning training flights; they flew their first combat mission on 28 October, against Truk atoll, and the first raid on Japan – on Tokyo – took place on 24 November 1944. The airfields on Tinian came into use only at the turn of 1944 and 1945. By 23 October, however, construction of the base on Saipan was in full swing.

Why the Marianas

By commonly cited estimates, the B-29 was the most expensive American armament programme of the war, costing more than the atomic project. The bomber had a pressurised cabin, remotely controlled gun turrets and the range to strike targets more than 2,000 kilometres away with a bomb load. In 1943 it was decided to send it against Japan.

The first attempt to use the new bombers, the Matterhorn plan, was a disappointment. The B-29s of XX Bomber Command operated from bases in India and from forward airfields around Chengdu in China, from which in the summer of 1944 they carried out the first raids on Kyushu. Yet every litre of fuel and every bomb had to be flown into China over the Himalayas, and from Chengdu the bombers could reach only the south-western fringes of Japan. The great industrial centres – Tokyo, Nagoya, Osaka – lay beyond their range.

The Marianas had none of these drawbacks. Saipan, Tinian and Guam lie about 2,400 kilometres from Tokyo, which allowed a B-29 to fly to the capital and back, and supplies could be shipped directly from the United States. The commanding general of the Army Air Forces, General Henry H. Arnold, and his planners had pressed for the capture of the Marianas to be brought forward precisely because of the bombers. After the landing on Tinian and the end of the fighting on the island in August 1944, the archipelago became the base for airfields built from scratch.

A separate Twentieth Air Force was created for the B-29s. It answered neither to Admiral Chester Nimitz nor to General Douglas MacArthur, but directly to Arnold in Washington, acting on behalf of the Joint Chiefs of Staff. Its component in the Marianas was XXI Bomber Command, taken over in August 1944 by Brigadier General Haywood Hansell. He was one of the leading theorists of American strategic air power, a co-author of the air war plans of 1941–1942 and an advocate of precise daylight raids from high altitude on key industrial plants.

The airfield on Saipan

The first B-29 base was the former Japanese airfield of Aslito in the south of Saipan, captured by soldiers of the 27th Infantry Division on 18 June 1944, while the fighting for the island was still going on. The Americans named it Isely Field after Lieutenant Commander Robert Isely, a naval aviator shot down over the airfield on 13 June; because of a spelling mistake the form Isley Field stuck (today the site is occupied by Saipan International Airport). The Japanese runway was too short and too weak for bombers weighing more than 60 tonnes. Its expansion was entrusted to the navy’s construction battalions – the Seabees – and to army engineers. Work went on day and night, hampered by rain, a shortage of equipment and Japanese soldiers still hiding on the island. The builders missed their deadline, but in little more than three months they created an airfield with facilities for some 240 bombers of Brigadier General Emmett O’Donnell’s 73rd Bombardment Wing, made up of four bomb groups.

On 12 October 1944 the first B-29, named “Joltin’ Josie – The Pacific Pioneer”, landed on Isley Field with Hansell on board. More aircraft arrived over the following weeks; according to American returns, by 22 November there were already more than a hundred bombers on Saipan. At the end of October, therefore, the 73rd Wing was still in the middle of its transfer. Its crews had had only brief training in Kansas and little experience of long-distance formation flying. Aware of these shortcomings, Hansell decided to fly a series of training missions against nearer targets before attacking Japan.

The first such mission was an attack on the submarine base at Truk atoll in the Carolines, previously devastated by carriers in Operation Hailstone. It took place on 28 October 1944 (27 October in some accounts, by American time). Eighteen bombers took off, four turned back with engine trouble, and the results were meagre – few bombs hit the target. Further raids on Truk, on 30 October and 2 November, went little better. The Wright R-3350 engines, which overheated and caught fire in flight, long remained the B-29’s weakest point.

The Japanese understood what was being built on Saipan. On 1 November an F-13 reconnaissance aircraft, a camera-equipped version of the B-29 later named “Tokyo Rose”, flew over Tokyo – the first American aircraft over the capital since the Doolittle Raid of April 1942. Its photographs made it possible to locate the engine and airframe factories. From 2 November Japanese aircraft from Iwo Jima began night attacks on the Saipan airfields, destroying and damaging bombers on the ground.

Tinian and Guam

Tinian, which chronologies mention under this date, was to play an even greater role in American plans than Saipan, but later. The navy’s 6th Construction Brigade was building there, on the site of the Japanese North Field and West Field, a complex that on its completion in 1945 had six runways each about 2.6 kilometres long. The first B-29s of the 313th Bombardment Wing began arriving at North Field at the end of 1944, and the wing flew training missions from mid-January 1945; West Field received bombers in the spring of 1945. Two more airfields were built on Guam, which from early 1945 also housed the headquarters of XXI Bomber Command. In October 1944 none of these airfields was yet receiving bombers.

Place in the war

The systematic bombing of Japan from the Marianas began on 24 November 1944. A total of 111 bombers took off from Saipan to raid the Nakajima aero-engine works at Musashino near Tokyo, but only 24 attacked the primary target. The jet stream, blowing at altitudes above 9,000 metres at speeds of sometimes more than 300 kilometres an hour, broke up formations and made accurate bombing impossible, and Japan was often covered by cloud. Hansell’s subsequent raids on Tokyo and Nagoya produced similarly poor results at mounting cost.

Under pressure from expectations and from the cost of the programme, Arnold lost patience. On 6 January 1945 General Lauris Norstad relieved Hansell, and command of XXI Bomber Command passed to General Curtis LeMay, until then the commander of the B-29s in China and India. LeMay abandoned the doctrine of precise daylight attacks from high altitude in favour of low-level night incendiary raids on cities. The first of them, on the night of 9–10 March 1945, started a firestorm in Tokyo in which, by various estimates, between about 80,000 and more than 100,000 people died; it was the most destructive single air raid in history. In the months that followed, B-29s from Saipan, Tinian and Guam burned out most of Japan’s great cities and dozens of smaller ones, and also mined its ports and straits from the air. In the spring of 1945 the Americans took Iwo Jima, partly so that damaged bombers could land halfway.

The role that chronologies assign to Tinian in October 1944 fell to it in full in August 1945. On 6 and 9 August B-29s of the 509th Composite Group, among them the Enola Gay, took off from North Field and dropped the atomic bombs on Hiroshima and Nagasaki. The arrival of the first B-29s on Saipan in the autumn of 1944 was thus the beginning of a campaign that within ten months led to the destruction of Japan’s cities and – together with the naval blockade and the Soviet Union’s entry into the war – to Japan’s surrender.