The first raid on the Marianas

On 23 February 1944 American carrier aircraft appeared over the Marianas for the first time. All day they attacked airfields and harbours on Saipan, Tinian, Rota and Guam, while reconnaissance aircraft took the first detailed photographs of the islands on which an invasion force was to land four months later. The strike was an epilogue to the fighting for the Marshall Islands and to Operation Hailstone – the raid on Truk of 17–18 February – and at the same time a herald of the next, decisive step in the American offensive in the Central Pacific.

The dates given in the sources differ. American records, kept in Hawaiian time, give 21–22 February, and the US Navy chronology published in 1994 gives 22 February. By local time, on the western side of the International Date Line, the Japanese counter-attack came on the night of 22/23 February and the raid on 23 February; this is also the date given by the US Army’s official history.

Japan’s inner defensive ring

The Marianas lie some 2,300–2,500 kilometres south of Tokyo. Guam had belonged to the United States since 1898, until the Japanese invasion of December 1941; Japan had seized the other islands in 1914 and after the First World War ruled them as a mandated territory. Saipan and Tinian were home to several tens of thousands of Japanese settlers – many of them from Okinawa – and Koreans, working mainly on the sugar-cane plantations.

In September 1943 the Japanese high command had designated an “absolute national defence zone”, to be held at all costs. The Marianas and the Carolines formed its central part: the sea and air routes from Japan to the south ran through them, and their loss would lay Japan itself open to air attack. In February 1944, however, the fortifications were still modest. Only now, after the fall of the Marshall Islands, did the Japanese begin feverishly moving units of the 1st Air Fleet, infantry and artillery to the islands; on 18 February, the day of the raid on Truk, General Hideyoshi Obata’s 31st Army was formed to defend Japan’s mandated islands. The Americans knew very little about the islands – since the beginning of the war not one of their aircraft had carried out proper reconnaissance there.

Spotted on the way

The damage to the carrier Intrepid off Truk forced Rear Admiral Marc Mitscher to regroup Task Force 58. Only two groups went to the Marianas: Rear Admiral Alfred Montgomery’s, with the carriers Essex, Yorktown and Belleau Wood, and Rear Admiral Frederick C. Sherman’s, with Bunker Hill, Monterey and Cowpens. The operation as a whole, like all the Fifth Fleet’s operations, was directed by Admiral Raymond Spruance. The task was twofold: to cover the fighting still going on at Eniwetok by destroying aircraft, ships and installations on Saipan and Tinian, and to photograph the islands for the future invasion.

This time the enemy could not be surprised. On 22 February, while refuelling and on the approach, the force was twice spotted by Japanese patrol aircraft. Mitscher did not turn back; according to an American account of 1946, he told his group commanders to “prepare to fight” and continued westwards. From the evening of 22 February, for about thirteen hours, Japanese aircraft circled near the ships, and three determined attacks were made; among the attackers were twin-engined G4M bombers, which came in low over the water through a barrage of fire. It was the heaviest Japanese air attack on American carriers since the fighting for the Gilbert Islands. According to American figures, of about 40 attackers between 14 and 17 were shot down, and no ship was hit. The force made violent turns, and dense anti-aircraft fire drove off the rest.

The raid of 23 February

In the morning and afternoon of 23 February three waves of aircraft came over the islands – 281 combat sorties in all. Although the Japanese had been warned, resistance in the air proved weak and uncoordinated. American pilots reported shooting down 37 aircraft in the air, and Hellcats strafing the airfields on Saipan, Tinian and Guam burned or damaged nearly a hundred more on the ground. In all the Americans estimated enemy losses at about 150 aircraft; these figures, like most pilots’ claims, may be inflated, but Japanese air power in the Marianas was paralysed for a time. The attackers lost six aircraft.

The results of the attacks on shipping were more modest, because after the night alert the vessels in Tanapag harbour on Saipan had managed to disperse. Aircraft sank or damaged several transports and smaller vessels off Saipan and Tinian. The American submarines deployed around the islands to intercept fleeing ships had better luck: on 22 and 23 February Tang sank an auxiliary gunboat and a repair ship, and Sunfish, together with aircraft, a collier.

The most valuable prize turned out to be the photographs. The pictures taken on 23 February covered parts of Saipan, Tinian and neighbouring Aguijan, as well as Rota and Guam. They were the first material since the beginning of the war on the basis of which staffs could plan a landing. According to the Marine Corps and Army histories, however, the coverage was incomplete and was supplemented only on 18 April; until then the planners relied mainly on these February photographs. After the third wave Mitscher turned back east. Some of the ships, including Yorktown, entered the Majuro lagoon on 26 February; others went to Pearl Harbor and to the United States for repairs.

Significance

The raid closed the February series of strikes which in less than a month changed the balance of power in the Central Pacific. The Marshall Islands were in American hands, Truk had ceased to be a fleet base, and Mitscher’s carriers had twice penetrated deep into the Japanese defence zone and withdrawn without serious loss. According to an American summary, this showed that Task Force 58 could move about the Central Pacific almost freely, limited only by supply and by a possible clash with the entire Japanese fleet.

For the Japanese it was a warning signal. In the following months they moved tens of thousands of troops to the Marianas, although many transports were sunk on the way by American submarines, and the fortifications were still not ready when the invasion came. On 12 March 1944 the Combined Chiefs of Staff decided that Admiral Chester Nimitz’s forces would bypass Truk and strike at the Marianas in mid-June. On 15 June 1944 the Marines landed on Saipan, and the Japanese fleet, trying to stop them, was defeated in the Battle of the Philippine Sea. In July the Americans landed on Guam and Tinian; the fighting on Saipan also cost the lives of thousands of civilians, many of whom committed suicide or were forced to do so. The fall of Saipan brought about the resignation of Hideki Tōjō’s cabinet in July 1944.

The airfields proved to matter most. From Saipan, Tinian and Guam, B-29 Superfortress heavy bombers could for the first time reach Tokyo and most Japanese cities. The first raid from the Marianas on the Japanese capital took place on 24 November 1944, and in 1945 the aircraft that destroyed Japanese cities with incendiary bombs took off from there. Both bombers that dropped the atomic bombs on Hiroshima and Nagasaki in August 1945 – among them the Enola Gay – also took off from Tinian. The way to all this was opened by the photographs taken in February 1944, when Mitscher’s carriers first appeared over the islands.