The capture of Kwajalein Atoll

At 4.10 p.m. on 4 February 1944 the commander of the US 7th Infantry Division, Major General Charles Corlett, reported to Rear Admiral Richmond Turner that on Kwajalein Island “all organised resistance had ceased” and that his men were beginning to mop up. Three days earlier, on 1 February, the main landings of Operation Flintlock had begun on Kwajalein Atoll in the heart of the Marshall Islands: in the south on Kwajalein Island itself, and in the north on the twin islands of Roi and Namur, which were assaulted by the 4th Marine Division. The Marines took Roi on 1 February and Namur at noon on 2 February. After the capture of several dozen smaller islets, the whole atoll was declared secure on 7–8 February.

The statement found in war chronologies that the Marines were “mopping up” Roi and Namur on 1 February needs some qualification: 1 February was the day of the assault on both islands itself, and the mopping-up took place mainly on 2 February. Kwajalein is also sometimes called “the largest atoll in the world”. Its lagoon, covering some 2,200 km², is indeed among the largest on Earth and many accounts give it first place, but the answer depends on the criterion used (the area of the lagoon, of the land or of the whole reef structure), and the land area of the atoll’s 93 islets amounts to only about 16 km². Nor was it a great fleet base on the scale of Truk: it housed the headquarters for the defence of the archipelago, a seaplane base, airfields and an anchorage, but the main forces of the Combined Fleet were not stationed there.

An atoll at the heart of the archipelago

The first days of the operation – from the carrier air strikes to the capture of Majuro and of the islets surrounding the main objectives, culminating in the landing on Kwajalein on 31 January – had prepared the ground. On the Japanese side, the defence of the Marshall Islands was directed from Kwajalein Island by Rear Admiral Monzō Akiyama, commander of the 6th Base Force, while Vice Admiral Michiyuki Yamada was stationed on Roi with the headquarters of the 24th Air Flotilla. According to the US Army’s official history (Philip Crowl and Edmund Love), on the day of the landings there were some 5,000 men in the southern part of the atoll and about 3,500 on the northern islands. Only some of them were infantry; the rest were airfield ground crews, sailors, staff personnel and labourers of the navy’s construction units – according to the same source, largely Koreans or Japanese unfit for regular military service.

The Americans had learned from the mistakes of the assault on Betio in November 1943. The landings were made from the lagoon side, in LVT tracked amphibians that could cross the reef; on 31 January the divisional artillery was emplaced on neighbouring islets, from where it could fire directly at the targets; and warships bombarded from close range, using armour-piercing shells. Turner commanded the capture of the atoll for the navy, and the land forces were led by the commander of V Amphibious Corps, Major General Holland Smith. The entire Central Pacific operation was overseen by the commander of the Fifth Fleet, Raymond Spruance.

Roi and Namur

In the north of the atoll the landing was due to begin at 9 a.m. on 1 February, but chaos as the infantry transferred into the tracked amphibians – of which there were too few after the previous day’s fighting for the islets – delayed it by more than two hours. Only at about 11.12 a.m. did the commander of the northern task force, Rear Admiral Richard Conolly, and the commander of the 4th Marine Division, Major General Harry Schmidt, decide to send in the first waves without further delay. At around 11.45–11.50 a.m. Colonel Louis Jones’s 23rd Marines landed on Roi and Colonel Franklin Hart’s 24th Marines on neighbouring Namur. The two islets were joined by a causeway and a sandspit.

Roi, almost entirely taken up by an airfield, was flat and open, and the fire of ships, aircraft and artillery from the neighbouring islets had done its work there. One battalion commander later estimated that of some 400 Japanese killed in his sector, 250 had died before the Marines even landed. The attackers crossed the island in a few hours; at 1.11 p.m. Colonel Jones reported to General Schmidt that it was a “piece of cake”. By evening the island had in effect been taken, and the next day all that remained was to hunt down individual defenders. The real problem was fire discipline: according to the official history, the Marines, going into battle for the first time, fired wildly, endangering their own comrades, until dusk, when their officers restored order.

On Namur, densely built up with storehouses, shelters and barracks, resistance was much stiffer. It was there, too, that the most tragic accident of the whole operation occurred. At about 1.05 p.m. on 1 February a demolition team threw explosive charges into a large concrete bunker that looked like a gun position but was in fact a store of torpedo warheads. The explosion hurled a column of smoke and debris into the air, and an aerial observer reported that “the whole damn island has blown up”. According to Crowl and Love, Marine casualties nearby amounted to between 50 and 100 men, including about 20 killed by the blast and by falling chunks of concrete. By evening the Marines had pushed into the island’s interior, but its northern tip remained in Japanese hands, and the night was spent in clashes with the defenders.

On 2 February the attack was resumed with tank support. At about 12.15 p.m. the northern point of the island was taken, and the fighting was essentially over. Shortly before the end, the commander of the 1st Battalion, 24th Marines, Lieutenant Colonel Aquilla Dyess, was killed while personally leading the attack on the last pocket of resistance. Four Marines received the Medal of Honor for the fighting on Roi-Namur, three of them, including Dyess, posthumously. Between 2 and 7 February the 25th Marines occupied some 55 further small islets in the northern part of the atoll.

Four days on Kwajalein Island

In the south of the atoll everything went to plan. Kwajalein Island, a crescent some 4 kilometres long and at most 800 metres wide, allowed no defence in depth. The Japanese, who until Tarawa had not believed that the Americans could cross the reef from the lagoon side, had placed their strongest fortifications on the ocean shore. The island was bombarded by the ships of the southern task force, among them the battleship USS Tennessee, and by the artillery of the 7th Infantry Division emplaced on the islet of Enubuj (codenamed Carlson). The Army’s official history quotes a soldier as saying the island looked “as if it had been picked up to 20,000 feet and then dropped”.

At 9.30 a.m. on 1 February two of General Corlett’s regiments – the 32nd and 184th Infantry – landed side by side at the western end of the island, on beaches Red 1 and Red 2. By evening they had reached the middle of the airstrip. The following days followed the same pattern: infantry attacks supported by tanks, engineers with demolition charges and flamethrowers, clearing bunker after bunker and shelter after shelter in the rubble of barracks, storehouses and workshops, and at night Japanese counter-attacks and attempts at infiltration, beaten off at close quarters. The heaviest fighting took place on 3 February in the northern part of the island, in the built-up headquarters area the Americans called “Admiralty”, where the infantry ran into concrete shelters and firing positions hidden in the rubble. Rear Admiral Akiyama was killed during the fighting – on 2 February, according to the testimony of a captured member of his staff.

On 4 February the 32nd Infantry took over the whole attack, and in the afternoon its soldiers reached the northern tip of the island. At 4.10 p.m. General Corlett reported the end of organised resistance, although the last strip of the island was cleared only at 7.20 p.m. At the same time, on 3–4 February, the 17th Infantry took the neighbouring islet of Ebeye (codenamed Burton), with its seaplane base, regarded as the second most important point in the southern part of the atoll; according to the Army’s official history, nearly 450 Japanese were killed there and seven were taken prisoner. Over the following days units of the division occupied the remaining islets; most were empty or held by handfuls of men, some of whom took their own lives. According to the chronology of the Marine Corps official history, the whole atoll was declared secure on 8 February.

The balance sheet

Casualty figures vary with the source and the method of counting. The Army’s official history gives 142 killed, 845 wounded and 2 missing for the 7th Infantry Division in the southern part of the atoll, and 737 killed and wounded for the 4th Marine Division, including 190 killed and died of wounds. The Marine Corps official history, which also counts later deaths and the losses of attached units, gives higher figures: 313 killed and died of wounds and 502 wounded in the 4th Marine Division, and 173 killed and 793 wounded in the 7th Division. On any reckoning this was a fraction of the losses suffered two and a half months earlier on Betio, where some 1,000 Marines had been killed in three days.

The Japanese garrison was almost entirely wiped out. According to Crowl and Love’s estimates, 4,938 men were killed in the southern part of the atoll and 206 were taken prisoner – 79 Japanese and 127 Koreans. In the north, Japanese losses were put at 3,563 men, including 3,472 killed; 51 Japanese and 40 Korean labourers were captured. Among the dead were also forced labourers from Korea, who had been brought to the Marshall Islands to build fortifications and airfields and who had had no say in finding themselves on the front line. These figures come from American calculations made after the battle on the basis of burials and captured documents; the Japanese side left no complete data.

Place in the war

Kwajalein was taken faster and more cheaply than anyone had expected. The reserves – the 22nd Marines and two battalions of the 106th Infantry – were not needed. As early as 2 February it became clear that they could be used elsewhere, and Spruance – after conferring with Turner and Holland Smith on the atoll itself – backed the idea of an immediate strike at Eniwetok, at the western edge of the archipelago. Chester Nimitz approved the plan, and on 3 February Rear Admiral Harry Hill, who was to command the new operation, codenamed Catchpole, flew in to Kwajalein. The landing on Eniwetok, originally not expected until the spring, took place on 17 February, while Rear Admiral Marc Mitscher’s carriers simultaneously struck Truk. The bypassed atolls in the east of the archipelago – Wotje, Maloelap, Mili and Jaluit – remained cut off until the end of the war, bombed and stricken by hunger.

The swift victory confirmed that the lessons of Tarawa had been learned: long and accurate bombardment, artillery on neighbouring islets, tracked amphibians and tank–infantry cooperation made it possible to take fortified atolls without slaughter on the beaches. The Japanese drew their own conclusions from the defeat. Since the shoreline could not be held under the fire of the American fleet, on the Marianas, Peleliu, Iwo Jima and Okinawa they defended themselves inland, in caves and systems of fortifications, which greatly raised the price of subsequent landings.

Kwajalein became a base for the further offensive: in June 1944 the American fleet sailed from its lagoon and from Majuro for the Marianas, and the rebuilt airfields on Roi and Kwajalein housed aircraft that bombed the bypassed atolls and the Carolines. After the war the Marshall Islands came under United States administration as a UN Trust Territory, and Kwajalein still serves as an American missile range, the Ronald Reagan Ballistic Missile Defense Test Site. Most of the Marshallese who work at the base live on neighbouring Ebeye, one of the most densely populated islands in the Pacific.