Fighting for the Marshall Islands

Name and dates

The Marshall Islands campaign is the name given to the American amphibious offensive of late January and February 1944 in which Admiral Chester Nimitz’s Central Pacific forces wrested the archipelago’s most important atolls from the Japanese. The main part of the campaign bore the code name Flintlock and comprised the capture of the atolls of Majuro and Kwajalein; its extension was Operation Catchpole – the capture of Eniwetok Atoll (Enewetak) on the north-western edge of the archipelago. Both were covered by a great carrier strike on the Japanese base at Truk in the Carolines, Operation Hailstone.

The battle is framed by the dates 31 January and 23 February 1944. The first is D-Day of Operation Flintlock: on the morning of 31 January the first American troops went ashore on the small islets of Kwajalein Atoll, while Rear Admiral Harry Hill’s task group occupied Majuro without a fight (a Marine reconnaissance company had landed there during the night of 30–31 January). The second marks the end of mopping up on Parry Island at Eniwetok, which the Marines had taken on the evening of 22 February. Rear Admiral Marc Mitscher’s carriers struck the Marshalls from 29 January, and battleships and cruisers shelled them from the night of 29–30 January – this was preparation for the battle, not its beginning. According to the chronology of the official history of the US Marine Corps, Kwajalein Atoll was declared secure on 8 February, although Kwajalein Island itself had fallen on 4 February. Smaller atolls with few or no Japanese were still being occupied by the Americans in March and April 1944, while the strongly garrisoned Wotje, Maloelap, Mili and Jaluit were bypassed – these operations no longer belong to the battle.

Background

The Marshall Islands – several dozen low coral atolls scattered in two chains, Ratak and Ralik, across more than a thousand kilometres – belonged to Germany before 1914. Japan seized them in the first months of the First World War and after the war administered them as part of the League of Nations’ South Seas Mandate. In the 1930s the Japanese closed the islands to foreigners; the Americans suspected that fortifications were being built there in breach of the terms of the mandate, but knew little about them. For Japan the archipelago formed the outer ring of its defences, and from the 1920s pre-war American plans for a war with Japan had assumed that the fleet would have to pass through the Marshalls on its way west. In the first months of the war American carriers merely harassed them – the best-known example being the raids on the Marshall and Gilbert Islands of 1 February 1942.

In 1943 the Combined Chiefs of Staff agreed that alongside General Douglas MacArthur’s advance through New Guinea and the Solomon Islands, the United States would conduct a second offensive – across the central Pacific, with the forces of Nimitz’s Pacific Fleet. The Gilbert Islands were chosen as the first step, needed as an air base for reconnoitring and bombing the Marshalls. In November 1943 the 2nd Marine Division took Betio on Tarawa Atoll in the bloody Battle of Tarawa, and Army troops occupied Makin. The fighting for the Marshall Islands had been planned since the summer of 1943 as the next leap: the first plans called for the capture of the atolls of Wotje and Maloelap in the east of the archipelago, and only afterwards of Kwajalein.

Tarawa changed those plans. At a conference on 7 December 1943 Nimitz proposed bypassing the eastern atolls and striking straight at Kwajalein, in the very heart of the archipelago. The commander of the Fifth Fleet, Vice Admiral Raymond Spruance, the commander of the amphibious forces, Rear Admiral Richmond Kelly Turner, and the commander of V Amphibious Corps, Major General Holland Smith, were against it – they feared that aircraft from the untaken atolls would threaten the supply lines. According to Turner’s later account, Nimitz listened to their objections at three successive conferences and did not change his mind. He took the final decision on 12 December in a discussion with Spruance: to strike at Kwajalein and simultaneously at Majuro, which was almost ungarrisoned but made a good fleet anchorage. The date, originally set for 1 January 1944, was postponed to the end of the month.

The boldness of the plan rested to a great extent on intelligence. The Americans were reading Japanese radio traffic and knew that after the fall of the Gilbert Islands the Japanese had been reinforcing above all the eastern atolls – Wotje, Maloelap, Mili and Jaluit – which were closer to the Americans, while Kwajalein was more weakly held, largely by support personnel.

Forces and the lessons of Tarawa

The Marshall Islands came under the Japanese Fourth Fleet of Vice Admiral Masami Kobayashi, who commanded from Truk. According to some studies there were about 28,000 Japanese soldiers, sailors and labourers across the archipelago in January 1944, scattered over a dozen or so atolls. Kwajalein, one of the largest coral atolls in the world, was home to Rear Admiral Monzō Akiyama’s 6th Base Force, the headquarters for the defence of the whole archipelago, while in the north of the atoll, on the islets of Roi and Namur, joined by a causeway, lay an airfield and the headquarters of the 24th Air Flotilla of Vice Admiral Michiyuki Yamada, who from December 1943 directed Japanese air operations in the Marshalls. The American official history puts the defenders of Kwajalein at about 8,000 – just over 3,500 on Roi-Namur and about 4,500 in the southern part of the atoll – but only some of them were combat troops; the rest were airfield personnel, sailors and labourers, many of them Korean. The defence was strung out along the shores, without depth: the narrow islets of the atoll left no room for it. On 4 January 1944 General Yoshimi Nishida’s 1st Amphibious Brigade arrived at Eniwetok from Manchuria via Truk; some of its battalions were sent on to other atolls, but enough remained at Eniwetok to rebuild the defences there.

The Americans prepared the operation so as not to repeat Tarawa, where about a thousand Marines had died in 76 hours. Turner and Smith’s landing force numbered – according to the American historian Gordon Rottman – more than 46,000 men. Rear Admiral Richard Conolly’s Northern Attack Force carried to Roi-Namur the new 4th Marine Division of Major General Harry Schmidt, which was going into its first battle; Turner’s Southern Attack Force carried the 7th Infantry Division of Major General Charles Corlett, which had fought on Attu in May 1943. The reserve consisted of the 22nd Marines and the 106th Infantry Regiment of the 27th Division, later earmarked for Eniwetok.

Almost everything that had failed on Betio was changed. The naval bombardment lasted not a few hours but several days; the battleships closed in and also fired armour-piercing shells, which penetrated concrete shelters. Schmidt’s division received 240 LVT tracked amphibious vehicles and 75 armoured, gun-armed LVT(A)s, so that the entire assault wave could cross the reef without wading. On the first day the islets next to the main objectives were seized and field artillery was emplaced on them, so that it could then support the assault at close range. For the first time in an offensive in the central Pacific, special command ships with full communications equipment were used, and improvised teams of frogmen – the forerunners of the later Underwater Demolition Teams – reconnoitred the reefs and beach approaches. The Fifth Fleet was also assembled for the operation, with Mitscher’s fast carrier force (Task Force 58): six fleet carriers and six light carriers, screened by new fast battleships.

Preparation: carriers and warships

From as early as November 1943 B-24 bombers of the US Seventh Air Force, flying from the Ellice Islands and later from airfields in the Gilberts, attacked Mili, Maloelap and Wotje. On 4 December Rear Admiral Charles Pownall’s carriers struck Kwajalein and Wotje; that night a Japanese aircraft torpedoed the carrier Lexington, which nevertheless returned to Pearl Harbor under her own power. In January land-based raids became a daily occurrence: they were meant to destroy Japanese air power and at the same time mislead the enemy as to the real objective.

On 29 January 1944, two days before D-Day, all four of Mitscher’s carrier groups went into action. According to the American official history, Rear Admiral Alfred Montgomery’s group (the carriers Essex, Intrepid and Cabot) shot down over Roi 11 of the last 20 fighters Yamada sent up and destroyed the airfield; the groups of Rear Admirals Frederick Sherman, John Reeves and Samuel Ginder struck Kwajalein Island, Taroa on Maloelap Atoll and Wotje. From the night of 29–30 January fast battleships and cruisers shelled Roi-Namur, Taroa and Wotje, and on 30 January the bombardment and air strikes extended to the whole of Kwajalein Atoll. Japanese air power in the Marshalls had practically ceased to exist even before the landings – the only serious air counter-attack came as late as 12 February, when a night raid by bombers – probably from Saipan, via Truk – destroyed a large part of the supplies stockpiled on Roi.

The battle: Majuro and Kwajalein (31 January – 8 February)

During the night of 30–31 January the reconnaissance company of V Amphibious Corps landed on Majuro from the high-speed transport Kane. An English-speaking local told the Marines that the Japanese had left the atoll – only one naval petty officer and a few civilians remained, and they were soon captured. On the morning of 31 January Hill’s task group entered the lagoon with the 2nd Battalion, 106th Infantry; the bombardment of the main island was called off when it became clear there was no one to shoot at. Majuro was taken without loss, and within a few days its spacious lagoon had become a forward anchorage for the Fifth Fleet.

That same day on Kwajalein Atoll the Americans were seizing the small islets. In the north, Marines of the 4th Division took five islets around Roi-Namur and set up artillery on them; confusion in transferring troops to the amphibious vehicles, wind and heavy seas delayed the follow-on waves, but resistance was negligible. In the south the 7th Infantry Division occupied four islets next to Kwajalein Island and on one of them, Enubuj, emplaced the divisional artillery – four battalions of 105 mm howitzers and a battalion of 155 mm howitzers.

The main landings began on 1 February. On Roi, an islet almost entirely taken up by the airfield, the 23rd Marines crossed the island in a few hours; by evening Roi was in American hands, and most of the defenders had already been killed by the bombardment – an officer of one battalion estimated that of about 400 Japanese dead in his sector, 250 had fallen to the shelling. Namur, densely built up and overgrown, cost more. The 24th Marines ran into shelters and bunkers, and at 1.05 p.m. Marines who threw explosive charges into a large concrete bunker blew up a store of torpedo warheads. A column of smoke rose several hundred metres into the air and a hail of concrete and debris fell on the islet; the blast and two smaller explosions killed about 20 Marines and wounded about a hundred. Namur was declared taken before noon on 2 February. The Japanese command on both islets had ceased to exist earlier: according to the American official history, Yamada and many of his staff officers had been killed during the bombardment of the headquarters building.

In the south the 7th Infantry Division landed at 9.30 a.m. on 1 February on the western tip of Kwajalein Island – a narrow strip of land about four kilometres long with an airfield. Fire from battleships and cruisers and from the artillery on Enubuj – according to the official history, the division’s batteries alone fired about 25,000 shells at the island – shattered the beach defences; one soldier said afterwards that the island looked as if it had been picked up to 20,000 feet and then dropped. The Japanese had expected a landing from the ocean side, but the Americans came from the lagoon, crossing the reef in amphibious vehicles. The 184th and 32nd Infantry Regiments nevertheless advanced slowly: the defenders held out in ruins, shelters and shell craters and tried counter-attacks and infiltration every night. Rear Admiral Akiyama was killed – according to the testimony of a captured member of his staff – on 2 February. On the afternoon of 4 February the island was declared taken. At the same time the neighbouring islets were cleared, among them Ebeye with its seaplane base (3–4 February), and on 8 February the whole atoll was declared secure.

The outcome surprised the Americans themselves. Of the nearly 8,100 defenders of Kwajalein, only a few hundred survived – most of them labourers, often Korean – while the two divisions together lost fewer than 500 dead, half as many as the Marines on Betio. The reserves that were to have supported the fighting for Kwajalein if needed remained untouched. Nimitz flew to Kwajalein on 5 February and approved an immediate attack on Eniwetok, previously planned for May at the earliest.

The battle: Truk and Eniwetok (17–23 February)

Eniwetok, some 600 km north-west of Kwajalein, had an airfield on the islet of Engebi and was needed as a forward base facing the Marianas and the Carolines. Operation Catchpole was entrusted to the task group of Marine Brigadier General Thomas Watson – the 22nd Marines and two battalions of the 106th Infantry, about 10,000 men in all – under the cover of Rear Admiral Hill’s ships. American intelligence estimated the atoll’s defenders at about 800 men; only documents captured on Kwajalein and aerial photographs revealed that, after the arrival of Nishida’s brigade, there were several times as many.

The landing was covered by the largest American carrier strike since the start of the war. Truk in the Carolines, called by the Americans “Japan’s Pearl Harbor” and “the Gibraltar of the Pacific”, had been the Combined Fleet’s main forward base since 1942, and its airfields threatened Eniwetok. However, after an American reconnaissance aircraft flew over in early February, Admiral Mineichi Koga, the successor of Isoroku Yamamoto, withdrew most of his ships – to Japan and to Palau. On 17 and 18 February three of Mitscher’s carrier groups, with nine carriers, carried out Operation Hailstone. Aircraft and warships sank, among others, the light cruisers Katori and Naka, four destroyers and some thirty merchant ships, including valuable tankers – about 200,000 tons according to most estimates – and destroyed more than 250 aircraft. Spruance’s battleships and cruisers, circling the atoll, finished off fleeing ships. During the night of 17–18 February a Japanese aircraft torpedoed the carrier Intrepid, which had to return for repairs. Truk ceased to be a fleet base, and soon afterwards the Japanese withdrew the remnants of their air power from Rabaul.

At Eniwetok on 17 February the Americans seized the small islets at the entrances to the lagoon and set up artillery on them. On 18 February the 22nd Marines landed on Engebi and took the islet after a few hours of fighting that cost 85 dead. On 19 February the 106th Infantry landed on the main island of Eniwetok, where the bombardment had been lighter; the Japanese, hidden in spider holes and camouflaged shelters under the palms, let the first waves pass and struck them from behind, so a Marine battalion was committed and the attack was pressed at night as well. The island was declared taken on 21 February. On 22 February, after heavy fire from battleships, the Marines landed on Parry Island, where Nishida kept the brigade’s reserve; by evening organised resistance had essentially ended, and on 23 February mopping up on the islet was completed. Nishida was killed in the fighting on Parry.

Losses

Casualty figures vary depending on the source and on whether they include the Navy. The official history of the US Marine Corps states that on Kwajalein the 4th Marine Division lost 313 killed and died of wounds and 502 wounded, and the 7th Infantry Division 173 killed and 793 wounded; on Eniwetok the Marines lost 254 killed and 555 wounded, and the 106th Infantry 94 killed and 311 wounded. Gordon Rottman gives 313 killed, 77 missing and 879 wounded for Eniwetok. Added together, the official history’s figures give more than 800 American killed and died of wounds and about 2,200 wounded for the whole campaign; some tabulations give 611 killed, 260 missing and 2,341 wounded.

Japanese losses were almost total. According to American figures, about 7,800 defenders were killed on Kwajalein and about 250 men were taken prisoner (Rottman: 166 on Kwajalein Island and 87 on Roi-Namur), many of them Korean labourers. At Eniwetok about 3,400 Japanese were buried; the prisoners numbered just over a hundred. In all, therefore, more than 11,000 Japanese soldiers, sailors and labourers died in the fighting for the Marshall Islands. Operation Hailstone cost the Japanese an estimated 4,500-plus dead, and the Americans about 40 dead and 25 aircraft.

Significance

The fighting for the Marshall Islands showed that the lessons of Tarawa had been learned. A long bombardment, amphibious tractors for entire assault waves, artillery on neighbouring islets and more efficient command made it possible to take three atolls in under four weeks and at a lower price than Betio alone. Kwajalein was also the first territory held by Japan before the war to be taken from it by the Americans – a breach of the outer ring of Japanese defences. The speed of the victory allowed Nimitz to bring his timetable forward by several months: Eniwetok was taken in February instead of May, and the strike on Truk revealed that the base, feared since the start of the war, was largely empty. The Americans bypassed it, just as they had earlier bypassed Rabaul in the south (the operations on Bougainville and New Britain).

The strongly garrisoned eastern atolls – Wotje, Maloelap, Mili and Jaluit – were left to themselves. Their garrisons, bombed until the end of the war and cut off from supplies, suffered hunger and disease, and according to post-war accounts a large proportion of the soldiers died of starvation and sickness. Mili was the first of the bypassed atolls to surrender, on 22 August 1945. This way of waging war – taking only what was needed and cutting off the rest – became the hallmark of the central Pacific offensive.

Majuro and Kwajalein became great fleet and air bases. From then on the fast carriers sortied from the Majuro lagoon, and in June 1944 the invasion forces for the Marianas – Saipan, Guam and Tinian – passed through Kwajalein and Eniwetok. The Japanese drew their own conclusion from the defeat: a defence right on the shoreline, smashed by naval gunfire, stood no chance. On Saipan, Peleliu, Iwo Jima and Okinawa they defended themselves inland, which made the subsequent battles far bloodier. After the war the Marshall atolls became a United States trust territory; nuclear tests were carried out at Bikini and Eniwetok, and an American military base still operates on Kwajalein today.