The landing on Kwajalein

On 31 January 1944 the Americans launched Operation Flintlock – the conquest of the Marshall Islands, the first territory that Japan had already held before the war. That day a Marine reconnaissance unit and an Army infantry battalion occupied Majuro atoll in the east of the archipelago without a fight, while at Kwajalein atoll, at its heart, the 4th Marine Division and the Army’s 7th Infantry Division captured nine small islets next to the main objectives of the landing – Roi-Namur in the north and Kwajalein Island in the south. Artillery was emplaced on the islets to support the main landing the following day. This had been preceded by three days of air strikes and shelling: aircraft from Rear Admiral Marc Mitscher’s carriers struck the Japanese bases in the Marshall Islands on 29 January, and on 30 January battleships and cruisers joined the bombardment.

War chronologies often record that the naval shelling and carrier air strikes “began on 30 January”, which needs refining: the carrier strikes of Task Force 58 began a day earlier, on 29 January, and American land-based bombers had been attacking the Marshall Islands for many weeks. What began on 30 January was the naval gunfire bombardment. The landing on the main islands of Kwajalein atoll itself took place on 1 February.

A mandate closed to the world

The Marshall Islands, scattered over hundreds of thousands of square kilometres of the central Pacific, were a German colony until 1914. Japan seized them at the start of the First World War, and after the war received them as part of the League of Nations South Seas Mandate. In the 1930s the Japanese closed the mandate to foreigners, and in the United States it was widely suspected that, in breach of the mandate’s terms, they were building fortifications there. Airfields and bases sprang up on the atolls, and from them, in December 1941, the forces that attacked Wake Island set out. Kwajalein, one of the largest atolls in the world, housed the headquarters of Rear Admiral Monzō Akiyama’s 6th Base Force, responsible for the defence of the archipelago.

Since the 1920s, successive versions of American war plans against Japan had assumed that the route across the central Pacific would lead through the Marshall Islands. The first American strike on them came as early as 1 February 1942, when aircraft from the carriers Enterprise and Yorktown attacked Kwajalein, among other targets – but that was only a raid. The United States was ready for a real offensive only at the end of 1943, when dozens of new carriers, battleships and landing ships joined the fleet. The first step was the capture of the Gilbert Islands – Tarawa and Makin – in November 1943, from where airfields could be built and the Marshall Islands reconnoitred from the air.

Straight to the heart

The original plans envisaged taking the archipelago step by step, starting with the eastern atolls closest to the Gilbert Islands – Mili, Maloelap and Wotje – where the Japanese had airfields and their strongest garrisons. After the experience of Tarawa, Admiral Chester Nimitz, commanding the forces in the central Pacific, changed the concept. Aerial photographs and intercepted signals showed that the Japanese were reinforcing precisely the eastern atolls, while Kwajalein, lying deeper inside, remained more weakly defended. According to a widely cited account, at a conference at Pearl Harbor in mid-December 1943 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, argued against the leap to Kwajalein, fearing Japanese aircraft from the bypassed atolls at their backs. Nimitz held his ground: the objective would be Kwajalein. The eastern atolls – Wotje (PL), Maloelap, Mili and Jaluit – were to be bypassed and neutralised from the air. To secure an anchorage and build an airfield, the lightly defended Majuro was to be occupied.

The lessons of Tarawa

The bloody assault on Betio in November 1943, in which about a thousand Marines were killed in three days, was analysed at Pearl Harbor in detail and without indulgence. The conclusions were built into the preparations for Flintlock. Above all, the bombardment was to be longer, heavier and more accurate: ships were to close in nearer the shore and fire armour-piercing shells at specific, identified bunkers rather than simply blanket the island with fire from a distance. At Tarawa the bombardment had lasted a few hours; at Kwajalein it was to last several days. The commander of the northern landing force, Rear Admiral Richard Conolly, who ordered his battleships to close in exceptionally near the shore, earned the nickname “Close-in Conolly”.

Secondly, the number of LVT tracked amphibious vehicles – the so-called amtracs, which at Tarawa had been the only craft able to cross the reef – was increased. This time the entire first wave was to go in aboard amtracs, accompanied by armoured versions mounting cannon and howitzers. Thirdly, it was planned to seize neighbouring islets before the main landing and to emplace field artillery on them that could fire on targets at close range. Underwater Demolition Teams, which reconnoitred the reefs and the approaches to the beaches, were also used in combat for the first time. The landing commanders directed the operation from new command ships fitted with extensive communications – at Tarawa, communications failures aboard the battleship Maryland had paralysed command.

The forces were enormous. According to the American official history and the studies based on it, several hundred ships took part in the operation, and the landing force alone numbered more than 40,000 men: Major General Harry Schmidt’s 4th Marine Division, going into battle for the first time, and Major General Charles Corlett’s 7th Infantry Division, a veteran of the fighting on Attu, plus reserves. Facing them, according to the most frequently cited estimates, were about 8,000 men on Kwajalein atoll – about 5,000 on Kwajalein Island and about 3,000 on Roi-Namur – including a large proportion of aviation personnel, construction workers and Korean forced labourers rather than infantry.

Three days of fire

The assault began on 29 January. The four carrier groups of Task Force 58 – according to American figures, twelve carriers with about 700 aircraft – attacked the airfields on Roi, Kwajalein, Maloelap and Wotje, and then Eniwetok. Japanese air power in the Marshall Islands, already weakened by earlier raids by bombers from the Gilbert Islands, was practically wiped out within two days; over Kwajalein atoll the Americans enjoyed complete command of the air. On 30 January the fast battleships went into action, followed by the older battleships, cruisers and destroyers of the landing forces, which shelled Roi-Namur and Kwajalein Island as well as the bypassed atolls of Wotje and Maloelap. An American soldier quoted in the Army’s official history later said that Kwajalein Island looked “as if it had been picked up to 20,000 feet and then dropped”.

31 January: Majuro and the islets

Operation Flintlock formally began on 31 January at Majuro. During the night and in the morning, Rear Admiral Harry Hill’s task group put ashore the reconnaissance company of V Amphibious Corps there, followed by the 2nd Battalion, 106th Infantry Regiment, of the 27th Infantry Division. Reconnaissance revealed that the Japanese had withdrawn their small garrison from the atoll back in 1943; according to American accounts, only a single Japanese naval petty officer remained on the islands, and he was taken prisoner. Majuro was occupied without loss. Its spacious lagoon soon became the main anchorage of the American fleet in the central Pacific, and an airfield was built on one of the islands.

The same day at Kwajalein atoll, soldiers of both divisions took the islets lying next to the main objectives, designated in the plans by code names from the phonetic alphabet. In the north, units of the 25th Marine Regiment seized the islets named Ivan, Jacob, Albert, Allen and Abraham, which surround Roi-Namur; it was the first time Marines had set foot on territory that Japan had held before the war. In the south, units of the 7th Infantry Division took the islets of Carlos, Carter, Cecil and Carlson near Kwajalein Island. The Japanese posts on them were small, and resistance – though fierce in places – was quickly broken. By evening batteries of field artillery were already in position on the islets, and throughout the night they shelled the main islands together with the ships. Several howitzer battalions were landed on the southern islets, including heavy 155 mm howitzers emplaced on Carlson islet, within range of the whole of Kwajalein Island.

Not everything went smoothly on the first day. Strong wind and swell delayed and scattered the waves of amtracs, and inexperienced crews, particularly in the 4th Marine Division, lost their bearings and assembled in disorder. The same problems were to recur the next day at Roi-Namur. According to the American official history, however, losses on the first day were small compared with Tarawa.

The assault on Roi-Namur and Kwajalein

The main landing took place on 1 February. In the north the 23rd and 24th Marine Regiments landed from the lagoon side on the twin islands of Roi and Namur, linked by a causeway and a sandspit. Roi, almost entirely taken up by an airfield, was captured the same day. On Namur, densely built up with storehouses and shelters, the fighting went on until 2 February. It was there that the most tragic accident of the operation occurred: Marines threw an explosive charge into a concrete bunker, unaware that it was being used to store torpedo warheads and bombs. According to American figures, the explosion, which sent up a column of smoke visible from distant ships, killed about 20 Marines and wounded more than a hundred.

In the south the 7th Infantry Division landed at 9.30 a.m. on 1 February on the western tip of Kwajalein Island, about four kilometres long and a few hundred metres wide. The Japanese, convinced before Tarawa that the Americans would not cross the reef on the lagoon side, had placed their strongest fortifications on the ocean shore, and their defensive line lacked depth. The Army troops advanced methodically, clearing bunker after bunker and beating off night counter-attacks; the island was declared secure on 4 February. Rear Admiral Akiyama was killed in the fighting. At the same time the neighbouring islands of the atoll were occupied, including Ebeye.

According to figures cited from studies based on the American official history, the capture of Kwajalein atoll cost the Americans – depending on the method of counting – from more than 330 to nearly 500 killed and about 1,300–1,500 wounded. The Japanese garrison was almost entirely wiped out: of about 8,000 defenders, some 250 men were taken prisoner, many of them Korean labourers. Of the roughly 3,000 men on Roi-Namur, according to the most frequently cited figures, only a few dozen survived.

Significance

Kwajalein proved the opposite of Tarawa: an island defended by a similar number of men was taken at a fraction of the cost. This confirmed the soundness of the changes introduced after the November assault – the prolonged bombardment, the mass use of amtracs and the artillery on neighbouring islets. Success came so quickly that the unused reserves could be sent straight on: as early as 17 February the Americans landed on Eniwetok atoll on the western edge of the archipelago – several months earlier than planned – and on 17–18 February Mitscher’s carriers inflicted heavy losses on the Japanese base at Truk atoll in the Carolines, regarded as the “Gibraltar of the Pacific”. The bypassed atolls of Wotje, Maloelap, Mili and Jaluit remained in Japanese hands until the end of the war, cut off, bombed and stricken by hunger.

For the Japanese, the loss of the Marshall Islands meant the breaching of their outer defensive ring, and it led them to draw conclusions that would later cost the Americans dearly: instead of defending the beaches, the defenders of the Marianas, Peleliu and Iwo Jima were to fight inland, in systems of caves and fortifications. Kwajalein, Majuro and Eniwetok, meanwhile, became bases from which the American fleet set out for the Marianas in June 1944. After the war the Marshall Islands remained under United States administration as a UN trust territory; nuclear tests were carried out at Bikini and Eniwetok atolls, and Kwajalein is still an American missile test range today.