This was the US seizure of Betio islet, the main Japanese position of the Tarawa atoll, as part of the ‘Galvanic’ seizure of the Gilbert islands group (20/23 November 1943).
‘Galvanic’ was the first step in the drive across the central Pacific by the US forces controlled by Admiral Chester W. Nimitz’s Pacific Ocean Areas command between 20 and 28 November 1943.
During the first nine months of 1943, recruitment, training and industrial expansion had paved the way for a huge expansion of the US available for Pacific operations, and in order to use these land, sea and air assets the planners of the Joint Strategic Committee (the long-range planning arm of the Joint Chiefs-of-Staff) decided not merely to reinforce the current efforts of Admiral William F. Halsey’s South Pacific Area and General Douglas MacArthur’s South-West Pacific Area, but to implement a new offensive campaign through the central Pacific to offer a supplement or indeed alternative to the existing drive.
The Joint Strategic Committee therefore envisaged a five-phase grand strategic effort against Japan: in the first, simultaneous advances would be made by MacArthur’s and Nimitz’s forces, of which the latter would have the greater resources; in the second, the Philippine islands group would be recaptured; in the third, a major lodgement would be secured on the Chinese coast; in the fourth, Hong Kong would be recaptured; and in the fifth, a strategic bombing campaign would be launched against the Japanese home islands. In May 1943 the Joint Strategic Committee became the Joint War Plans Committee, and this added a sixth phase envisaging an invasion of the Japanese home islands.
This overall scheme was accepted by the US authorities on 8 May, and secured inter-Allied approval at the ‘Trident’ second inter-Allied conference held in Washington during May 1943. MacArthur objected strongly to the plan, but on 20 July Nimitz was ordered to proceed with a central Pacific campaign in which the first target would not be the Marshall islands group as originally intended, but rather the Gilbert islands group.
The Marshall islands group comprises two parallel chains of atolls extending some 800 miles (1300 km) from southeast to northwest. They lie 2200 miles (3500 km) to the south-west of Hawaii and in 1941 accommodated the easternmost Japanese bases. As a result, Kimmel’s attention was riveted on this island group as war approached, rather than to the north, from which the Pearl Harbor attack would come.
The Marshall islands group includes numerous excellent anchorages, but a land area of only 70 sq miles (181 km²) with an average elevation of just 7 ft (2.1 m) with a maximum elevation of 34 ft (10.4 m). Despite the group’s miniscule land area, the Japanese had built a handful of airfields. In 1935 the islands' population was about 10,000 members of the native peoples, and 490 Japanese.
Japan had seized the Marshall islands group from Germany during World War II, and retained control after the war under a League of Nations' mandate. When Japan withdrew from the League of Nations, it retained de facto control of the islands and refused to allow foreigners to visit the area, which led to rumours that the islands had been heavily fortified, but in fact nothing but airfields and seaplane ramps had been constructed before December 1941. The Japanese could not come to a decision whether to make the Marshall islands group part of their outer line of defence or to abandon the group and concentrate on fortifying the Mariana islands Group. As a result, neither was adequately fortified when the US offensive swept to the west across the central Pacific.
The administrative centre of the Marshall islands group was at Kwajalein, but there were also significant facilities at Maloelap, Wotje, and Jaluit.
The Gilbert islands group is a chain of atolls lying some 2,500 miles (4025 km) to the south-west of the Hawaiian islands group and just to the north of the equator. The chain contains some hundreds of islands, all of them small, within a total land area of just 166 sq miles (430 km²). The chain is about 500 miles (805 km) long and lies about 300 miles (485 km) to the south-east of the Marshall islands group and just to the north-east of the Ellice islands group. In 1941 the islands had a population of about 28,000 persons, primarily Micronesian with less than 100 Europeans. However, the tiny land area meant the islands had the highest population density of any in the Pacific.
The islands were under British control in 1941. The population enjoyed a high degree of self-rule, and British law prohibited land purchases by non-natives. British oversight was exercised through a resident commissioner at Ocean Island who also oversaw the Ellice, Phoenix, Fanning and other small island groups in the area.
There are 16 main atolls in the chain, none of which have elevations much greater than 12 ft (4 m) and consist of coral bedrock overlaid by sand and some poor soil. These support some scrub and coconut palms. The island were relatively healthy for westerners, with little incidence of malaria or other tropical diseases, and the climate is uniformly warm and wet.
The local infrastructure was limited to a lagoon-side road on each atoll and a few piers for ocean-going vessels. There were no airfields in the group before the arrival of the Japanese. This took place of 8 December 1941 when elements of the 51st Guard Force occupied Makin atoll and soon began to develop a seaplane base and radio station. The nearby atolls were visited sporadically by Japanese detachments, which rounded up Allied coast watchers and European civilians: the civilians were interned while the coast watchers were eventually murdered.
Following the Makin raid of August 1942, the Japanese reinforced their garrisons and began to fortify Tarawa atoll, on which they also constructed an airfield.
So far as Nimitz’s central Pacific forces were concerned, the key factor about the Marshall islands group was that it lay beyond the range of current US land-based aircraft, while the Gilbert islands group could be effectively reconnoitred by US land-based aircraft, which could also support the landings.
This was to be the first time in the war that the US forces faced serious Japanese opposition to an amphibious assault. The strategic rationale of the operation was based on the US planners’ decision to establish on the Mariana islands group a number of forward air bases capable of supporting operations across the mid-Pacific, the Philippine islands group, and into Japan itself. The Mariana islands group was heavily defended, however, and in order for any assault on them to succeed, it was thought that land-based bombers would have to be used to ‘soften’ the defences. The nearest islands capable of supporting such an effort were the Marshall islands group, to the north-west of Guadalcanal in the Solomon islands group. Taking the Marshall islands group would provide the base needed to launch an offensive against the Mariana islands group, but the Marshall islands group was isolated from direct communications with the Hawaiian islands group by the Japanese garrison and its airfield on the small island of Betio, on the western side of Tarawa atoll in the Gilbert islands group, the wide-flung group of atolls along the edge of the defensive perimeter which the Japanese had established by July 1942.
Thus, in order to pave the way for an eventual invasion of the Mariana islands group, the battle had to start far to the east at Tarawa atoll.
The Japanese were fully conscious of the Gilbert islands group’s strategic location, however, and had invested considerable resources in the fortification of Tarawa, with particular emphasis on the defence of Betio, the atoll’s largest island.
Tarawa atoll is triangular in shape, with the eastern side 18 miles (29 km) long and the southern side 12 miles (19 km) long. The atoll comprises a large number of islets, of which the most important was Betio at the atoll’s south-western tip. All the islets were planted with coconut palms. The western side of the triangle is barrier reef with a single deep pass 1 mile (1.6 km) wide.
Betio extends basically on an east/west axis, with a length of about 3,800 yards (3475 m) and a width of about 600 yards (550 m), for an area if about 291 acres (118 hectares). No point on the island rises to more than 10 ft (3 m) above sea level, and the only water supply in 1943 was was provided by catchment basins and a few brackish wells. The island is surrounded by a reef between 500 and 1,200 yards (460 and 1095 m) wide, and a sea wall surrounded most of the island at about the high-tide mark. The long Government Pier extended 535 yards (165 m) across the reef on the northern, or lagoon, side of the island to allow ocean-going ships to berth in the safer waters of the Tarawa atoll’s . A shorter pier, the 50-yard (46-m) Burns Philp Pier, was located 400 yards (365 ms) to the east of Government Pier and was accessible only to small boats.
A small Japanese force landed on the atoll on 10 December 1941, rounded up a few Europeans and withdrew. A permanent garrison did not arrive until 15 September 1942. The Japanese subsequently constructed an air base on Betio, with a 4,400-ft (1340-m) runway and taxiways. The islet’s native population was relocated to others of the atoll’s islets, where they were expected to fish for the Japanese as well as themselves and provide occasional labour details to work on the defences.
The islet’s garrison was Rear Admiral Shibasaki Keiji’s Gilberts Area Defence Force, which was centred on the 2,619 naval troops of Commander Takeo Sugai’s 7th Sasebo Special Naval Landing Force, an elite unit which also included 14 Type 95 light tanks under the command of Ensign Ohtani. In order to bolster the defence, the 1,247 men of the 111th Pioneer Regiment and 970 men of Vice Admiral Masami Kobayashi’s 4th Fleet Construction Unit were also delivered to the island: about 1,200 of the men in these two groups were Koreans. Some 14 coast-defence guns were emplaced round the island in concrete bunkers: the guns included four 8-in (203-mm) British weapons once believed to have been taken from the erstwhile defences of Singapore where there were, in fact, no such weapons, but it was later ascertained that these weapons had been part of an order for weapons of this calibre placed by Japan in 1905. About 500 pillboxes, ‘stockades’ build from palm logs, and 40 pieces of artillery were also scattered around the island, and an airfield was cut into the brush along the island’s highest portion. Trenches connected all points of the island, allowing troops to move under cover to all the points at which they were needed.
Ammunition supplies were somewhat limited, at 4,800 rounds of 75-mm (2.95-in) and 127-mm (5-in) anti-aircraft ammunition and only 15,000 rounds of 13-mm (0.521-in) heavy machine gun ammunition.
The Tarawa atoll’s lagoon lies to the north and east of Betio, and the islet’s entire north coast is in the shallow waters of the atoll’s lagoon, and the southern and western sides in deeper water. An attack would almost certainly have to approach from the lagoon as the deeper water in the south offered no reasonable landing areas. In order to prevent this, a long wall was constructed across the lagoon just in from the high water mark, behind which a series of pillboxes and machine gun positions could engage anyone trying to get over the wall.
The US resources for ‘Galvanic’ were first concentrated at Pearl Harbor and elsewhere in the Hawaiian islands group before being despatched to forward bases in places such as the Fiji and New Hebrides island groups for final training.
The organisation for massive offensive moves over considerable distances, including ‘Galvanic’, had been readied in the form of Vice Admiral Raymond A. Spruance’s new 5th Fleet (seven battleships, eight aircraft carriers under the command of Rear Admiral Charles A. Pownall, seven heavy and three light cruisers, and some 34 destroyers), Rear Admiral Richmond K. Turner’s 5th Amphibious Force, Major General Holland M. Smith’s V Amphibious Corps (100,000 men), and Rear Admiral John E. Hoover’s land-based air assets of the three US forces including, in the Ellice islands group, the growing strength of Major General Willis H. Hale’s 7th AAF. Many of the naval and marine assets had previously been Halsey’s 3rd Fleet for operations in the Solomon islands group.
The ‘Galvanic’ operation was schemed by Turner and Julian Smith as a two-part undertaking, with a Northern Attack Force under Turner to tackle Makin and a Southern Attack Force under Hill to take Tarawa in ‘Longsuit’. In preparation for ‘Galvanic’, Pownall’s Task Group 50.1 1 attacked Mili; Rear Admiral Arthur W. Radford’s TG50.2 2 attacked Makin; Rear Admiral Alfred E. Montgomery’s TG50.3 3 attacked Tarawa; and Rear Admiral Forrest P. Sherman’s TG50.4 4 attacked Nauru.
The US reconnaissance effort before 'Longsuit' was both thorough and successful, and established that the Japanese defences were oriented toward the islet’s southern and western beaches. It was decided, therefore, that the landing would be delivered on the islet’s lagoon side. However, the reefs here extend 300 to 500 yards (275 to 460 m) offshore, and there was concern about whether or not the full tide would provide water deep enough to allow landing craft to cross. Tides in this part of the Pacific are frequently erratic, and in 1944 there were no tide tables for the area. As a result the planners consulted former British residents of the atoll and concluded that there was a 67% chance of favourable tides on the proposed invasion date. Delaying the invasion meant a risk of a resurgence of westerly winds, which would make the invasion impossible, so Turner decided to take the chance offered by the probably tide.
US intelligence had confirmed that Makin was by far the softer of the two objectives, but the command team opted to capture Makin first as any Japanese riposte (by air from the Mariana islands group or by sea from the base of Admiral Mineichi Koga’s Combined Fleet at Truk atoll in the Caroline islands group) would stage through Makin. The islet was an easy target, as it was held by only 300 troops, 100 aviation personnel and 400 labourers, and was reduced in four methodical but uncomplicated days between 20 and 23 November.
On the same day as Makin was attacked, substantially larger US forces launched ‘Longsuit’ against the altogether stronger defences of Tarawa, which was therefore an altogether tougher nut for the Southern Attack Force built round Major General Julian C. Smith’s 2nd Marine Division supported by Hill’s force of five escort carriers, three battleships, three heavy cruisers and 21 destroyers covered at longer range by the four fast aircraft carriers of Pownall’s task force.
This US invasion force was the largest yet put together for a single operation of the Pacific war, and in overall terms comprised 17 aircraft carriers (six fleet carriers, five light carriers and six escort carriers), 12 battleships, 12 cruisers (eight heavy and four light), 66 destroyers and 36 transports, as well as the ground force of some 35,000 men provided by the 2nd Marine Division and part of Major General Ralph C. Smith’s 27th Division. Rear Admiral Harry W. Hill’s Task Force 53 comprised 12 troop transports, three supply transports and one dock landing ship to deliver and land 18,600 men of the 2nd Marine Division on Betio.
Escort was provided by the destroyers John Rodgers, Sigsbee, Heermann, Hazelwood, Harrison, McKee and Murray, and fire support by Rear Admiral Howard F. Kingman’s Task Group 53.4 with the battleships Tennessee, Maryland and Colorado, heavy cruisers Indianapolis and Portland, light cruisers Mobile and Santa Fe, and destroyers Bailey, Frazier, Gansevoort, Meade, Anderson, Russell, Ringgold, Dashiell and Schroeder.
Air support came from Rear Admiral Van H. Ragsdale’s TG53.6 with the escort carriers Suwanee, Chenango, Barnes and Nassau, and destroyers Aylwin, Farragut, Monaghan, Cotten, Cowell and Bancroft.
Led by the minesweepers Pursuit and Requisite, and supported by the destroyers Ringgold and Dashiell, the first assault waves landed on the lagoon side of Betio. Julian Smith had planned to land artillery on Bairiki islet to cover the main landing, but Holland Smith insisted on holding the 6th Marine Regiment in reserve, forcing Julian Smith to commit his two remaining regiments to the direct frontal assault. On the other hand, Holland Smith had a major dispute with Turner for an increased allotment of LVT Landing Vehicles, Tracked, to lift the marines over the fringing reef in case the tides proved unfavourable. Although the number allocated was still insufficient, and most of the marines would still have to reach the shore in conventional landing craft, the increased allotment of LVTs was to prove crucial in the ensuing battle.
Before the landing was committed, the naval forces opened fire on 20 November in a 90-minute bombardment interrupted only for the brief intervals in which dive-bombers from the carriers undertook pinpoint attacks against the Japanese fixed positions. Most of the larger Japanese guns were knocked out during this period. The island is at most points only a few hundred yards wide, and the bombardment turned much of it into a cratered wilderness. By the time of the landing, it was thought that no one would be left to defend what was left of the tiny islet, which had received something in the order of 3,000 tons of shells.
When they began on 20 November, the landings immediately ran into trouble, initially as Turner had lost his gamble on the tide, and as a result many landing craft were stranded on the reef by an unusually low tide, leaving their troops to wade ashore under a hail of devastating fire from the defenders. Moreover, though many of the US naval commanders (but only a minority of marine commanders) believed that their preliminary bombardment would have left little but a few shocked survivors to be mopped up, this proved wholly optimistic and most of the Japanese fortifications were still intact. Then the 3,500 of the 5,000 men committed on the first day who actually reached the shore found themselves pinned on the beaches by intense machine gun and small arms fire.
Not all the bad luck descended on the Americans, however, for Keiji was killed by artillery fire early in the battle, and the commander’s death, in combination with the disruption of the islet’s communications network from the bombardment, meant that no Japanese counterattack could be organised while the US landing forces were at their most vulnerable.
In greater details, the attack was planned as assaults across three major beaches along the islet’s north coast (Red 1 on the bay on the western end of the islet’s shore, Red 2 between this and the Government Pier, and Red 3 to the east of the Government Pier). There were also two other beaches (Green on the western end of the islet and Black on its southern shore), but these were not thought suitable for any initial landings. The airstrip, running roughly east/west, divided the island into northern and southern sections. With the 2nd Marines moving against Red 1 and Red 2, and two battalions of the 8th Marines against Red 3, the men of the three assault battalions under the command of Colonel David M. Shoup of the 2nd Marines reached the shore without undue difficulty in their LVTs, these battalions then being checked after moving inland less than 100 yards (90 m). This made it more difficult for the following battalions, which were carried in LCVP Landing Craft, Vehicle and Personnel, and became stuck on the reef, leaving the men with the task of wading about 700 yards (640 m) to the shore through a hail of Japanese fire.
The marines started their attack on the lagoon at 09.00, later than expected, and many of the men found themselves stuck on the offshore reef while the Japanese, having hidden in deep shelters during the bombardment, now quickly manned their guns as the naval bombardment was lifted to allow the marines to unload. Japanese fire from the island soon started, and the boats caught on the reef were soon burning. Troops jumped out and started making their way ashore under machine gun fire the entire time. Only small numbers of TVT amtracks (amphibious tractors) were available, and these were able to climb over the reef, with some difficultly, and then start to approach the beach, but many of the vehicles were knocked out by larger guns as they climbed over, and half were out of action by the end of the day.
The first assault wave was able to land only a few men, and these were instantly pinned down under the log wall along the beach. Several early attempts to land tanks and to break through the wall failed when the relevant landing craft were hit on the run to the shore, and either sank or had to withdraw while taking on water. Two tanks were finally landed on the eastern end of the beach, but were then knocked out fairly quickly. Three tanks managed to land on the western end and helped push the advance to a point some 300 yards (275 m) inland, but then one of these tanks fell into a shell hole, and another was destroyed by a mine. The remaining tank was used as a mobile machine gun pillbox for the rest of the day. A third platoon was able to land all four of its tanks on Red 3 at about 12.00 and operate successfully for much of the day, but by the end of the day this unit was also down to a single tank.
Keiji was killed by artillery fire early in the battle, and the death of the Japanese commander, together with the disruption of the islet’s communications network in the naval bombardment, meant that the Japanese could not organise any counterattack while the US forces were still vulnerable.
By 12.00 the marines had taken the beach as far as the first line of Japanese defences. By 15.30 the line had moved inland in places, but was still generally along the first line of defences. The arrival of the tanks started the line moving on Red 3 and the end of Red 2, and by the fall of night the US line was about half-way across the island, only a short distance from the main runway. During the later hours the Japanese defenders continued their harassing fire: in one instance, a Japanese marine swam out to one of the disabled LVTs and brought its 0.5-in (12.7-mm) machine gun into action into the rear of the marines’ lines. By the time the US forces retook the amtrack, several men had been injured or killed.
With the marines holding a line on the island, the second day of 'Longsuit' developed into an effort to split the Japanese defence by expanding the bulge near the airfield until it reached the south shore. Meanwhile the forces on Red 1 were instructed to secure Green beach, which comprised the entire western end of the island. In the end, the seizure of Green beach proved to be somewhat easier than expected. With heavy resistance all through the area, the commander decided to avoid direct combat, and instead called in a naval bombardment. Inching their way forward during the day, the artillery spotters were able to organise the destruction of the machine gun posts and remaining defences on a one-by-one basis. After the naval fire had ceased, the marines were able to take the positions in about an hour and with few losses.
Operations along Red 2 and Red 3 beaches were considerably more difficult. During the night the Japanese defenders had set up several new machine gun posts between the closest approach of the forces from the two beaches, and cut them off from each other for some time. By 12.00 the US forces had brought up their own heavy machine guns, and the Japanese positions were knocked out of action. By a time early in the afternoon the marines had managed to cross the airstrip and occupy abandoned defensive works on the airstrip’s southern side.
At about 13.00 a message arrived that some of the defenders were making their way across the sandbars from the extreme eastern end of Betio to Bairiki, the next islet to the west of Betio. Elements of the 6th Marines were then ordered to land on Bairiki to seal this line of retreat. The marines formed, with tanks and pack artillery, and were able to start their landings at 16.55. They came under machine gun fire, so warplanes were committed to locate the guns and suppress them. The force landed in the face of no further fire, and it was later found that only a single pillbox with 12 machine guns had been set up by the forces which had been assumed to be escaping. The occupants had a small tank of petrol in their pillbox, and when it was hit in an air attack all the men in the pillbox were burned to death.
Meanwhile two battalions of the 6th Marines landed on the northern end of Green beach, adjacent to Red 1 beach.
The situation as a whole was not much better for the Americans at the end of the second day than it had been 24 hours earlier. The entire western end of the islet was now under US control, as too was a fairly continuous line between Red 2 and Red 3 beaches around the airfield taxiways. A separate group had moved across the airfield and set up a perimeter on the southern side, up against Black 2 beach. These groups were not in contact with each other, with a gap of more than 500 yards (460 m) between the forces at Red 1/Green beaches and Red 2 beach, and the lines on the northern side inland from Red 2 and Red 3 beaches were not continuous.
Nevertheless, it can be seen in retrospect that at this point the marines began to gain the upper hand.
In the fighting of the third day, the marines devoted themselves largely to the consolidation of existing lines, and the delivery to the shore of additional heavy equipment and tanks. During the morning the forces originally landed on Red 1 beach made some progress toward Red 2 beach, but at some cost. Meanwhile the units of the 6th Marines landed on Green beach to the south of Red 1 beach formed as the 6th Marines' remaining battalion came ashore.
By the afternoon the 1/6th Marines was sufficiently organised and equipped to move onto the offensive. At 12.30 the battalion started off, and was soon pursuing the Japanese forces along the island’s south coast. By a time late in the afternoon the battalion had reached the eastern end of the airfield, and formed a continuous line with the forces which had landed on Red 3 beach two days earlier.
By the evening the US forces clearly had the advantage. The remaining Japanese forces had either been compressed into the tiny area of land to the east of the airstrip, or been pinned in several pockets near Red 1 and Red 2 beaches, or near the eastern edge of the airstrip. Realising this, the Japanese forces prepared for a counterattack, which started at about 19.30. Within this, small units were sent in to infiltrate the US lines in preparation for a full-scale assault, but were beaten off by concentrated artillery fire and the main assault did not take place. Another attempt was made at 23.00, and in fact gained some ground. At 04.00 on 24 November the expected assault finally took place, in the location of the earlier probe at 23.00 earlier in the same night. About 60 minutes later, after the end of the battle, 200 of the 300 Japanese involved were found dead in front of the US lines, the vast majority the victims of artillery fire.
By this point the Japanese had little left with which to defend the island. When combat resumed during the next morning, the US forces had little trouble forming up. The Japanese pockets remaining in the western end had been eliminated by 12.00, while the men of the 6th Marines continued their advance and reached the eastern tip of the island just after 13.00. A pocket remained near the eastern end of the runway until the afternoon. The battle was essentially over by sunset, with the entirety of the island now covered by a single continuous line. Nevertheless, small numbers of individual Japanese soldiers still came out of hiding during the night to continue the fight.
Over the next several days the 2/6th Marines landed on Bairiki, and moved along the atoll’s other islets to clean up, taking Buariki and Naa on 27 and 28 November respectivley. The campaign was completed by the seizure of Apamama, to the south of the main atoll, against the negligible resistance of a detachment of the 3rd Special Base Force by the V Amphibious Corps Reconnaissance Company.
Portions of the 2nd Marine Division started leaving soon after this, and the last elements had been pulled out by a time early in 1944. Of the 18,600 men available to the 2nd Marine Division on 20 November, 990 had been killed and 2,391 wounded, while the Japanese survivors amounted to one officer and 16 men, plus 129 Korean labourers, and the total Japanese and Korean casualties were therefore 4,752, including 1,169 Korean labourers, killed in action.
The heavy US casualty level sparked off a storm of protest in the USA, where the high losses could not be understood for such a tiny and apparently unimportant island.
With 'Longsuit' completed, US engineering detachments arrived to undertake the development of the airfield, which was declared operational on 18 December 1943. By 1 January 1944 the airfield boasted two runways each 6,600 ft (2010 m) long, and a new 6,000-ft (1830-m) runway had been constructed on Buota islet. These airfields proved invaluable as staging points for bomber raids on the Japanese positions in the Marshall islands group before the launch of 'Cataract'.