Japanese interest in the Gilberts dated from the earliest days of the war. The primary strategic purpose of the empire at the beginning of the war was the occupation and development of what was called the Southern Resources Area—the Netherlands Indies and adjacent regions. It was this part of the Pacific that contained most of the raw materials considered essential to Japan’s economic welfare and military potential. As a corollary to the seizure of these islands, it was also believed necessary to maintain free lines of communication between the Japanese homeland and the Southern Resources Area. Finally, to guarantee the permanent success of its ventures, Japan hoped to cripple Allied naval strength in the Pacific and establish a strong defensive perimeter to protect the homeland and its new economic adjunct to the south. To accomplish these objectives, Japanese strategists contemplated three successive steps: the establishment of a perimeter along a line from the Kurils through the Marshalls, the Bismarck’s, Timor, Java, Sumatra, and Malaya to Burma; the consolidation and strengthening of this perimeter; and the defense of the perimeter.
The responsibility for carrying out this plan in the Central Pacific and in the Bismarck’s area fell to the 4th Fleet, which before Pearl Harbor commanded naval ground force garrisons in the mandated islands from its headquarters at Truk. According to Imperial Navy plans formulated in November 1941, the mission of the 4th Fleet at the beginning of the war was:
- Defend the South Sea Islands, patrol, maintain surface communications, capture Wake. At opportune time attack and destroy enemy advanced bases in South Pacific Area. In co-operation with Army capture Guam and then Bismarck Area.
- Defend and patrol points in South Sea Islands and Bismarck’s. Maintain surface communications. Search for and attack enemy shipping. Make surprise attacks and destroy enemy bases on our perimeter.
The main offensive thrust was to reach southward to the Bismarck’s area, while in the east the perimeter was to be held and strengthened by the capture of Wake. A minor part of this plan was the seizure of Makin Atoll in the Gilberts in order better to protect the more important Marshall Islands to the north. Makin, lying 0°40′ east of the boundary of the Japanese Mandate, offered the advantage of being located about 240 nautical miles southeast of Jaluit, the most important seaplane base in the lower Marshalls. The seizure of Makin and its subsequent development into a seaplane base would make it possible to extend air patrols closer to Howland, Baker, and the Ellice Islands and to protect the eastern flank of the Japanese perimeter from possible Allied advance through the Ellice-Gilberts chain. Also, since Makin was the northernmost of the Gilberts, it could be the most easily supplied by transport from the Marshall Islands.
On 3 December 1941 one company was detached from the 51st Guard Force based on Jaluit and constituted the Gilberts Invasion Special Landing Force under Air Force command. This force, consisting of from 200 to 300 troops plus laborers, left Jaluit by ship on 8 December and on the 10th reached Makin Atoll, which was forthwith occupied. One of the troopships also visited Tarawa on 24 December. The entire operation yielded nine prisoners.
[NOTE GM-4A: The 51st Guard Force was part of the 6th Base Force, which was under command of 4th Fleet. Base Forces, Guard Forces and Defense Forces (Konkyochitai, Keibitai, Bobitai), Vol. 1, Dec 41-May 42, in U.S. National Archives, World War II Seized Enemy Records, Record Group 242, NA 12029, WDC 161090; 6th Base Force War Diary (Dairoku konkyochitai senji nisshi), NA 12654, WDC 160599. Hereafter documents contained in the National Archives collection will be cited by title, National Archives (NA) number, and Washington Document Center (WDC) number.]
After the invasion the Makin garrison set about constructing a seaplane base and coastal defenses. By August of 1942 the garrison had dwindled to only 43 men under a warrant officer, and it was this tiny group that was called upon to defend the atoll against the first American landing in the Central Pacific.
Carlson’s Raid and Its Aftermath
On 17 August 1942 the 2nd Marine Raider Battalion, consisting of 221 marines under the command of Colonel Carlson, landed on Makin from two submarines. The primary purpose of this raid was to confuse the Japanese and cause them to divert forces that might otherwise be assigned to the Guadalcanal area. Carlson himself stated the secondary purposes of the raid: This task group will execute landings on Makin from the USS NAUTILUS and USS ARGONAUT on 17 August for the purpose of destroying enemy troops and vital installations and to capture important documents and prisoners.
In the early hours of 17 August the raiders disembarked from the two submarines into rubber boats powered by outboard motors and landed on the southern coast of Butaritari. Heavy swells and mechanical failures in some of the engines prevented the party from making two separate landings as originally planned, but eventually fifteen out of the eighteen boats managed to get ashore at one landing beach, while two others landed a mile north and another a mile south.
[NOTE CR-88K: This account of Carlson’s raid is taken from the following sources: CO 2nd Marine Raider Bn, Rpt of the Raid Against Makin, 17-18 Aug 42, dated 3 Sep 42; Ltr cited n. 6; Ltr, CTG 7.15 (USS Nautilus) to CTF 7, sub: Rpt of Marine-Submarine Raider Expedition. All of these reports are on file at Headquarters, USMC Historical Division.]
Just after the landing one of the marines accidentally discharged his rifle. Believing that all chance of surprise was lost, Colonel Carlson ordered Company A of his battalion to proceed across the island to the lagoon shore. By 0545 the company commander, Captain Merwin C. Plumley, USMC, reported that he had captured Government House without opposition, and he was then ordered west along the lagoon road. By this time it had become apparent that the Japanese defenses were concentrated at the base of On Chong’s Wharf on the lagoon shore and at Ukiangong Point, the southwestern most promontory of Butaritari. Carlson asked for naval gunfire in this area, and Nautilus complied by firing some twenty-four rounds. Throughout the day isolated groups of Japanese were encountered, spirited fire fights ensued, and a number of enemy were killed. The chief Japanese response to the landing was from the air.
At 1130, two Japanese naval reconnaissance planes scouted the island, dropped two bombs and then flew back north to a base in the Marshalls. About two hours later, twelve enemy planes arrived and bombed and strafed for an hour and a quarter. Two of the planes landed in the lagoon and were destroyed by Marine machine gun and antitank rifle fire. The third and last air raid occurred at 1630.
Shortly thereafter, at 1700, the marines began an orderly withdrawal to the southern coast, and within two hours the bulk of the battalion was boated, but only a few were able to get through the heavy surf and back to the submarines. A hundred and twenty men were left on the beach that night. By the following morning still more marines made their way through the surf, but at 0920 further evacuation was halted by an air raid, leaving seventy men, including Colonel Carlson, stranded on the beach.
At this point, the battalion commander discovered that Japanese resistance was practically nonexistent, consisting of only a few troops scattered about the island. He sent out patrols to search for food and destroy the Japanese radio station at the base of On Chong’s Wharf. A cache of aviation gasoline of 700 to 1,000 barrels was fired, and the marines ranged freely about the island, meeting only the most feeble resistance. The office of the Japanese commandant was searched and all available papers secured. Finally, on the evening of the second day, evacuation was completed and all of the rubber boats reached the Nautilus.
This expedition cost the lives of thirty marines. Left ashore were twenty-one dead and nine others who were later captured and beheaded. In retrospect, the entire expedition appears to have been ill advised. Though little of any importance was learned and no subsequent attempt was ever made in the Pacific war to emulate the Makin raid, the observations of Major Roosevelt, who was Carlson’s executive officer, were later of some value to the intelligence staff of the 27th Infantry Division in preparing plans for the ultimate invasion of Makin. Otherwise, there is no evidence that the raid of August 1942 made any significant contribution to Allied victory in the Pacific.
On the other hand, there is every reason to believe that this raid induced the Japanese to commit to the Gilberts far heavier forces than they had originally contemplated. To that extent the progress of American arms across the Central Pacific was made more difficult. The Japanese response to Carlson’s expedition was immediate.
Troops were drawn from the Marshalls, the Caroline’s, and Japan and sent to garrison hitherto-unoccupied islands in the British Mandates. The Gilberts now were occupied in force, and garrisons were established as well on Nauru and Ocean Islands. Before August, in all the islands south of the Marshalls the enemy had only the small force on Makin. After August they began a build-up in this area that was to result in several island strongholds under an entirely new base force command. Even if it cannot be proved conclusively that Carlson’s expedition was the sole cause of this change in policy, the raid can with certainty be credited with a rapid acceleration in the Japanese program of building up defenses in the Gilberts.
No time was lost in replacing the Makin garrison. On 19 August, four reconnaissance seaplanes from Kwajalein made a close search of the Makin area and found no trace of the Americans. This indicated that the coast was clear for a counter-landing, in full company strength, which the Japanese had started to organize at Jaluit as soon as news of the raid was received. On the 20th a small advance detachment was flown to Makin from Jaluit and was shortly followed by the bulk of the force transported by ship. The nine marines left on Butaritari were taken prisoner and the equipment that Carlson was forced to abandon was captured.
Now began a series of small troop movements from all directions into the fringe of British island possessions bordering the Marshalls. Nauru was invaded on 25 August and Ocean Island on the 26th. On the 29th a landing force composed of one company of the 43rd Guard Force (western Caroline’s) took over Nauru. Two days earlier a company detached from the 62nd Guard Force (Jaluit) commenced to garrison Ocean. This unit was joined a few days later by a company from the 41st Guard Force from Truk. Another company, from the 5th Special Base Force, left Saipan on 28 August and on the 30th arrived at Makin, where it was to remain pending the arrival of a special naval landing force from the Japanese homeland.
These moves were followed by the invasion of Apamama, which lasted from 31 August to 4 September. More important still, the entire Yokosuka 6th Special Naval Landing Force (SNLF) was dispatched from Japan to the Gilberts in September. This force consisted of 1,509 officers and men and was the first unit of any considerable size to arrive in the area. It was these troops that were to remain in the Gilberts, chiefly on Tarawa, until the American invasion in November 1943. On 15 September the main portion of the 6th SNLF arrived at Tarawa, and detachments were subsequently transferred to Apamama and Makin.
In September and October small parties were sent from Tarawa to snuff out the few remaining communications centers maintained by the Allies in the area. Since the beginning of the war a number of Australian and New Zealand coast-watchers had stayed in various islands of the central and southern Gilberts, observing Japanese air and surface movements and radioing important information to the Allies. These the Japanese now proceeded to eliminate quickly. On 26 September a small party landed on Beru Atoll and destroyed a British wireless station there. Next day Tamana Atoll was invaded. Here the Japanese destroyed communications equipment and captured two Allied soldiers and one wireless operator. Also on the 27th, a second landing party captured communications equipment on Maiana, Nonouti, and Kuria Atolls. Later, in October, Maiana and Nonouti were revisited and Abaiang and Beru raided, netting more wireless sets and a few prisoners. By 6 October the Japanese declared that the Gilberts were completely cleared of enemy personnel, and that all communications installations had been destroyed.
Thus the Makin raid of August 1942 constitutes a clear line of demarcation in Japanese policy in the Gilberts. Before that time there were only forty-three men, under command of a warrant officer, stationed in the whole area. Within a month after Carlson’s battalion landed on Makin, the total garrison for the Gilberts came to more than 1,500 troops plus four companies on Nauru and Ocean. Just as significant was the change in the command structure for the area. Before August 1942 the only command located in the Gilberts was the Special Landing Force at Makin. This force was subordinate to the 62nd Guard Force based on Jaluit, which was subordinate to the 6th Base Force on Kwajalein, in turn subordinate to the 4th Fleet at Truk. The Yokosuka 6th SNLF, assigned to the Gilberts with headquarters at Tarawa after the Carlson raid, was immediately under the 6th Base Force at Kwajalein. Under this headquarters two subordinate commands were set up at Makin and Apamama. In addition, two new commands were set up under the 6th Base Force—the 43rd Guard Force Dispatched Landing Force on Nauru and the 62nd Guard Force Dispatched Landing Force on Ocean Island. The Gilberts and the nearby islands of Ocean and Nauru were obviously achieving greater status in Japan’s defensive strategy.
Throughout the winter and early spring of 1943 other steps were taken to improve defenses in the Gilberts. Another recognition of the increased importance of this area came on 15 February 1943 when the Yokosuka 6th Special Naval Landing Force was deactivated and the command in the Gilberts was renamed the 3rd Special Base Force. The new command was made responsible not only for the defense of Tarawa, Makin, and Apamama Atolls, but also of Nauru and Ocean Islands. This was a significant command reorganization reflecting clearly the change in Japanese attitude toward the importance of the Gilberts after Carlson’s raid. In the beginning of 1942 Japan had nothing more than a lookout station in the Gilberts subordinated to a guard force command, which was in turn responsible to a base force at Kwajalein. Now, in February 1943, Japanese forces in the Gilberts were constituted as a base force command on an echelon equal to that of the Kwajalein base force command.
Parallel to these developments in command organization was the steady progress being made in fortifying the various islands and improving their military potentialities. Beginning about 1 January 1943, the Japanese steadily shipped 4th Fleet laborers, mostly Koreans, to the islands south of the Marshalls for construction work. Some indication of the cost involved in the fortifications under construction is afforded by the fact that, on 4 March 1943, 7,409,000 yen ($1,736,669.60) was earmarked for air base construction in the Gilberts and land fortifications on Nauru.
An even stronger indication of the increasing importance of the Gilberts to Japanese defensive strategy was the detachment of the Sasebo 7th Special Naval Landing Force from the Southeastern Area Fleet (Rabaul) and its commitment to Tarawa under the 4th Fleet. Arriving in May, the force remained on Tarawa until the American invasion in November.
This move as much as any other single event was evidence of the declining significance attached by the Japanese high command to the Solomon’s-New Guinea area, and by the same token of the increasing importance of the Central Pacific, including the Gilberts. Also in May, the Japanese established a new plan of overall defense called the Z Operation. According to this plan the defensive perimeter was drawn through the Aleutians, Wake, the Marshalls, the Gilberts, Nauru, Ocean, and the Bismarck’s. The principal positions along the perimeter were to be strengthened and local commanders were to be responsible for defense in case of invasion.
Garrison forces at the point of attack were instructed to destroy the enemy at the shore line. If the enemy should succeed in forcing a landing, local forces were to counterattack persistently in an effort to delay the invaders as long as possible and to prevent the establishment of bases.
Meanwhile, construction of fortifications and airfields was proceeding apace. The main concentration of effort was on Tarawa. Concrete and log emplacements for guns of all sizes up through 14 centimeters were constructed, transmitting and receiving stations set up, coconut trees logged and transported from outlying islands, tank barricades and tank pits constructed, underwater obstacles emplaced, and dugouts made for individual riflemen and machine gunners. Similar though not nearly so extensive preparations were being made concurrently on Makin.
The air base on Makin was completed and ready to accommodate reconnaissance and fighter seaplanes by July 1943. At Tarawa construction on an airstrip was begun in October 1942, and a trial landing of a land-based bomber was made on 28 January 1943. By 31 May the major runway on Betio, Tarawa Atoll, was 80 percent completed, positions for planes 100 percent, and a secondary runway 40 percent.
Thus, while high-level staff planners of the Allied forces were gradually coming to the decision to institute a drive across the Central Pacific, the Japanese in that area were preparing against the expected attack as rapidly as conditions permitted.
Necessity had compelled the Japanese to admit the probability of defeat in the Solomon’s-New Guinea area though Rabaul, it is true, had not yet been given up as lost, and valiant efforts were to be made in the autumn of 1943 to save that bastion from disaster. As the year wore on, however, it became more and more apparent that the most immediate threat to Japan’s perimeter defense was in the Central Pacific, and it was here that the Japanese high command hoped to force a showdown with the invading forces from the east.
American Attacks and Japanese Responses
September witnessed the opening of the first large-scale American aerial attacks against the Gilberts and nearby islands. Planes of Admiral Pownall’s fast carrier force, assisted by Army Air Forces B-24’s from Canton and Funafuti, struck Makin, Tarawa, and Nauru on 18-19 September.
According to one Japanese diary, twenty-eight laborers were killed during the strike on Makin, probably from a direct hit on a shelter. The damage done by the raid on Betio was more serious. The runway was hit, although not seriously enough to prevent repair by labor troops. The antenna mast of a receiving station was knocked half down, and a transmitting station completely destroyed. A storehouse and a hospital were completely destroyed, as were the entire air force kitchen and half of the Sasebo 7th Special Naval Landing Force kitchen. The damage to air communications installations was particularly serious. The transmitting station destroyed by the air raid was evidently the chief means of communication with other islands and on Betio itself, judging by the measures taken to restore it—two transmitters were borrowed from the Sasebo 7th Special Naval Landing Force (one set from the receiving room and one from the medium attack plane command post) and another from the 3rd Special Base Force.
Following the raid, one of the island defenders wrote in his diary: “The island is a sea of flames. . . . Seven of our medium attack bombers were destroyed and a great number of our guns were damaged. Moreover, shell dumps, ammunition dumps, various storehouses and barracks on Bairiki [the island just east of Betio] were destroyed. A great number of men were killed and wounded.”
Whether or not this individual report was exaggerated, the response of the Japanese at Tarawa was immediate. On 24 September, Rear Admiral Keiji Shibasaki, IJN, commanding officer of the 3rd Special Base Force, ordered the commanding officers of the 111th Construction Unit and the 4th Fleet Construction Department Detachment to build immediately a bombproof shelter for communications equipment. Later, it was reported: “Work was started immediately and is scheduled to be completed during October. After the work is completed, one transmitter and three receivers will be installed in the station. No matter what happens, we hope to be able to maintain radio communications.” At the same time work was begun on a transmitting station, which according to plans was to be of concrete and to contain three short-wave transmitters and one longwave transmitter with attachments. Completion date was scheduled for December.
Another important result of the September raids was the evacuation of aircraft from Tarawa. Before the raids there had been three air installations in the 3rd Special Base Force area, airfields at Nauru and Tarawa, and a seaplane base at Makin.
One of the most important duties of these installations was to maintain patrols in the southeast corner of the Japanese-held Central Pacific. Patrols from Nauru covered the area south of that island; patrols from Makin covered the area to the east; and patrols from Tarawa extended to the southeast between the other two. The Japanese had originally intended to build up the Tarawa airfield and plane complement to considerable strength, and by early September there were 330 air personnel on the island and 18 planes. However, the Allied carrier strike of 18-19 September seriously disrupted operations and installations and destroyed nine of the planes. After this it was decided to evacuate the air units, and Tarawa was never again used as a Japanese air base. After the removal of the planes from Tarawa, Makin assumed full responsibility for patrolling the Gilberts. By November there were only four amphibious reconnaissance planes at Makin charged with the dual mission of reconnaissance and antisubmarine patrol. For all practical purposes, Japanese local air defenses were eliminated by the strikes of 18-19 September.
Meanwhile, the Japanese Navy was preparing its own plans for a defense of the Gilberts-Marshalls area and for a decisive engagement with the U.S. Pacific Fleet. Plans for the defense of the Gilberts by the Japanese Fleet were drawn up about 8 September 1943 and included the following moves:
(1) Large and, if possible, small submarines in the Rabaul area were to move up and operate in the vicinity of the Gilberts.
(2) The 2nd Fleet was to advance and operate in an area west and north of Nauru so as to decoy the U.S. Pacific Fleet. Then, after thirty-six land-based attack planes from Rabaul had carried out attacks against the invading fleet, the 2nd Fleet was to move up to the Mille area and continue operations.
(3) If necessary, a destroyer squadron was to come up from the Rabaul area and participate in the operations.
(4) Planes of the 3rd Fleet that were undergoing training were to join in these operations if necessary, regardless of the amount of training they had completed.
In September 1943 the main striking force of the Japanese Navy was based at Truk and was under the command of Admiral Mineichi Koga, Commander in Chief, Combined Fleet. It consisted chiefly of the super battleships Yamato and Musashi, and two battleships and a destroyer squadron from the 1st Fleet. Also included in Koga’s force were the 2nd and 3rd Fleets, which had the combined strength of 3 carriers, 2 battleships, 11 heavy cruisers, 3 light cruisers, and a large number of destroyers.
It was this force that Koga tried to hold together for a decisive blow against the U.S. Fleet. His was “ . . . not a plan of any positive action to draw the American Fleet into a decisive action, but rather to wait until the American Fleet came up; and he felt sure that they were bound to come up if he only waited.”
On two occasions before the American landings on Makin and Tarawa, Koga sortied from Truk with part of this formidable task force in the hope of meeting American warships. Each time he had to return to his home base without having given battle. The first expedition occurred in September when the admiral learned that Pownall’s fast carrier force was approaching the Marshalls-Gilberts area. Immediately he dispatched a large force, composed of elements of the 2nd and 3rd Fleets, which proceeded to Eniwetok, the location from which he considered it best to base an attack. The force consisted of 3 carriers, 2 battleships, 7 heavy cruisers, and 3 light cruisers. It left Truk on 18 September and arrived at Eniwetok on the 20th. Not finding the expected American task force (then operating well to the south and east) the Japanese fleet returned to Truk.
The second large fleet sortie from Truk occurred in October when Koga’s radio intelligence indicated the strong possibility of an Allied raid against Wake or the Marshalls. Koga, hoping that this was the opportunity for the decisive engagement he had missed the previous month, once again dispatched a large fleet from Truk to Eniwetok on 17 October. The October force was even more powerful than the September one. Included were the same 3 carriers, plus 6 battleships, 8 heavy cruisers, and 3 light cruisers. These ships remained in Eniwetok for a few days then sailed north some 300 miles toward Wake and returned once again to Truk. No elements of the American fleet were encountered. Pownall’s carriers, which had conducted a highly successful strike against Wake on 5-6 October, were by that time safely back in the Pearl Harbor area.
While Admiral Koga was playing cat and mouse with the elusive American task forces in the Marshalls, American pressure was threatening the Japanese Southeast Area. At the end of September Imperial General Headquarters adopted an operational policy for the Rabaul area “consisting merely of a whittling-down campaign against the enemy which relied upon the momentary use of crucial battle forces when conditions were favorable.” This policy was embodied in the RO Operation, which was to utilize the planes of Koga’s Carrier Division 1 from land bases in the Rabaul area, and was to have been activated around the middle of October. Since the carriers of Division 1 were the only vessels of this type in the entire Japanese Navy with anywhere near full plane complements at the time, the RO Operation would partially incapacitate the Japanese Fleet. It was undoubtedly this consideration that led Koga to postpone the RO Operation in order to make one last attempt at a decisive naval engagement while he still had his fleet intact. After failing in this attempt and after his arrival at Truk on 26 October, he ordered the RO Operation activated and took steps to dispatch the planes of Carrier Division 1 to the Rabaul area. This decision had a profound, and from the American point of view, wholly beneficial effect on the forthcoming invasion of the Gilberts and Marshalls.
Leaving their carriers behind at Truk, a total of 173 planes of Carrier Division 1 flew down to Rabaul on 1 November and remained in the area until the 13th. While there, they engaged in three air battles and lost 121 planes or roughly two thirds of the entire force. At the same time, on receiving word of the Allied landing at Bougainville (1 November), Admiral Koga dispatched the 2nd Fleet along with elements of the 3rd Fleet to Rabaul. The force arrived at Rabaul on 5 November and was immediately subjected to a fierce attack by planes from Rear Admiral Frederick C. Sherman’s fast carrier force (Task Force 38) and again on the 11th not only by Sherman’s force but also by Admiral Montgomery’s Task Group 50.3. Altogether, four of Koga’s heavy cruisers (Takao, Maya, Atago, and Mogami) were so damaged during these strikes as to be nonoperational during the Gilberts invasion.
[NOTE NB-44G: USSBS, Interrogations of Japanese Officials, Vol. II, p. 516. Perhaps even more important than the plane losses was the attrition of carrier pilots. Of 192 flight crews from Carrier Division 1 dispatched to the Rabaul area in November 1943, 86 were lost. Japanese Studies in World War II, No. 50, Vol. III, p. 26.]
Another two (Myoko and Haguro) had been put out of operation by gunfire and by collision during the initial landings on Bougainville at Empress Augusta Bay. Still another (Tone) was in dry dock undergoing periodic check-up. Thus, of the eleven heavy cruisers that Koga had had under his command in September of 1943, only four remained operational in mid-November. All but one of the remainder had been temporarily put out of operation at Rabaul or Bougainville.
The loss of these cruisers, coupled with the tremendous attrition of carrier planes at Rabaul, meant that the Japanese battleships based at Truk were virtually immobilized, since they would not dare enter combat without proper protection. The sorry plight in which the Japanese Navy now found itself, facing as it did an impending American invasion of the Central Pacific, can best be summarized in the words of Vice Admiral Shigeru Fukudome, IJN: But in November, as Bougainville landing operations commenced, he [Koga] was forced to send his air strength to Rabaul. As it turned out, practically all of them were lost at Rabaul and Bougainville. Consequently, the Fleet air strength was almost completely lost, and although the Gilberts fight appeared to be the last chance for a decisive fight, the fact that the fleet’s air strength had been so badly depleted enabled us to send only very small air support to Tarawa and Makin. The almost complete loss of carrier planes was a mortal blow to the fleet since it would require six months for replacement. … In the interim, any fighting with carrier force was rendered impossible.
No better testimony could be adduced to the mutual interdependence of the various Allied forces operating in different areas of the Pacific. Without the tremendous losses inflicted on the Japanese by forces under General MacArthur and Admiral Halsey, the Central Pacific forces under Admiral Nimitz would certainly have faced far greater odds in their invasion of the Gilberts.
Japanese Defenses on the Eve of the Attack
By the morning of 20 November when the ships of Admiral Turner’s Northern Attack Force hove into view of Makin Atoll, the Japanese had on the main island of Butaritari an estimated 798 men under command of Lt. (j.g.) Seizo Ishikawa, commander of the 3rd Special Base Force Makin Detachment. This figure by no means represents the enemy’s combat strength since the majority were labor troops (mostly Korean) whose combat effectiveness was only slightly more than nil. The organization of Japanese forces on D Day was roughly as follows: 3rd Special Base Force Makin Detachment.(284); Air personnel (100); 111th Construction Unit.(138); 4th Fleet Construction Department Detachment (276). The air personnel were ground crews left marooned on the island after the planes had escaped. How well they were armed or how effective they were as combat troops it is impossible to know. Of the labor troops, about 220 were Korean, the remainder Japanese who were not in the service either because of age or physical infirmities. None of the labor troops was assigned a battle station and none had any training, although it appears that the Japanese workers and perhaps a few Koreans were issued rifles on D Day. Thus, the maximum total of trained combat troops on Makin came to no more than 384, and the actual number was probably no more than 300.
As to defense installations, the Japanese had been able or willing to fortify Butaritari with only a bare minimum. A perimeter defense had been established around the seaplane base on the lagoon shore. Defenses on the lagoon shore were comparatively light, consisting mainly of three dual-purpose 8-cm. guns at the base of King’s Wharf and a few machine guns. Running from the lagoon to the ocean were two tank barrier systems, each partially guarded by strands of trip wire and covered by antitank guns, machine guns, and rifle pits. The West Tank Barrier was made up of a wide ditch and a coconut log barrier. The ditch extended from the lagoon approximately two thirds of the way across the island, was 12 to 13 feet wide, and about 5 feet deep. The log barrier, starting at the south end of the ditch and extending to the ocean shore, was about 4.5 feet high and braced from the east by diagonal logs. Altogether a total of one antitank gun, one concrete pillbox, 6 machine gun positions, and 50 rifle pits covered this barrier.
The East Tank Barrier, more heavily fortified than that to the west, consisted of a trench 14.5 feet wide by 6 feet deep stretching from the lagoon about two thirds of the way across the island and bent in the middle toward the westward. From the southern terminus of this trench to the ocean shore a log antitank barricade had been erected and a similar barricade lay to the east of the northern section of the trench. Double-apron wire and trip wire had been laid in continuous lines across the entire island in the same area. West of the trap itself was an intricate system of gun emplacements and rifle pits. Three pillboxes of either log or cement barred the approach to the trap. Lying between these emplacements and connecting them was a series of forty-three rifle pits, interspersed with machine guns. Immediately to the west of this line in the center of the island was another group of twenty-three rifle pits. On the south shore between the terminus of the road running from the end of Stone Pier and the southern end of the tank barrier were located nineteen more rifle pits, two machine guns, and a 70-mm. howitzer, all placed to protect the ocean shore.
Along the ocean shore a series of strong points had been established, incorporating 3 8-cm. coast defense guns, 3 antitank positions, 10 machine gun emplacements, and 85 rifle pits. Obviously, the Japanese expected that any invasion of the island would be made on the ocean shore, following the example of Carlson’s raid. On either side of the heavily defended area was an outpost consisting of a squad of men, a lookout tower approximately 70 feet high, and telephone communication to command posts within the fortified area. The defended area was divided into three parts. Aviation personnel were quartered in the eastern portion, the majority of the garrison force lived in the center, and the Korean laborers were billeted in the western part.
The island of Betio in Tarawa Atoll was much more heavily manned and fortified. There the garrison, commanded by Admiral Shibasaki, consisted of an estimated 4,836 men organized as follows: Total = 4,836: 3rd Special Base Force (1,122); 7th SNLF (1,497); 111th Construction (1,247); 4th Fleet Construction Department Detachment (970). Of this number, the members of the 3rd Special Base Force and the Sasebo 7th Special Naval Landing Force were trained combat troops. The extent of combat effectiveness of the labor troops on the island is more difficult to determine. The combat importance of these construction units usually varied with the number of Japanese personnel since the Koreans were almost never given weapons. The 4th Fleet Construction Department was about 85 percent Korean and the 111th Construction Unit about 30 percent Korean. Thus, if all of the Japanese laborers at Tarawa were trained and equipped for combat, the total effective strength on that atoll would have been over 3,600. However, it appears that the military organization of the labor troops may have existed mostly on paper, and the training program set up for them by the Japanese, even if carried out, would at best have provided a reserve force of limited value. Thus, a safe guess as to the number of combat effectives on Tarawa would probably be about 3,000.
Betio itself had been built into an island fortress of the most formidable aspect. The island had been organized for an all-round decisive defense at the beach. The basic beach defense weapon along the entire north coast and on both sides of the eastern tip was the 13-mm. machine gun. Along the western and southwestern coasts the 7.7-mm. machine gun was used for the same purpose. The guns were located in open emplacements to allow the additional mission of antiaircraft fires. Those on the northern coast were so positioned as to permit flanking fire to the front of artificial barriers (tetrahedrons) that had been emplaced along the reef, or frontal fire on the direct approaches to the beach.
Inshore, organization for defense was more haphazard. Bombproof ammunition and personnel shelters were put to use as defensive positions in depth, although they had not originally been constructed for that purpose. In some cases, the fire from the doorways of these shelters was mutually supporting, but this was only by accident.
For the most part they were blind to attack from several directions, and since they had not been designed as blockhouses, had only a few firing ports. The basic weapons were complemented by a network of obstacles including antitank ditches, beach barricades, log fences and concrete tetrahedrons on the fringing reef, double-apron-high-wire fences in the water near the beach, and double-apron low-wire fences on the beach itself. The larger obstacles on the reef were designed to canalize the approach of boats into areas that could be swept effectively by anti-boat fires from 127-mm., 80-mm., 7-cm., 37-mm., and 13-mm. guns. The lighter double-apron fences were laid along diagonal lines from the beaches, and machine guns were emplaced in every case so that flanking fires could be laid parallel to the wire and just forward of it. Altogether, on Betio there was a total of four 8-inch guns, four 14-cm., four 12.7 cm., six 8-cm., ten 75-mm. mountain guns, six 70-mm. howitzers, eight 7-cm. dual-purpose single mounts, nine 37-mm. field guns, twenty-seven 13-mm. single mounts, four 13-mm. double mounts, and seven tanks mounting 37-mm. guns.
Fire control equipment was installed for the coast defense, and antiaircraft batteries, including range finders, directors, and searchlights, had been set up. For the most part weapons were mounted in carefully and strongly constructed emplacements of coconut logs, reinforced concrete, and revetted sand. Ammunition and personnel were protected from shelling and bombing by log and concrete bombproof shelters covered with sand to increase safety and improve camouflage. These shelters were ordinarily placed opposite the interval between, and inshore of, pairs of guns. Heavy gun ammunition was handled from bombproof shelters to ready boxes in concrete emplacements by narrow-gauge railway and overhead chain hoist gear.
This bare recital of enemy defense installations on Betio does only scant justice to the really horrible obstacles that the attacking forces would have to overcome. Tarawa was the most heavily defended atoll that would ever be invaded by Allied forces in the Pacific. With the possible exception of Iwo Jima, its beaches were better protected against a landing force than any encountered in any theater of war throughout World War II. Makin, by comparison, was lightly held. But any beach guns that are manned and ready to fire are formidable enough to the men of the first waves of an amphibious landing force.
Boated in slow-moving craft, as they make their way from ship to shore they offer ideal targets to the waiting defenders—unless the latter have been destroyed, or at least dispersed, by the attackers’ naval and aerial bombardment. It was the hope of the landing forces at both Makin and Tarawa that this would be accomplished before the first troops touched shore.
SOURCE: Seizure of the Gilberts and Marshalls: BY; Philip A. Crowl, & Edmund G. Love (United States Army Center of Military History)