The end of the Aleutian Islands Campaign and progress in the Solomon Islands, combined with increasing supplies of men and materials, gave the United States Navy the resources to make an invasion of the central Pacific in late 1943. Admiral Chester Nimitz had argued for this invasion earlier in 1943, but the resources were not available to carry it out at the same time as Operation Cartwheel, the envelopment of Rabaul in the Bismarck Islands. The plan was to approach the Japanese home islands by "island hopping": establishing naval and air bases in one group of islands to support the attack on the next. The Gilbert Islands were the first step in this chain.
On 10 December 1941, three days after the attack on Pearl Harbor, 300 Japanese troops, plus laborers of the so-called Gilberts Invasion Special Landing Force had arrived off Makin Atoll and occupied without resistance. Lying east of the Marshall islands, Makin would make an excellent seaplane base, extending Japanese air patrols closer to Howland Island, Baker Island, Tuvalu and Phoenix and Ellice Islands, all held by the Allies and protecting the eastern flank of the Japanese perimeter from an Allied attack.
On 17 August 1942, 211 Marines of the 2nd Marine Raider Battalion under command of Colonel Evans Carlson and Captain James Roosevelt were landed on Makin from two submarines, USS Nautilus and USS Argonaut. The Japanese garrison only posed 83 to 160 men under the command of a warrant officer. The Raiders killed at least 83 Japanese soldiers, annihilating the garrison, and destroyed installations for the loss of 21 killed (mostly by air attack) and 9 captured. The Japanese moved their prisoners to Kwajalein Atoll, where they were later beheaded. One objective of the raid was to confuse the Japanese about U.S. intentions in the Pacific, but it had the effect of alerting the Japanese to the strategic importance of the Gilbert Islands and led to their further reinforcement and fortification.
After Carlson's raid, the Japanese reinforced the Gilberts, which had been left lightly guarded. Makin was garrisoned with a single company of the 5th Special Base Force (700 - 800 men) on August 1942, and work on both the seaplane base and coastal defenses of the atoll was resumed in earnest. By July 1943 the seaplane base on Makin was completed and ready to accommodate Kawanishi H8K "Emily" flying boat bombers, Nakajima A6M2-N "Rufe" hydrofighters and Aichi E13A "Jake" Recon-hydroplanes. Its defenses were also completed, although they were not as extensive as on Tarawa Atoll—the main Japanese Navy air base in the Gilberts. The Chitose and 653rd Air Corps were detached and deployed here. While the Japanese were building up their defenses in the Gilberts, American forces were making plans to retake the islands.
In June 1943 the Joint Chiefs of Staff directed Admiral Chester W. Nimitz, Commander in Chief of the Pacific Fleet (CINCPAC), to submit a plan to occupy the Marshall Islands. Initially both Nimitz and Admiral Ernest J. King, the Chief of Naval Operations, wanted to attack right into heart of the Japanese outer defense perimeter, but any plan for assaulting the Marshalls directly from Pearl Harbor would have required more troops and transports than the Pacific Fleet had at the time. Considering these drawbacks and the limited combat experience of the U.S. forces, King and Nimitz decided to take the Marshalls in a step-by-step operation via the Ellice and Gilbert Islands. The Gilberts lay within 200 miles (300 km) of the Southern Marshalls and were well within range of United States Army Air Forces B-24 aircraft based in the Ellice Islands, which could provide bombing support and long-range reconnaissance for operations in the Gilberts. With those advantages in mind, on 20 July 1943 the joint Chiefs of Staff decided to capture the Tarawa and Abemama atolls in the Gilberts, plus nearby Nauru Island. The operation was codenamed "Operation Galvanic."
On 4 September the U.S. 5th Fleet's amphibious troops were designated the V Amphibious Corps and placed under Marine Corps Major General Holland M. Smith. The V Amphibious Corps had the only two divisions, the 2nd Marine Division based in New Zealand and the U.S. Army's 27th Infantry Division based in Hawaii. The 27th Infantry Division had been a New York National Guard unit before being called into federal service in October 1940. It was transferred to Hawaii and remained there for 1½ years before being chosen by Lt. Gen. Robert C. Richardson, Jr., the U.S. Army Commanding General in Central Pacific, to take part in the Gilbert Islands invasion. Captain James Jones (father of former-Commandant of the Marine Corps James L. Jones), the Commanding Officer of Amphibious Reconnaissance Company, VAC served abroad the submarine USS Nautilus in periscope reconnaissance of the Gilberts, establishing accurate accounts of the beachheads for the upcoming invasion.
The 27th Division was tasked to supply the landing force with one regimental combat team (the 165th Infantry Regiment) reinforced by a battalion landing team (the 3rd Battalion, 105th Infantry Regiment), supported by the 105th Field Artillery Battalion and the 193rd Tank Battalion, under the command of Major General Ralph C. Smith, a veteran of World War I, who had assumed command in November 1942. He was one of the most highly respected officers in the U. S. Army at the time. In April 1943 the 27th Infantry Division had begun preparing for amphibious operations.
Planning for the 27th Infantry Division's role in "Galvanic" (the Army portion was codenamed "Kourbash") began in early August 1943, with Nauru Island in the western Gilberts as the original objective. Unlike the other objectives, Nauru was an actual island, much larger in size and more heavily garrisoned.
However, in September 1943 the 27th's objective changed. The difficulty of providing adequate naval and air support of simultaneous operations at Tarawa and the much more distant Nauru, plus lack of sufficient transport to carry the entire division required to take the larger, more heavily defended Nauru, caused Admiral Nimitz to shift the 27th's objective from Nauru to Makin Atoll, in the northeast Gilberts. The 27th Infantry Division staff learned the change of target on 28 September, scrapped the original Nauru plan, and began planning to capture Makin.
Heavy aircraft losses and the disabling of four heavy cruisers in the Solomon Islands meant that the original Japanese plan of a strike at the American invasion fleet by forces based at Truk in the nearby Caroline Islands (South Pacific Mandate) was scrapped. The garrisons at Tarawa and Makin were left to their fate.
The invasion fleet, Task Force 52 (TF 52) commanded by Rear Admiral Richmond K. Turner left Pearl Harbor on 10 November 1943. The landing force, Task Group 52.6, consisted of units of the 27th Infantry Division commanded by Major General Ralph C. Smith, transported by attack transports Neville, Leonard Wood, Calvert, and Pierce; attack cargo ship Alcyone; landing ship dock Belle Grove; and LSTs -31, -78, and -179 of Task Group 52.1.
On the eve of invasion, the Japanese garrison on Makin Atoll's main island, Butaritari, numbered 806 men: 284 naval ground troops of the 6th Special Naval Landing Force, 108 aviation personnel of the 802nd and 952nd Aviation Units, 138 troops of the 111th Pioneers, and 276 men of the Fourth Fleet Construction Department and Makin Tank Detachment of 3rd Special Base Force (3 Type 95 Ha-Go Light Tanks), all commanded by Lt.j.g. Seizo Ishikawa. The number of trained combat troops on Makin was no more than 300 soldiers.
Butaritari's land defenses were centered around the lagoon shore, near the seaplane base in the central part of island. There were two tank barrier systems: The west tank barrier extended from the lagoon two-thirds of the way across Butaritari, was 12 to 13 feet (4.0 m) wide and 15 feet (4.6 m) deep, and was protected by one anti-tank gun in a concrete pillbox, six machine gun positions, and 50 rifle pits. The east tank barrier, 14 feet (4.3 m) wide and 6 feet (1.8 m) in depth, stretched from the lagoon across two-thirds of island and bent westward with log antitank barricades at each end. it was protected by a double apron of barbed wire and an intricate system of gun emplacements and rifle pits.
A series of strongpoints was established along Butaritari's ocean side, with 8-inch (200 mm) coastal defense guns, three 37 mm anti-tank gun positions, 10 machine gun emplacements and 85 rifle pits. The Japanese expected the invasion to come on the ocean side of Butaritari, following the example of Carlson's raid in 1942, and established their defenses two miles (3 km) from where the raid had taken place. Without aircraft, ships, or hope of reinforcement or relief, the outnumbered and outgunned defenders could only hope to delay the coming American attack for as long as possible.
Air operations against Makin began on 13 November, with USAAF B-24 bombers of the Seventh Air Force from Ellice. Grumman FM-1 "Wildcat" fighters escorted Douglas SBD "Dauntless" dive bombers and Grumman TBF "Avengers" from escort carriers USS Liscome Bay, USS Coral Sea and USS Corregidor; followed by 8-inch (200 mm) support guns from fire support ship USS Minneapolis and other war vessels. Troops began to go ashore at two beaches at 08:30 on 20 November.
The initial landings on RED Beach went according to plan with the assault troops moving rapidly inland after an uneventful trip on the ocean side of the island. Their progress off the beach was slowed only by an occasional sniper and the need to negotiate their way around the debris and water-filled craters left by the air and naval bombardment. The craters in particular stymied tank support of the Red beach forces by the light tanks of the 193rd Tank Battalion when the lead M3 light tank became partially submerged in a shellhole and blocked passage of all the vehicles behind it.
As the landing craft approached YELLOW Beach from the lagoon, they began to receive small-arms and machine-gun fire from the island's defenders. The assault troops were also surprised to learn that even though they were approaching the beach at high tide as planned, a miscalculation of the depth of the lagoon caused their small boats to go aground, forcing them to cover the final 250 yards (230 m) to the beach in waist-deep water. Although equipment and weapons were lost or water-soaked, only three men were killed approaching the beach, mainly because the defenders had elected to make their final stand not at the waterline, but farther inland along the tank barriers.
The invasion plan was conceived in the hope of luring the enemy into committing most of its forces to oppose the first landings on RED Beach and thereby allow the troops landing on YELLOW Beach to attack from the rear. The enemy, however, did not respond to the attack on RED Beach and withdrew from YELLOW Beach with only harassing fires, leaving the troops of the 27th Division no choice but to knock out the fortified strongpoints one by one. Reduction operations were hampered by the frequent inability to use heavy support weapons, including tanks, because of the danger of cross-fire. The regimental commander of the 165th Infantry, Colonel J.G. Convoy, was killed in action by Japanese machinegun fire on the afternoon of the first day.
Two days of determined fighting reduced enemy resistance. After clearing the entire atoll, the 27th Division commander, Maj. Gen. Ralph C. Smith, reported on the morning of 23 November, "Makin taken, recommend command pass to commander garrison force." In the end the most difficult problem in capturing Makin was coordinating the actions of the two separate landing forces, a problem made more difficult because the defenders did not respond as had been anticipated. The lack of suitability of the narrow beaches to support supply landing operations, which was not discovered by pre-invasion reconnaissance, also proved a severe handicap.
The complete occupation of Makin took four days and actually cost more in naval casualties than in ground troops. Despite its great superiority in men and weapons, the 27th Division had considerable difficulty subduing the island's small defensive force. One Japanese Ha-Go tank was destroyed in combat, and two tanks placed in revetments were abandoned without being used in combat.
As compared to an estimated 395 Japanese killed in action during the operation, American ground casualties numbered 218 (66 killed and 152 wounded). Losses to U.S. Navy personnel were significantly higher: 644 deaths on the Liscome Bay, 43 killed in a turret fire aboard the battleship Mississippi, and 10 killed in action among naval shore party and aviators, totalling 697 naval deaths in the battle. Thus, the overall total of 763 American dead nearly equalled the number of men in the entire Japanese garrison.