Tarawa Atoll is a series of small islands in the Gilberts. The major Japanese outposts were on Betio, a bird-shaped island in the southern part of the chain; and Makin, which was raided early in 1942 by US Marines. Nine leathernecks who were mistakenly left behind were executed, but the raid was considered a success, especially by a victory-starved American public.
After the Battle of Midway and especially after the fall of Guadalcanal, the Japanese Imperial Navy began to fortify the Gilberts. Rear Admiral Keiji Shibasaki, commander of Betio, received four of the heavy guns from Singapore that the British hoped would turn back an invasion. Shibasaki announced that a million men could not take Tarawa in a hundred years." It would take 35,000 men four days to conquer Tarawa; at the end of the battle, neither side would look at the war the same way.
Tarawa was far more heavily fortified than any island the Allies had encountered before; to attack it the growing strength of the United States Navy would mobilize a fleet of dozens of ships. On November 22, 1943, after a three-hour bombardment, the 2nd Marine Division landed on Betio. Shibasaki had 2500 Imperial Naval Marines, with 2,300 Korean and Japanese laborers. They had transformed Betio into a fortress of unparalleled intricacy, with coconut log bunkers cemented with crushed coral and intersecting zones of fire. The fire thrown against the US Marines was intense, and within the first hour the first wave had suffered almost total casualties. The amtracs, mobile personnel carriers that could operate on land and water, were in high demand by Americans, but were being destroyed one by one.
In contrast, the landings on Makin had much lower casualties for the Americans. The smaller garrison died almost to a man. Additional landings on smaller islands in the Gilberts were accomplished by submarine.
The coral reef prevented the Higgins boats from landing directly on the shore; the Americans had to wade in. They drowned in hidden holes in the reef, and were caught by machine gun fire from a bombed out ship on the shore. Once on land, they had only the sand between the ocean and the seawall, only a few yards wide. By the end of the first night, it was not definite that the Americans were here to stay.
Like the Japanese Navy in the Solomons, the Americans were losing their junior officers and noncommissioned officers rapidly. Advance was only due to a sergeant or a lieutenant leading their squad or platoon over the wall and moving inland. The Japanese would not give up. They would fire until they had one bullet and kill themselves with their big toe in the trigger of their rifle.
By the third day, the American Marines were moving across the island in a battle that had turned into a series of small unit actions. Dead and wounded mounted on both sides, and even the division reserve could not turn the tide. At dusk the Americans had taken enough ground to ensure that Tarawa would be taken; the only question was the amount of blood. Shibasaki and his entire command staff died sometime on the third day, committing suicide rather than face capture. Few Japanese surrendered; only 17 prisoners of war were alive at the end of the battle.
That night, the remaining Japanese and the Korean laborers came out of their last positions and charged. Some 300 men attacked in a desperate gambit to inflict as many casualties as possible. The attack was not as organized as the Banzai on Attu; it may have actually shortened the battle. If those men had died in their pillboxes, certainly many more Americans would have died.
Nimitz's office was flooded with angry letters over the number of American dead on Tarawa. Most of the Japanese family members did not receive final word on their loved ones until the war was over. The Koreans were not even identified.
After Tarawa, the Americans built practice bunkers and developed new tactics on how to destroy them. The length of pre-invasion bombardment was increased, and more and better amtracs were ordered from the factories. The Marine survivors of Betio were sent to train the replacements in how to fight and win in island warfare.