Between November 20 and 23, 1943, American forces captured Betio Island in the Tarawa Atoll using a contingent of 35,000 troops. This victory was especially notable given that Japanese estimates had suggested it would require a million soldiers and take a hundred years to accomplish.
The Battle of Tarawa represented the first American offensive in the Central Pacific and was the first instance of Japanese forces resisting a US amphibious assault. Throughout the four-day conflict, essential lessons were learned that proved crucial for the success of subsequent landings.
Betio island and the American strategy
Approximately 2,400 miles southwest of Pearl Harbor, Betio Island played a crucial role in America’s strategic plans in the Pacific Theater during the Second World War. The United States, employing its “island-hopping” strategy aimed to establish bases in the Marianas to support operations throughout the region, including those in the Philippines and Japan. Nevertheless, prevailing naval doctrine required land-based aircraft to protect invasion forces and weaken enemy defenses.
The Marshall Islands were identified as the nearest suitable locations for constructing an airbase to launch such attacks. Yet, one significant obstacle stood in the way: a Japanese garrison and airbase on Betio, in the Tarawa Atoll, which disrupted direct communication with Hawaii. To secure the Mariana Islands, the Americans first needed to capture this small island.
The Japanese forces fortified the coast of Tarawa
It wouldn’t be a simple invasion. In February 1943, the Japanese 3rd Special Base Defense Force (previously the 6th Yokosuka Special Naval Landing Force) reinforced Betio. The garrison stationed on the island comprised Imperial Japanese Navy (IJN) troops; the 3rd Special Base Defence Force was 1,112 men strong and was reinforced by the 7th Sasebo Special Naval Landing Force, consisting of 1,497 men and commanded by Cmdr. Takeo Sugai.
Under the command of Rear Adm. Tomonari Saichirō, the Defense Force began constructing sophisticated defensive structures on Betio. The goal of the scheme was to halt any invasions by stopping attackers in the water or pinning them on the beaches.
It took 1,247 men of the 111th Pioneers and 970 men of the Fourth Fleet’s construction battalion almost an entire year to fortify the island, during which time they constructed 500 pillboxes and 40 artillery pieces along the beaches. On top of this, 14 coastal defense guns were prepped, including massive BL 8-inch howitzers that had been purchased from the British in the early 1900s.
The battalion cut an airfield into the center of Betio and dug trenches that connected all parts of the island, allowing troops to move to where they were needed. However, the Japanese didn’t anticipate much fighting in the interior.
Rear Adm. Keiji Shibazaki, an experienced combat officer, took over on July 20, 1943, in anticipation of the coming fight, and preparations continued until the day of the invasion that November.
The Americans assembled a large landing force
Following the completion of the Guadalcanal Campaign in February 1943, the 2nd Marine Division withdrew to New Zealand to replace their losses. On July 20, the Joint Chiefs of Staff, led by Adm. Chester Nimitz, began preparing for an offensive in the Gilbert Islands. Adm. Raymond A. Spruance flew to New Zealand to meet with Gen. Julian C. Smith, the new commander of the division, to begin planning the invasion.
The American plan was to land Marines on the north beaches, which were divided into three sections: Red Beach 1 on the far west; Red Beach 2 in the center, west of the pier; and Red Beach 3 to the east. Green Beach was a contingency landing on the western shoreline, while the two Black Beaches weren’t used.
This was opposite to what the Japanese had anticipated. They’d thought the coastal guns placed to the north to protect the lagoon would make it too hard for forces to attack from that area. For the Marines, the goal was to secure the airstrip, which divided the island into north and south.
At the time, the American invasion force assembled on the Gilbert Islands was the largest ever gathered for a single operation in the Pacific. They consisted of 17 aircraft carriers, 12 battleships, eight heavy cruisers, four light cruisers, 66 destroyers and 36 transport ships. Around 35,000 men from the 2nd Marine and the US Army’s 27th Infantry Divisions were aboard the transports.
The Battle of Tarawa begins
The Battle of Tarawa began in the predawn hours of November 20, 1943, as the island’s coastal guns and the main batteries aboard the American battleships USS Colorado (BB-45) and Maryland (BB-46) engaged in counter-battery fire to the north. These were able to knock out three of the four guns rather quickly, and the resulting damage left the lagoon open.
The following naval bombardment of the beach at 6:10 AM lasted for the next three hours. Once complete, the US Marines began attacking from the lagoon. However, as the tide hadn’t risen as expected over the reefs below, their shallow draft Higgins boats were unable to clear the lagoon. The Marine Corps had been warned by a New Zealand Army Liaison Officer that there was a 50 percent chance that the tide wouldn’t rise, yet the attack hadn’t been delayed.
The US forces’ inability to land their Higgins boats meant the vessels had to be abandoned and those aboard were forced to wade through the deep water to shore. Not only did this leave them vulnerable to enemy fire and cause the landing to take longer than anticipated, but their equipment also became waterlogged.
This had disastrous consequences, as it allowed the Japanese to recover and call up additional troops from the southern beaches, and the Marines who’d managed to make it ashore wound up pinned behind a sea wall. By the end of the first day, the Americans had struggled to secure a small beachhead and the extreme western tip of the island, with the Marines, in particular, seeing 1,500 casualties – 30 percent of those sent ashore that day.
Slowly defeating the Japanese on Betio island
On the second day, the US forces continued to work inland toward the airstrip, with the goal of securing the beaches. The Marines had greater success landing on the western Green Beach, where they quickly secured the beachhead, despite heavy fire from the troops stationed in the pillboxes. Similar resistance was met and neutralized on the Red Beaches, with the Americans controlling the entire western side of Betio by the end of November 21, 1943.
The third day saw the Marines advance east, and they moved heavy equipment and tanks ashore on the Green Beach. As well, the forces that had originally landed on the northern beach made progress toward Red Beach 2, but took casualties in the process.
By the afternoon, the 1st Battalion, 6th Marine Regiment, who’d landed on Green Beach, began the offensive. They pressed the Japanese along the southern coast and formed a contentious line with the men who had landed on Red Beach 3, on the eastern end of the airfield.
Later that night, the Japanese forces formed up for a counterattack. The assault began at 7:30 PM, but the assembling forces were broken up by concentrated artillery fire, thereby thwarting the enemy’s efforts.
American victory over the Japanese
In the pre-dawn hours of November 23rd, 1943, desperate Japanese forces launched a final, ferocious banzai charge.Met head-on by the US Marines, the fight was brutal. While the Marines managed to take out 325 attackers, their own ranks also sustained significant losses with 45 killed and 128 wounded. Later that morning, the Japanese attempted another banzai attack, but it was met with a resolute defense and was ultimately repelled.
By 7:00 AM, American airpower joined the fray, with Navy fighters and bombers focusing on the eastern edge of Betio with a punishing bombardment. This relentless aerial assault, coupled with continued shelling throughout the day, finally overwhelmed the remaining Japanese resistance. With this, the brutal Battle of Tarawa drew to a close.
The American victory came at a heavy cost. Over 3,100 casualties were sustained, while the Japanese force was nearly wiped out, suffering more than 4,600 losses. Despite achieving their objective, the staggering number of American dead for a seemingly insignificant island raised serious questions about the strategic importance of Tarawa in the grand scheme of the Pacific War.
Legacy of the Battle of Tarawa
Much was learned from the Battle of Tarawa, given it was the first time the Americans had experienced any real resistance during an amphibious landing. This not only highlighted the challenges of such opposition, but it also changed the way in which landings like this were conducted.
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Two changes of note were the addition of armor-piercing shells, given the lack of effectiveness of explosive ones in damaging the Japanese troops’ strongholds, and the creation of Underwater Demolition Teams (UDTs) – the precursors to the US Navy SEALs. Nine teams were established soon after, consisting of 150 enlisted men and 30 officers.