The Battle of Tarawa was fought on 20–23 November 1943 between the United States and Japan on Tarawa Atoll in the Gilbert Islands, now part of the Republic of Kiribati but then a Japanese-occupied British colony. The battle was part of Operation Galvanic, the U.S. invasion of the Gilberts, and ended in a decisive American victory. Nearly 6,400 Japanese, Koreans, and Americans died during the battle, mostly on and around the small island of Betio, in the extreme southwest of Tarawa Atoll. At the time, Betio was only 118 hectares (290 acres).
The Battle of Tarawa was the first American offensive in the critical Central Pacific region. It was also the first time in the Pacific War that the United States faced serious Japanese opposition to an amphibious landing. Previous landings had met little to no initial resistance, but on Tarawa the 4,500 Japanese defenders were well supplied and well prepared, and they fought almost to the last man, exacting a heavy toll on the United States Marine Corps.
To set up forward air bases capable of supporting operations across the Central Pacific, to the Philippines, and toward Japan itself, the U.S. planned to take the Mariana Islands. The Marianas were heavily defended. Naval doctrine of the time held that in order for amphibious landings to succeed, land-based aircraft would be required to weaken defenses and protect the invasion forces on the islands being invaded. The nearest islands capable of supporting such an American effort on the Marianas were the Marshall Islands. Taking the Marshalls would provide the base needed to launch an offensive on the Marianas, but the Marshalls were cut off from direct communications with Hawaii by a Japanese garrison and air base on the small island of Betio, on the western side of the atoll of Tarawa in the Gilbert Islands. Thus, in order to eventually launch an invasion of the Marianas, American strategists believed that the Japanese garrison and airfield on Tarawa would first need to be neutralized.
Following the completion of the Guadalcanal campaign, the 2nd Marine Division had been withdrawn to New Zealand for rest and recuperation. Losses were replaced, and the men were given a chance to recover from malaria and other illnesses that had weakened them during the fighting in the Solomons. On 20 July 1943, the Joint Chiefs of Staff directed Admiral Chester W. Nimitz to prepare plans for an offensive operation in the Gilbert Islands. In August, Admiral Raymond A. Spruance flew to New Zealand to meet with the new commander of the 2nd Marine Division, General Julian C. Smith, and initiate the planning of the invasion with the division's commanders.
Located about 2,400 miles (3,900 km) southwest of Pearl Harbor, Betio is the largest island in the Tarawa Atoll. The small, flat island lies at the southernmost reach of the lagoon and was the base of the majority of the Japanese troops. Shaped roughly like a long, thin triangle, the tiny island is approximately 2 miles (3.2 km) long. It is narrow, being only 800 yards (730 m) wide at its widest point. A long pier was constructed jutting out from the north shore, onto which cargo ships could unload while anchored beyond the 500-metre (550 yd)-wide shallow reef which surrounded the island. The northern coast of the island faces into the lagoon, while the southern and western sides face the deep waters of the open ocean.
Following Colonel Evans Carlson's diversionary raid on Makin Island in August 1942, the Japanese command was made aware of the vulnerability and strategic significance of the Gilbert Islands. The 6th Yokosuka Special Naval Landing Force reinforced the island in February 1943. In command was Rear Admiral Tomonari Saichirō (友成 佐市郎), an experienced engineer who directed the construction of the sophisticated defensive structures on Betio. Upon their arrival, the 6th Yokosuka became a garrison force, and the unit's identification was changed to the 3rd Special Base Defense Force. Tomonari's primary goal in the Japanese defensive scheme was to stop the attackers in the water or pin them on the beaches. A tremendous number of pillboxes and firing pits were constructed, with excellent fields of fire over the water and sandy shore. In the interior of the island was the command post and several large shelters designed to protect defenders from air attack and bombardment. The island's defenses were not set up for a battle in depth across the interior. The interior structures were large and vented but did not have firing ports. Defenders were limited to firing from the doorways.
The Japanese worked intensively for nearly a year to fortify the island. To aid the garrison in the construction of the defenses, the 1,247 men of the 111th Pioneers, similar to the Seabees of the U.S. Navy, along with the 970 men of the Fourth Fleet's construction battalion, were brought in. Approximately 1,200 of the men in these two groups were Korean laborers.
The garrison was made up of forces of the Imperial Japanese Navy. The Special Naval Landing Force was the marine component of the IJN and were known by U.S. intelligence to be more highly trained, better disciplined, more tenacious and to have better small unit leadership than comparable units of the Imperial Japanese Army. The 3rd Special Base Defense Force assigned to Tarawa had a strength of 1,112 men. They were reinforced by the 7th Sasebo Special Naval Landing Force, with a strength of 1,497 men. It was commanded by Commander Takeo Sugai. This unit was bolstered by 14 Type 95 light tanks under the command of Ensign Ohtani.
A series of 14 coastal defense guns, including four large Vickers 8-inch guns purchased during the Russo-Japanese War from the British, were secured in concrete bunkers around the island to guard the open water approaches. It was thought these big guns would make it very difficult for a landing force to enter the lagoon and attack the island from the north side. The island had 500 pillboxes or "stockades" built from logs and sand, many of which were reinforced with cement. Forty artillery pieces were scattered around the island in various reinforced firing pits. An airfield was cut into the bush straight down the center of the island. Trenches connected all points of the island, allowing troops to move under cover when necessary to wherever they were needed. As the command believed their coastal guns would protect the approaches into the lagoon, an attack on the island was anticipated to come from the open waters of the western or southern beaches. Rear Admiral Keiji Shibazaki, an experienced combat officer from the campaigns in China, relieved Tomonari on 20 July 1943 in anticipation of the coming fight. Shibazaki continued the defensive preparations right up to the day of the invasion. He encouraged his troops, saying "it would take one million men one hundred years" to conquer Tarawa.
Admiral Raymond A. Spruance in heavy cruiser Indianapolis
Fifth Amphibious Force ("V 'Phib")
Rear Admiral Richmond Kelly Turner in battleship Pennsylvania
Northern Attack Force (Task Force 52 – Makin)
embarking 27th Infantry Division (Army) (Major General Ralph C. Smith)
Southern Attack Force (Task Force 53 – Tarawa)
Vice Admiral Harry W. Hill in battleship Maryland
embarking 2nd Marine Division (Major General Julian C. Smith)
Major General Holland M. "Howlin' Mad" Smith, USMC