[8] Previous landings had met little to no initial resistance,[9][a] 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.

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.

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.

[11] 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.

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.

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.

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.

United States Fifth Fleet[15] Admiral Raymond A. Spruance in heavy cruiser Indianapolis V Amphibious Corps[16] Major General Holland M. "Howlin' Mad" Smith, USMC Gilbert Islands defense forces[17] Rear Adm. Keiji Shibasaki (KIA 20 Nov) Approx.

[20][21] The supporting naval bombardment lifted, and the Marines started their attack from the lagoon at 09:00, thirty minutes later than expected, but found the tide had not risen enough to allow their shallow draft Higgins boats to clear the reef.

[14] The communication lines that the Japanese installed on the island had been laid shallow and were destroyed in the naval bombardment, effectively preventing commander Keiji Shibazaki from exercising direct control of his troops.

In mid-afternoon, he and his staff abandoned the command post at the northeast end of the airfield to allow it to be used to shelter and care for the wounded, and he prepared to move to the south side of the island.

The Marines brought a battery of 75 mm pack howitzers ashore, unpacked them and set them up for action for the next day's fight, but most of the second wave was unable to land.

With the Marines holding a thin line on the island, they were commanded to attack Red Beach 2 and 3 and push inward and divide the Japanese defenders into two sections, expanding the bulge near the airfield until it reached the southern shore.

[29] The third day of battle consisted primarily of consolidating existing lines along Red 1 and 2, an eastward thrust from the wharf, and moving additional heavy equipment and tanks ashore onto Green Beach at 08:00.

By late afternoon they had reached the eastern end of the airfield and had formed a continuous line with the forces that landed on Red 3 two days earlier.

At 08:00 3rd Battalion, 6th Marines (3/6) under the command of Lieutenant Colonel McLeod attacked, Jones' 1/6 having been pulled off the line after suffering 45 killed and 128 wounded in the previous night's fighting.

Major Hewitt Adams led an infantry platoon supported by two pack howitzers from the lagoon into the Japanese positions to complete the encirclement.

On the eastern end of the island L Company continued to advance, bypassing pockets of resistance and leaving them to be cleared out by tanks, engineers and air support.

[40] The heavy casualties suffered by the United States at Tarawa[41] sparked public protest, where headline reports of the high losses could not be understood for such a small and seemingly unimportant island.

General Holland Smith, commander of the V Amphibious Corps who had toured the beaches after the battle, likened the losses to Pickett's Charge at Gettysburg.

Back in Washington, newly appointed Marine Corps Commandant Alexander Vandegrift, the widely respected and highly decorated veteran of Guadalcanal, reassured Congress, pointing out that "Tarawa was an assault from beginning to end".

A New York Times editorial on 27 December 1943 praised the Marines for overcoming Tarawa's rugged defenses and fanatical garrison and warned that future assaults in the Marshalls might well result in heavier losses.

[45] With the Marines at Tarawa contained scenes of American dead so disturbing that the decision of whether to release it to the public was deferred to President Franklin D. Roosevelt, who approved it.

The 2nd Marine Division remained in Hawaii for six months, refitting and training, until called upon for its next major amphibious landing, the Battle of Saipan in the Marianas in June 1944.

[46] The American casualties at Tarawa resulted from several contributing factors, among which were the miscalculation of the tide and the height of the obstructing coral reefs, the operational shortcomings of the landing craft available, the inability of the naval bombardment to weaken the defenses of a well entrenched enemy, and the difficulties of coordinating and communicating between the different military branches involved.

[47] The failures of the Tarawa landing were a major factor in the founding of the Underwater Demolition Teams (UDT) - the precursor of the current U.S. Navy SEALS.

[attribution needed][48] War Correspondent Robert Sherrod wrote: Last week some 2,000 or 3,000 United States Marines, most of them now dead or wounded, gave the nation a name to stand beside those of Concord Bridge, the Bonhomme Richard, the Alamo, Little Bighorn, and Belleau Wood.

"[51] The remains of 36 Marines, including 1st Lieutenant Alexander Bonnyman Jr., were interred in a battlefield cemetery whose location was lost by the end of the war.