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World War II Pacific: Advancing Across the Pacific

Island Hopping


World War II Pacific: Advancing Across the Pacific

Marines storm Tarawa, Gilbert Islands, 1943.

Photograph Courtesy of the National Archives & Records Administration
World War II Pacific: Advancing Across the Pacific

The carrier Zuikaku (center) and two destroyers under attack by U.S. Navy carrier aircraft, June 20, 1944.

Photograph Courtesy of the US Naval Historical Center
World War II Pacific: Advancing Across the Pacific

Gen. Douglas MacArthur and party lands at Palo Beach, Leyte, October 20, 1944.

Photograph Courtesy of the US Army
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"Island Hopping"

In mid-1943, the Allied command in the Pacific began Operation Cartwheel which was designed to isolate the Japanese base at Rabaul on New Britain. The key elements of Cartwheel involved Allied forces under General Douglas MacArthur pushing across northeastern New Guinea, while naval forces secured the Solomon Islands to the east. Rather than engage sizable Japanese garrisons, these operations were designed to cut them off and let them "whither on the vine." This approach of bypassing Japanese strong points, such as Truk, was applied on a large scale as the Allies devised their strategy for moving across the central Pacific. Known as "island hopping," US forces moved from island to island, using each as a base for capturing the next. As the island hopping campaign began, MacArthur continued his push in New Guinea while other Allied troops were engaged in clearing the Japanese from the Aleutians.


The initial move of the island hopping campaign came in the Gilbert Islands when US forces struck Tarawa Atoll. The capture of the island was necessary as it would allow the Allies to move on to the Marshall Islands and then the Marianas. Understanding its importance, Admiral Keiji Shibazaki, Tarawa's commander, and his 4,800-men garrison heavily fortified the island. On November 20, 1943, Allied warships opened fire on Tarawa and carrier aircraft began striking targets across the atoll. Around 9:00 AM, the 2nd Marine Division began coming ashore. Their landings were hampered by a reef 500 yards offshore that prevented many landing craft from reaching the beach. After overcoming these difficulties, the Marines were able to push inland, though the advance was slow. Over the next three days, US forces succeeded in taking the island after brutal fighting and fanatical resistance from the Japanese. In the battle, US forces lost 1,001 killed and 2,296 wounded. Of the Japanese garrison, only seventeen Japanese soldiers remained alive at the end of the fighting along with 129 Korean laborers.

Kwajalein & Eniwetok

Using the lessons learned at Tarawa, US forces advanced into the Marshall Islands. The first target in the chain was Kwajalein. Beginning on January 31, 1944, the islands of the atoll were pummeled by naval and aerial bombardments. These were followed by landings carried out by the 4th Marine Division and the 7th Infantry Division. These attacks easily overran the Japanese defenses and the atoll was secured by February 3. As at Tarawa, the Japanese garrison fought to nearly the last man, with only 105 of nearly 8,000 defenders surviving.

As US amphibious forces sailed northwest to attack Eniwetok, the American aircraft carriers were moving to strike the Japanese anchorage at Truk Atoll. A principal Japanese base, US planes struck the airfields and ships at Truk on February 17-18, sinking three light cruisers, six destroyers, over twenty-five merchantmen, and destroying 270 aircraft. As Truk was burning, Allied troops began landing at Eniwetok. The islands of the atoll were captured on February 23, after a brief, but sharp battle. With the Gilberts and Marshalls secure, US commanders began planning for the invasion of the Marianas.

Saipan & the Battle of the Philippine Sea

Comprised primarily of the islands of Saipan, Guam, and Tinian, the Marianas were coveted by the Allies as airfields there would place the home islands of Japan within range of bombers such as the B-29 Superfortress. At 7:00 AM on June 15, 1944, US forces began landing on Saipan after a heavy naval bombardment. Fighting their way ashore, they met determined resistance from 31,000 defenders led by Lt. General Yoshitsugu Saito. Understanding the importance of the islands, Admiral Soemu Toyoda, commander of the Japanese Combined Fleet, dispatched Vice Admiral Jisaburo Ozawa to the area with five carriers to engage the US fleet.

The result of Ozawa's arrival was the Battle of the Philippine Sea which pitted his fleet against seven American carriers led by Admiral Raymond Spruance and Admiral Marc Mitscher. Fought June 19-20, American aircraft sank the carrier Hiyo, while the submarines USS Albacore and USS Cavalla sank the carriers Taiho and Shokaku. In the air, American aircraft downed over 600 Japanese aircraft while only losing 123 of their own. The aerial battle proved so one-sided that US pilots referred to it as "The Great Marianas Turkey Shoot." With only two carriers and 35 aircraft remaining, Ozawa retreated west, leaving the Americans in firm control of the skies and waters around the Marianas.

On Saipan, the Japanese fought tenaciously and slowly retreated into the island's mountains and caves. As US troops gradually forced the Japanese out, the island's civilians, who had been convinced that the Americans were barbarians, began committing mass suicide by jumping from the island's cliffs. Lacking supplies, Saito organized a final banzai attack for July 7. Beginning at dawn, it overran two American battalions before it was contained and defeated. Two days later, Saipan was declared secure. The battle was the costliest to date for American forces with 14,111 casualties. Almost the entire Japanese garrison of 31,000 was killed, including Saito who committed suicide.

Guam & Tinian

With Saipan taken, US forces moved down the chain, coming ashore on Guam on July 21. Landing with 36,000 men, the 3rd Marine Division and 77th Infantry Division drove the 18,500 Japanese defenders north until the island was secured on August 8. Only 485 prisoners were taken. As fighting was occurring on Guam, American troops landed on Tinian. Coming ashore on July 24, the 2nd and 4th Marine Divisions took the island after six days of combat. Though the island was declared secure, several hundred Japanese held out in the Tinian's jungles for months. With the Marianas taken, construction began on massive airbases from which raids against Japan would be launched.

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