Admiral Chester W. Nimitz’s central Pacific offensive of 1943-1944 was a major component of the Allies’ “twin-axis” strategy to defeat Japan in World War II.

In late autumn, 1943, forces from the U.S. Navy, Marines, and Army, directed by Admiral Chester W. Nimitz in his capacity as commander in chief of the Pacific Fleet (CinCPac), embarked on an unprecedented island-hopping campaign against the Japanese in the central Pacific. Involving complicated amphibious operations against a series of fiercely defended strongholds, Nimitz’s offensive combined with operations conducted by General Douglas MacArthur MacArthur, Douglas
[p]MacArthur, Douglas;World War II in the southwest Pacific to produce a “twin-axis” advance that played a crucial role in the Allies’ ultimate victory over Japan in World War II. World War II (1939-1945)[World War 02];Pacific theater
World War II (1939-1945)[World War 02];central Pacific campaign
[kw]Central Pacific Offensive (Nov. 20, 1943-Nov. 27, 1944)
[kw]Offensive, Central Pacific (Nov. 20, 1943-Nov. 27, 1944)
World War II (1939-1945)[World War 02];Pacific theater
World War II (1939-1945)[World War 02];central Pacific campaign
[g]Pacific;Nov. 20, 1943-Nov. 27, 1944: Central Pacific Offensive[00990]
[g]Micronesia;Nov. 20, 1943-Nov. 27, 1944: Central Pacific Offensive[00990]
[c]World War II;Nov. 20, 1943-Nov. 27, 1944: Central Pacific Offensive[00990]
[c]Military history;Nov. 20, 1943-Nov. 27, 1944: Central Pacific Offensive[00990]
[c]Wars, uprisings, and civil unrest;Nov. 20, 1943-Nov. 27, 1944: Central Pacific Offensive[00990]
Nimitz, Chester W.
Spruance, Raymond A.
Mitscher, Marc A.
King, Ernest
Ozawa, Jisaburō

Nimitz’s central Pacific offensive represented a delayed implementation of War Plan Orange War Plan Orange , a contingency strategy for conflict with Japan developed by American military planners during the interwar period. In its final prewar version (1938), War Plan Orange provided for a drive by naval forces across the central Pacific involving the capture of islands—the Marshalls, Carolines, and Marianas—mandated to Japan after World War I. This was to be followed by the relief of the garrison defending the Philippines, which planners assumed the Japanese would attack, and a major fleet engagement, whose outcome would decide the conflict.

Once the United States entered World War II in December 1941, President Franklin D. Roosevelt’s Roosevelt, Franklin D.
[p]Roosevelt, Franklin D.;World War II military leadership[World War 02 military] commitment to a Europe-first strategy combined with Japan’s stunning victories—commencing with the attack on Pearl Harbor—to preclude an immediate central Pacific drive. However, once Allied forces halted Japanese expansion at the Battles of Coral Sea and Midway (May-June, 1942) and then seized the initiative at Guadalcanal and Papua (August, 1942-February, 1943), Admiral Ernest King, U.S. Fleet commander in chief (CominCh), began promoting a central Pacific offensive as the best means to maintain pressure on the Japanese in the short term and to achieve ultimate victory in the long term.

Advocated by King at the January 14-23 Casablanca Conference, a central Pacific offensive received formal approval at the May 11-25, 1943, Trident Conference Trident Conference (1943)
World War II (1939-1945)[World War 02];Allied planning meetings . At Trident, President Roosevelt, British prime minister Winston Churchill, and their respective military chiefs agreed that Nimitz should seize the Marshalls and Carolines while MacArthur continued operations in New Guinea and the Solomon Islands, with priority given to the central Pacific. Thus was born the “twin-axis” strategy.

On November 20, 1943, the central Pacific drive commenced when marines and soldiers invaded Butaritari (Makin) and Tarawa in the Gilbert Islands (Operation Galvanic) Operation Galvanic . They were supported by Admiral Raymond A. Spruance’s Central Pacific Force (which would become the Fifth Fleet in April, 1944). Not initially earmarked as an objective, the Gilberts, located twenty-five hundred miles west of Hawaii, became one when American planners concluded that invading the Marshalls would divert resources from MacArthur’s campaigns already under way and thus ordered Nimitz to make the Gilberts his first target.

Army forces secured Butaritari against tougher than anticipated resistance, while Tarawa Tarawa, Battle of (1943) produced one of the bloodiest battles in Marine Corps history. Lasting seventy-six hours, the Tarawa campaign witnessed the marines wipe out nearly the entire five-thousand-man Japanese garrison, suffering more than three thousand casualties, including more than one thousand dead, in the process. “Bloody Tarawa” shocked American leaders and the public, prompted a call for a congressional investigation, and demonstrated that U.S. forces had much to learn about amphibious operations.

From the Gilberts, Nimitz’s forces moved on to the Marshalls, an island group located six hundred miles northwest of Tarawa. Bypassing the eastern atolls, marines and soldiers, again supported by Spruance, landed at Kwajalein, Roi, and Namur, in the center of the chain, on January 31, 1944 (Operation Flintlock) Operation Flintlock . On February 17, in Operation Catchpole Operation Catchpole , they landed at Enewetak, at the chain’s western edge. Again encountering significant resistance, American forces completed both operations quickly (by February 21), inflicting more than twelve thousand casualties while suffering fewer than one thousand and demonstrating that they had digested the lessons of Tarawa.

While the Marshalls campaign unfolded, the Central Pacific Force neutralized Chuuk, the major anchorage for Japan’s Combined Fleet in the Caroline Islands. On February 17-18, Admiral Marc A. Mitscher’s Task Force 58 Task Force 58 launched a series of massive carrier-borne air strikes that destroyed 275 aircraft, sank 41 merchant ships and warships, and did tremendous damage to the base’s facilities. Mitscher’s raid had major implications for the future of the central Pacific drive, convincing Nimitz that Chuuk had been rendered useless and that the Carolines—originally slated to be the next target—could be bypassed in favor of an assault against the Marianas, located one thousand miles northwest of Enewetak and only twelve hundred miles southeast of Japan. As for the Japanese garrisons in the Carolines, they would be left to wither, cut off from any source of supplies and thus eliminated as a military factor.

U.S. troops in the 165th Infantry wade ashore under fire during the bloody Battle of Tarawa.

(National Archives)

Operation Forager Operation Forager , the attack on the Marianas, began June 15, 1944, when two marine divisions, supported by an army division in reserve, invaded Saipan. Recognizing the Marianas’ strategically significant location and the potentially devastating impact of their loss, Saipan’s thirty-two-thousand-man garrison conducted a well-executed defense designed to inflict maximum casualties while delaying the American advance. Meanwhile, the Japanese navy undertook an operation, codenamed A-Go Operation A-Go[Operation A Go] , to destroy the Central Pacific Force and thereby leave U.S. ground forces without naval and air support.

Directed by Admiral Jisaburō Ozawa, the A-Go offensive ended in disaster when Mitscher’s Task Force 58, having ascertained enemy intentions, intercepted the Japanese. The resulting Battle of the Philippine Sea Philippine Sea, Battle of the (1944) (June 19-20) struck an irreversible blow to Japan’s naval air arm, costing it 476 aircraft, 445 pilots, and 3 carriers it could not replace. On Saipan itself, the fighting ground on for three bloody weeks, until July 9. The Americans suffered more than sixteen thousand casualties. Japanese dead numbered more than thirty thousand, including an untold number of civilians who committed suicide, rather than surrender, by throwing themselves off the steep cliffs on the island’s northern end.

Two U.S. officers plant the American flag on the beach at Guam, one of the islands taken during the central Pacific offensive.

(National Archives)

Saipan’s fall prompted the resignation (July 18) of Hideki Tojo Tojo, Hideki , Japan’s prime minister and war minister since 1941, who had been instrumental in the decision to go to war against the United States. Tojo’s fall could not, however, reverse the tide. On July 21, U.S. forces continued the Marianas campaign by invading Guam, following up on July 24 with an assault on Tinian. As had been the case on Saipan, Japanese defenders fought ferociously, but they could only delay the inevitable. American forces declared Tinian secure on August 1, followed by Guam on August 10. Tinian’s conquest provided the U.S. Twenty-First Bomber Command with bases from which its newly developed B-29 Superfortresses B-29 Superfortress[B 29 Superfortress] would conduct, beginning in November, a devastating strategic bombing campaign against Japan.

Nimitz’s drive in the central Pacific during 1944 concluded with Operation Stalemate Operation Stalemate , comprising invasions of Peleliu Peleliu, Battle of (1944) (September 15) and Angaur Angaur, Battle of (1944) (September 17) in the Palau Islands. Angaur was secured by October 21, and Peleliu was under Allied control by November 27, marking the successful conclusion of the central Pacific offensive. Designed to secure air and naval bases from which MacArthur’s impending invasion of the Philippines could be supported, Peleliu and Angaur proved bloody affairs for the marines and soldiers who had to overcome a dug-in, determined enemy, difficult terrain, and excessive heat that occasionally reached 115 degrees Fahrenheit. Marine casualties on Peleliu alone numbered more than sixty-five hundred, while army losses exceeded thirty-two hundred total, with most occurring on Anguar. While the victories on Peleliu and Angaur did allow the Americans to establish a major fleet anchorage at Ulithi, bases in the Palaus played no role in MacArthur’s invasion of Leyte, a development leading some scholars to conclude that Operation Stalemate was unnecessary.

The American drive across the central Pacific, between November 20, 1943, and November 27, 1944, witnessed U.S. forces perfect their conduct of amphibious operations, as they pierced the defensive perimeter established by the Japanese to protect the vast empire they had conquered in the opening months of the Pacific war. Admiral Nimitz’s advance inflicted serious damage on Japan’s military power, depriving it of militarily significant bases, annihilating entire garrisons while isolating others, and eliminating Japanese naval air power. Simultaneously, the central Pacific offensive brought the United States bases in the Marianas from which it could launch a strategic bombing campaign against the Japanese home islands and put Nimitz’s forces in position to undertake the future invasions of Iwo Jima (February, 1945) and Okinawa (April, 1945). World War II (1939-1945)[World War 02];Pacific theater
World War II (1939-1945)[World War 02];central Pacific campaign

• Carter, Worrall Reed. Beans, Bullets, and Black Oil: The Story of Fleet Logistics Afloat in the Pacific During World War II. Newport, R.I.: Naval War College Press, 1998. An important analysis of the complicated logistics involved in the central Pacific offensive.
• Gatchel, Theodore. “The Shortest Road to Tokyo,” in The Pacific War Companion, edited by Daniel Marston. Oxford, England: Osprey, 2005. Offers a concise analysis and overview of the central Pacific campaign, emphasizing the difficulties Nimitz had to overcome in coordinating a complicated undertaking.
• Isely, Jeter A., and Philip A. Crowl. The U.S Marines and Amphibious War: Its Theory and Practice in the Pacific. Princeton, N.J.: Princeton University, 1951. Older but indispensable for understanding amphibious operations in the central Pacific.
• Miller, Edward S. War Plan Orange. Annapolis, Md.: Naval Institute Press, 1991. Traces the evolution of America’s pre-World War II planning for conflict with Japan, which included the concept of a naval drive across the central Pacific.
• Sledge, E. P. With the Old Breed: At Peleliu and Okinawa. New York: Oxford University Press, 1990. Gripping memoir of a U.S. Marine who fought on Peleliu; gives the reader a sense of what operations in the central Pacific were like for those who did the fighting.

World War II: Pacific Theater

Bombing of Pearl Harbor

Japan Begins Attacks on Southeast Asia

Japan Invades the Philippines

Battle of the Coral Sea

Battle of Midway

Battle of Guadalcanal

Casablanca Conference

Battle of the Philippine Sea

Battle for Leyte Gulf

American Flag Is Raised at Iwo Jima