Implacable Foes

War in the Pacific,

Waldo Heinrichs and
Marc Gallicchio

Oxford University Press, New York, 2017, 728 pages

Lt. Col. Jesse McIntyre III, U.S. Army, Retired

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Cover Implacable Foes War in the Pacific, 1944–1945

Implacable Foes: War in the Pacific, 1944–1945 is a fascinating look at the last year in the Pacific theater of operations during World War II. It describes the complex challenges of economic reconversion, demobilization, redeployment, foreign policy, and public opinion faced by the United States in defeating a foe committed to fighting to the last man. The American victory over Japan, seemingly assured after the Battle of Midway in June 1942, would rely on two atomic bombs and the belated intervention of Japanese emperor Hirohito.

In a remarkably well-research volume, Waldo Heinrichs and Marc Gallicchio draw on a range of primary source material— personal accounts, U.S. records, and military correspondence—in providing an unprecedented view of the war in the Pacific. They begin with early 1944 as the balance shifted as American forces moved into unceasing offensive action that would take them to the Japanese homeland by summer 1945. Readers are given an up-front view of why the war in the Pacific was considered a special hell unlike any other theater.

The authors remind us that Japanese officials also understood that the war had entered another phase after 1943. The Japanese military doctrine abandoned its previous waterline defense in favor of mobile defense inland organized around fortified strong points. The overall objective would be to draw Allied forces into costly and time-consuming operations. Japanese training still emphasized the superiority of the warrior spirit but focused on a strategy of attrition and delay. Japanese officers became less willing to squander the lives of their men in suicidal banzai attacks, although this belief that all Japanese civilians should willingly give their lives for the emperor had become a fundamental principle of Japanese strategy.

The defending Japanese forces were not the only threat to Allied forces; the climate in the Pacific was a steady source of hardship and danger. Soldiers and marines suffered from a variety of insect and waterborne diseases that resulted in the highest noncombat-related casualty rates in the war. Malaria was by far the most devastating disease, causing more casualties than the Japanese. At some point, between 60 and 65 percent of soldiers serving in the South Pacific reported having malaria. Additionally, the vegetation and terrain favored the Japanese. Americans often found themselves conducting costly frontal assaults during island operations in which the only outcomes could be victory or death.

April 1945 began on a high note, bringing welcome news to the American home front. In Europe, Allied forces swept across the Rhine and plunged into Germany’s industrial heartland. Newspapers reported daily on the surrender or encirclement of large groups of German soldiers as Allied forces pushed for Berlin. In the Pacific, American landings on Okinawa were unopposed. Heinrichs and Gallicchio cite contemporary media reports of an unopposed landing and light Japanese resistance. Two weeks later, however, press reports stated that the American advance on Okinawa had stalled in the face of fierce Japanese resistance. The eighty-two-day-long battle would result in over forty-nine thousand casualties and serve as a grim foreboding of the invasion of the Japanese homeland that lay ahead.

Allied planners developed Operation Downfall for the proposed invasion of Japan. Commanded by Gen. Douglas MacArthur, the plan consisted of two parts: Operation Olympic and Operation Coronet. Olympic would start in November 1945 and culminate with the capture of the southernmost Japanese island, Kyushu. Kyushu would then serve as a staging area for Coronet, the invasion of the Kanto Plain near Tokyo, scheduled for March 1946. Allied planners envisioned both operations involving five million men and the largest concentrations of planes and ships used in a single operation. William Shockley, an American physicist, prepared a study for Secretary of War Henry Stimson’s staff that estimated that conquering Japan would cost 1.7 to 4 million American casualties, including 400,000 to 800,000 deaths, and 5 to 10 million Japanese fatalities.

The Japanese Imperial General Headquarters came to the realization after the battle of Leyte in December 1944 that the overall outcome of the war had been decided in favor of the United States. Japanese planners accurately anticipated that the Americans would intensify their air and naval operations throughout the Pacific theater and would seek to neutralize the Japanese homeland. They would continue to degrade Japanese strength while moving in range of invading Japan.

The Japanese General Staff developed Operation Ketsu-go, a defensive plan for its homeland whose intent was not to throw back an invasion but to make it so costly that the United States would be more willing to negotiate. Decrypted Japanese military messages indicated that Japanese planners had accurately determined Downfall’s landing sites on Kyushu and the Kanto Plain near Tokyo. The Japanese planned an all-out defense of Kyushu with a targeted completion date of June 1945. The Imperial General Headquarters and the General Army Headquarters had arrived at the conclusion that the Americans must be engaged relentlessly in a decisive battle on the beaches and in the coastal zones to prevent the Americans from establishing lodgments. The chief of the Naval General Staff told the Imperial Conference in June 1945 that he believed it possible to destroy nearly half of the enemy forces before they ever landed on the Japanese beaches.1

The authors artfully capture the challenge Downfall planners faced. Units currently in the Pacific would make the initial assaults in Olympic and Coronet. The incoming replacements would fill out the Olympic assault forces scheduled for November 1945 while units redeploying from Europe constituted the reserves and follow-on troops for Coronet. The intensity of fighting in the Philippines, Iwo Jima, and Okinawa required extensive infantry reconstitution of Army and Marine Corps divisions. Given the losses among his own troops as well as those of the marines at Iwo Jima, and with the battle of Okinawa underway, MacArthur expressed concern to Gen. George Marshall about the shortage of available veteran Pacific infantrymen for Operation Olympic, the upcoming invasion of Kyushu.

Exacerbating MacArthur’s manpower shortage was the War Department’s Demobilization Policy that discharged service members who had accrued eighty-five points based on months in service, months in service overseas, combat awards, and dependent children. This included a large number of combat-experienced infantrymen that were in the Pacific, thus reducing the available number of combat-experienced men required for Olympic.

A shipping crisis in the fall of 1944 through the winter of 1945 racked the American overseas supply system at the very moment when it was most overextended. Priority of shipping went to Europe in response to Germany’s offensive in the Ardennes and to bring relief supplies for European citizens facing a brutal winter. The shortage of available transports delayed the redeployment of European units and equipment back to the United States.

Heinrichs and Gallicchio illuminate the concerns of the redeploying soldiers, survivors of combat in the European theater, who now faced the grim prospect of invading the Japanese homeland. Among those was my father-in-law, Leonard Croft—a tank destroyer crewmember and veteran of the Ardennes, Hurtgen Forest, and Colmar Pocket—who found himself back at Fort Hood where he waited for redeployment to the Pacific. Redeploying soldiers would receive thirty days of leave and additional thirty days of training prior to redeploying. Army medical leaders expressed concern to Marshall that granting thirty days of leave to redeploying soldiers would result in large numbers of desertions.

Heinrichs and Gallicchio’s research counters a generation of revisionist scholars who assert the use of atomic weapons was to impress the Soviet Union or to exact revenge for Pearl Harbor. Gar Alperovitz, an American political economist and historian, concludes in The Decision to use the Atomic Bomb that President Harry Truman authorized the atomic bombings of Nagasaki and Hiroshima to send a message to the Soviet Union.2 Alperovitz argues that Japan by the summer of 1945 was essentially defeated. While Alperovitz is correct that Japan had no hope of winning the war, he fails in considering Japanese intentions in 1945.

Heinrich and Gallicchio’s research reveals that the United States possessed the capability of collecting information through Magic decrypts of Japanese diplomatic messages and Ultra decrypts of Japanese military messages. Analysis of the decrypted messages indicated that Japan remained unwilling to accept anything resembling unconditional surrender. Instead, Tokyo was employing diplomacy to avoid full consequences of defeat while simultaneously preparing for a bloody showdown on Kyushu.

Allied planners were alarmed at Ultra reports that indicate an increase of new Japanese units arriving on Kyushu that, if not checked, could have resulted in an attacker-to-defender ratio of one-to-one. Ultra reports also indicated an increase of Japanese aircraft being moved in range of Kyushu invasion beaches. Japanese military leaders had full intention of fighting to the last man.

Gen. Leslie Groves, director of the Manhattan Project, provided Truman an atomic bomb report that gave him hope that the war would be shortened without Operation Downfall. Possession of the atomic bomb provided Truman options and firmed his stance toward Japan. Truman was convinced that the bomb would make an invasion unnecessary. The report also alleviated concerns of the Navy that had been requesting an alternative to Downfall. The Japanese buildup on Kyushu strengthened the Navy’s inclination to question Downfall’s success probability, invasion casualty estimates, and Army readiness in time for Olympic. Adm. Raymond Spruance noted that the Army’s 77th Infantry Division and other Army divisions conducting operations in northern Luzon were in very poor shape.

The authors describe the anxious last days as intercepts of Japanese diplomatic and military traffic enabled Washington to watch the drama unfolding within the Japanese government. The dropping of two atomic bombs followed by the Soviet Union’s declaration of war left the Japanese stunned and demoralized. Tokyo remained defiant following the dropping of the second bomb on Nagasaki. War Minister Anami Korechika insisted that Japan would not consider surrendering unless the Allies agree to four conditions: preservation of the emperor and the imperial institution, no occupation of Japan, Japanese determination of who might be subjected to war-crime trials, and the right of the Japanese armed forces to disarm itself. He followed it up a day later that it would be better for the one hundred million Japanese to die as one than to agree to occupation of Japan. The sentiment was expressed by other senior military leaders.

Hirohito intervened and stated that Japan would accept terms of surrender as long as it did not removed his authority as a sovereign ruler. Dissidents in the imperial army attempted a coup in hope of preventing the emperor from issuing the surrender decree. The plotters planned to seize the imperial palace and destroy his recorded surrender message. It was quickly thwarted, and the plotters committed suicide in front of the palace.

Critics have questioned Truman’s decision to drop the atomic bomb. Truman made the right decision when one considers the bitter fighting of the Iwo Jima and Okinawa operations, Japanese intentions for Operation Ketsu-go, and projected Allied and Japanese casualties. My father, a naval aviator aboard the USS Enterprise; several uncles; and my father-in-law all would have participated in the invasion of the Japanese homeland. I am thankful they did not have to.

Implacable Foes: War in the Pacific 1944–1945 is superbly written. Heinrichs and Gallicchio’s extensive research makes it one of the most definitive studies of the final year of war in the Pacific. The authors’ inclusion of the key decision-makers, the inner turmoil of those leaders, and a detailed discussion of their motives help create vivid mental images of what was occurring behind the doors in Tokyo and Washington, D.C. This book depicts the challenges faced by the Truman administration. It is a must for both scholar and student alike interested in the war of the Pacific.


  1. K. Jack Bauer and Alan C. Coox, “Olympic vs Ketsu-go,” Marine Corps Gazette 49, no. 8 (August 1965), accessed 30 January 2018,
  2. Gal Alperovitz, The Decision to Use the Atomic Bomb (New York: Random House, 1995), 6.


Lt. Col. Jesse McIntyre III, U.S. Army, retired, is an assistant professor at the U.S. Army Command and General Staff College, Fort Leavenworth, Kansas. He holds a BA from the University of Missouri and an MA from Touro University. He served as the director for psychological operations policy, Office of Assistant Secretary of Defense for Special Operations/Low Intensity Conflict; psychological operations officer on the Department of the Army staff; and in a variety of special operations and infantry assignments. He also instructed at the U.S. Army John F. Kennedy Special Warfare School and Center.

March-April 2018