Yukiko Koshiro presents a bold reinterpretation of World War II in Asia and the Pacific, which she renames the Eurasian-Pacific War, focusing on the relationship between Japan and the Soviet Union. A critic of both Japanese militarism and Western imperialism, she pushes back against a narrative which portrays the United States as a defender of Asia, rather than an imperialistic power, a narrative she says was produced in the immediate postwar period. She also wishes to dismantle the idea that the Japanese government leaders during the last years of the conflict were diehard fanatics “incapable of devising and pursuing coherent war goals”, who needed the “shock therapy” of the atomic bombs to bring them to their senses. Instead, she presents the leaders as canny strategists who were willing to sacrifice over 200,000 Japanese soldiers and civilians in Manchuria as part of a plan to achieve a postwar balance of power in Asia through a Soviet invasion.

Koshiro has marshalled an army of documents and testimonies, delivering novel and unexpected insights on a wide variety of subjects, and producing a lively narrative. Unfortunately, in the laudable pursuit of breaking down old assumptions and providing new insights, she too often makes assertions that go beyond the evidence she employs. In the end, while she succeeds in casting Japan's wartime Soviet policy in a new light, her central thesis is marred by overreach.

The first two chapters provide convincing evidence that Russia was more on the minds of the Japanese during the prewar era than has been commonly thought. She favorably compares the experiences of Russian settlers in the Japanese empire to Americans, demonstrating that the wide range of Russians in the empire were not as obsessed with race, and therefore mixed with and influenced Japanese more effectively than the more wealthy and exclusionary Americans.

In Chapter 3 Koshiro again turns conventional wisdom on its head when she describes how the Japanese government and military planners in the 1943–1945 period respected the Chinese Communist Party for its ability to win popular support, and were more aware of the CCP's independence vis-à-vis the Soviet Union than has been previously recognized. She then, however, moves towards an unsubstantiated claim that the Japanese government decided to “recognize” the CCP in the summer of 1944, and that it was moving towards an alliance with the CCP against the Guomindang-Anglo-American alliance. She ascertains that the Japanese government did decide on a policy to treat the Yan'an CCP regime as a separate entity from the Guomindang regime in Chongqing, and curtailed the use of terms like “destruction of communism” that could potentially drive the GMD and CCP towards closer cooperation. But she presents no convincing evidence of any plans to actually recognize the CCP regime's legitimacy as a sovereign government, or make diplomatic overtures towards the CCP regime.

Chapters 5 through 7 are the heart of the book, covering the Japan-Soviet relationship from the start of the Pacific War in 1941 to Japan's surrender in August 1945. Koshiro shows that as Japan neared defeat, planners envisioned the Soviet Union as coming to play a balancing role against American hegemony in postwar Asia, thereby giving Japan a chance to play the two sides against each other and regain some degree of international influence. They removed key units from the Kwantung Army not because they trusted that the Soviet Union would remain neutral. Rather, they correctly predicted that the Soviets would invade Manchuria after the defeat of Germany, and pulled as many troops out of its indefensible north as they could so that they could focus on defending a perimeter of southern Korea and the Japanese archipelago. Koshiro demonstrates these points effectively, largely through using the previously underutilized Army War Operations Plans Division's Kimitsu Sensō Nisshi, which Division officers withheld from occupation forces by hiding them in metal cylinders under the house of one of the officers. But she then goes on to claim that the Japanese leaders purposely delayed their surrender in 1945 until a Soviet entry into the war. By stalling a surrender to the United States until after the Soviet Union could amass forces in Siberia and invade Manchuria and Korea, she claims, Japan was guaranteeing itself a place in a multi-polar postwar Asia. She alleges Japan had no intention of fighting an American invasion of its home islands – it would surrender as soon as such an invasion began, or as soon as the Soviets invaded Manchuria. Koshiro is not successful in proving these more difficult points. She takes a variety of vague phrases from the Kimitsu Sensō Nisshi and other sources, and imbues them with meaning not apparent from a simple reading.

The centerpiece of Koshiro's claim that planners looked forward to a future Soviet Union presence is an April 29, 1945 opinion paper by Colonel Tanemura Sakō, a leading member of the Army War Operations Plans Division (as Tanemura is the key witness for Koshiro's positions, I wish she had provided a more thorough discussion of his background and role within the Army). Tanemura identifies the British and Americans as Japan's ultimate enemy, and keeping them out of Asia was the state's primary goal. To achieve this, Japan should appeal to the Soviet Union to intervene on their behalf with the Western powers. To induce this intervention, Tanemura proposed giving up all of Japan's possessions outside the home islands, even including the Ryukyu Islands. The Soviet Union would not completely dominate the continent, he indicated, as the CCP would act as an independent, balancing power. Koshiro misrepresents the central quote of this document, however, in a way that supports her position. She translates Tanemura as, “If, in the process of negotiating with the Soviets, they force us to begin the path toward ending the war by either offering mediation or using intimidation by hitting hard our weak spot, we should be prepared to comply with it” (italics mine). “[B]e prepared to comply with it” appears to mean Japan giving up its overseas territories. The words, “by hitting hard our weak spot”, however, do not appear in the document. Perhaps Koshiro thought that the phrase was implied in the word dōkatsu (threaten, intimidate, blackmail), or perhaps it was simply an error, but the unwarranted addition of this phrase works to support the thesis that planners like Tanemura anticipated an attack on a purposely hollowed out Kwantung Army in Manchuria, which they intended to sacrifice in the name of postwar advantage. In the end, Koshiro fails to convincingly prove this thesis.

Imperial Eclipse is a valuable work which encourages its readers to re-examine pre-existing assumptions. I applaud boldness and innovation in scholarship, and I appreciate a clear authorial perspective and voice. In this case, however, I believe boldness outstripped impartiality.