The prize, sponsored by the Daily Yomiuri, Japan's largest newspaper, recognizes the best book published in Japan in the past year in the fields of politics, economics, and history. It includes a monetary award of approximately $28,000.
Earlier in 2006, Hasegawa received the Robert Ferrell Book Prize, the most prestigious award given by the Society of Historians for Foreign Relations for his multiarchival contribution to research on the end of the war. The New York Times called his book "a brilliant and definitive study of American, Soviet, and Japanese records of the last week of the war."
While many Americans believe that World War II ended in the blinding flashes of the atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki in August of 1945, historians have hotly debated whether the American use of the atomic bombs was justified. With their exclusive focus on the atomic bombings, however, historians have not fully examined other important factors the entry of the Soviet Union into the war and a confused and divided Japanese leadership.
Examining in detail the deliberations of the Japanese leadership immersed in squabbling over how to end the war with the emperor system intact, Hasegawa claims the bombs were not the most decisive factor in Japan's decision to end the war. Only when the Soviets, jockeying with the United States for post-war influence in Asia, declared war and invaded Japanese-held Manchuria did the Japanese leadership capitulate to prevent falling under Soviet dominance.