On 1 August 1940, the newly appointed Japanese foreign minister Matsouka Yōsuke gave a radio speech in which he explained the shift in policy undertaken by the recently formed government of Prime Minister Konoe Fumimaro. He declared that "the essence of our country's foreign policy must focus on the establishment of a Greater East Asia Co-Prosperity Sphere that centers on Japan, Manchukuo, and China" (40), thus giving a label to the various war aims that underlay Japanese strategy until their surrender in September 1945. Yet as Jeremy Yellen (Chinese Univ. of Hong Kong) explains in his new book,[1] the Co-Prosperity Sphere was not simply a synonym for Japan's wartime empire but a transnational project for restructuring the region that involved local elites in the territories Japan seized from the Western empires.

Yellen stakes out his position early in the book by addressing the historiography of his subject. Noting the various ways the Co-Prosperity Sphere has been interpreted, he dismisses both the "orthodox" view of it as a fig leaf for Japanese imperialism and revisionist interpretations of it as embodying a pan-Asiatic movement or crusade to liberate the region from Western domination. Instead, he adopts a comparative approach that treats the Co-Prosperity Sphere as an evolving project that, while driven by Japanese policymakers, incorporated the anti-colonial goals of indigenous political figures in Southeast Asia. He conducts his analysis from the perspectives of both the policymakers in Japan and "patriotic collaborators" in the Philippines and Burma pursuing their own political ends.

Both narratives stress the element of expediency. While Yellen acknowledges the ideological roots of the Co-Prosperity Sphere in post-World War I Pan-Asianist thinking, he argues that the catalytic agent was the German conquest of Western Europe in spring 1940. That is, the assertion of Japan's interests in Southeast Asia was directed not just at the British and the Americans, but at the Germans as well:

Though Matsouka served as foreign minister for less than a year, he was both an advocate of the Co-Prosperity Sphere and an architect of the Tripartite Pact with Germany and Italy, which Yellen sees as a reassertion of old-style sphere-of-influence diplomacy. Japan attempted to dominate East and Southeast Asia through negotiations with the Soviet Union and the United States as well as actions like arbitrating the border crisis between Thailand and French Indochina. Ultimate success, however, "depended upon a string of improbable foreign policy successes that brooked no failure" (50); Matsouka failed to win American acquiescence in Japan's regional ambitions; this and his calls to attack the Soviet Union led to his ouster in June 1941. The Co-Prosperity Sphere concept nonetheless survived his departure, thanks to its adoption in a new form by the military as a Japanese-dominated source of materials for their war economy.

This reconceptualization of the Co-Prosperity Sphere soon failed as well, partly for lack of sufficient ideological buttressing. This changed with the start of the Pacific War, which required Japan to clearly define its war aims and led to the formation of a council to create a "Fundamental Policy" and the establishment of a Greater East Asia Ministry in September 1942. Though both were eclipsed by the demands of war, they played a role in founding local regimes in the aftermath of Japanese conquest.

Yellen next shifts to the newly occupied regions of the Philippines and Burma, detailing how the vision of the Co-Prosperity Sphere played out in practice. Many nationalists in both places saw it as a means of attaining independence as the shifting fortunes of war forced Japan to win their cooperation. In November 1943, the Greater East Asia Conference in Tokyo produced a "Pacific Charter" emphasizing mutual cooperation. Though efforts to follow through on such collaboration were overtaken by the realities of the war, Yellen notes that local nationalists were able to leverage Japan's Co-Prosperity Sphere for greater autonomy, paving the way for their postwar independence.

Given the enormous literature on the Second World War, it is surprising that Yellen's book is the first detailed English-language study of Japanese war aims and the Co-Prosperity Sphere.[2] He has filled a gap in the historiography with a well argued analysis grounded in extensive archival research (conducted on three continents) and a broad range of the relevant English and Japanese secondary literature. Unfortunately, his argument is hampered by a degree of confirmation bias. His concentration on the Philippines and Burma certainly allows him to make interesting points regarding two colonies with relatively advanced nationalist movements and expectations of independence in their near future. But, as he himself acknowledges, neither possessed the raw materials that Japanese leaders most desired. That is, Yellen focuses on the two colonies most likely to fit his interpretation of the Co-Prosperity Sphere. Had he examined instead such resource-rich colonies as Malaya or the Dutch East Indies, he might have better addressed the factors that have led other scholars to interpret the Co-Prosperity Sphere differently.

This criticism notwithstanding, Jeremy Yellen has made a notable contribution to the historical literature on the Pacific War in eastern Asia. Students and specialists alike will find his book to be a valuable resource and, hopefully, a springboard for further research into a lamentably understudied subject of great significance for postwar development of the region.