The Dai Tôa Kyôeiken, or "Greater East Asia Co-Prosperity Sphere," was the name of the ideological construct used by the Japanese Empire to justify its conquests in Southeast Asia during World War II.
Prior to the Pacific War, Japan had long justified its imperialist expansion in terms of dôshu and dôbun, or "common race" and "common culture." By acquiring Taiwan in 1895, annexing Korea in 1910, and conquering Manchuria and northern China in the 1930s, Japan was projecting its dominance over a group of peoples that shared a common writing system, common religious and philosophical traditions, and common physical features.
But as the Japanese war machine pushed into Southeast Asia in the summer of 1940, the old ideology of uniting Japan with its "racial and cultural brothers" became increasingly difficult to apply to peoples who had little or no cultural heritage in common with the Japanese, and often looked quite different from Northeast Asians. Thus it was that in a radio speech on June 29, 1940, Japanese foreign minister Arita Hachiro first spoke of the idea of a "co-prosperity sphere" that would add economic and geographic ties to racial and cultural bonds as justification for Japanese expansion, declaring:
"In order to realize world peace, it seems to be the most natural step that peoples who are closely related to one another geographically, racially, and economically should first form a sphere of their own for coexistence and co-prosperity and establish peace and order within that sphere, and at the same time secure a relationship of common existence and prosperity with other spheres. . . . The countries of East Asia and the regions of the South Seas are geographically close, historically, racially, and economically very closely related to each other. They are destined to cooperate and minister to one another's needs for their common well-being and prosperity, and to promote peace and progress in their regions. The unification of all these regions into a single sphere on the basis of common existence and assuring thereby the stability of that sphere is, I think, a natural conclusion."
Although it was actually Arita's successor as foreign minister Matsuoka Yôsuke
who first used the full term "Greater East Asia Co-Prosperity Sphere" in a speech in early August, it was this speech by Arita that first proposed a geographic "sphere" based on economic "co-prosperity."
The idea of Co-Prosperity Sphere was a thinly veiled jab at the hypocrisy of the "civilizing mission" of Western imperialism, with the term "co-prosperity" carefully chosen to suggest a new economic order in which all nations would benefit, as opposed to the extractive economies of the Western colonial order in which the economic benefit flowed only one way, straight into the coffers of the Western powers.
The Co-Prosperity Sphere also had the added appeal of placing Japan at the forefront of the creation of a new world order. The Japanese had long had an inferiority complex resulting from their perceived position as "late modernizers" who were always following in the footsteps of the Western powers and trying to copycat their cultural and technological achievements. In the words of historian Peter Duus, the ideology of the Greater East Asia Co-Prosperity Sphere allowed the Japanese to view themselves as "leaping from the baggage train of history into its vanguard"1
At first glance, it is tempting to dismiss the "Greater East Asia Co-Prosperity Sphere" as merely a piece of cynical propaganda, a feeble attempt to sway international public opinion into accepting Japanese hegemony in Asia. But to do so would be to overlook the powerful appeal of the idea to the hearts and minds of Japanese leaders, many of whom seemed to believe deeply in the in the benevolence of the ideal, even long after it had clearly failed to achieve realization.
To view the Co-Prosperity Sphere as entirely propaganda is also to overlook just how powerful an appeal the idea had throughout Asia as well. In point of fact, the Japanese were viewed as liberators by many of the peoples of Southeast Asia, who had long suffered under the yoke of Western colonial oppressors, and held high hopes that things would be better under the Japanese. It was only as mounting loses and increasing strain on resources forced Japan to abandon its plans to develop Southeast Asia and revert to exploitative resource extraction, and as the Japanese continued to insist on their own racial superiority, that the other Asians in the "Sphere" came to see the Japanese for what they really were - yet another racist and exploitative imperialist overlord with a hypocritical self-congratulatory ideology of colonial justification.
1. Peter Duus, "Japan's Wartime Empire: Problems and Issues," in Peter Duus, Ramon H. Myers, and Mark R. Peattie, eds., The Japanese Wartime Empire, 1931-1945 (Princeton, 1996), xxiii.