Shadows of Empire: Unveiling Japan's Quest for the Greater East Asia Co-Prosperity Sphere

by Ashton Hinsdale

​On August 1st, 1940, Japanese Foreign Minister Matsuoka Yosuke officially delivered a decree that codified the unofficial policy and sentiments of the Japanese administration and military. This marked the establishment of the Greater East Asia Co-Prosperity Sphere (GEACPS), a strategic initiative aimed at creating a bloc of East Asian nations led by Japan and free from Western colonial powers.[1] With the use of an aggressive ideological framework, Asia must unite in the Japanese "spirit" and via Japanese stewardship.[2] Advocating for Pan-Asian unity under Japanese dominion, the GEACPS signified Japan's ambitions to expand its influence over territories not only under its control, such as Manchuria, Taiwan, Korea, and the Marshall Islands, but also those in Southeast Asia under Western colonial rule.

The proposed economic federation and sphere of security included new territories already occupied by European foreign powers in British Malay, the Dutch East Indies and French Indochina, and British Burma.[3] It's abundantly clear that the goal of the Japanese foreign policy, and later the security policy, was to galvanize the economic potential of these regions for Japanese industry. Japanese industry had come to rely on critical resources provided by Western powers via trade, chiefly iron, tin, rubber, and, most importantly, petroleum (Ibid. 228). Japan's aggressive expansion was partly fueled by the need for natural resources like iron, tin, rubber, and especially petroleum, the supply of which was severely impacted by the Roosevelt administration's embargoes.


The formal declaration of policy under the GEACPS was just a diplomatic formality for Japanese economic interests in Southeast Asia. This later manifested into a brutal military and naval campaign into South East Asia under the guise of Pan-Asian ideology and rhetoric. Using the Taiwan as an important launching pad for personnel, intelligence, and intercultural exchanges, Japanese military branches conducted lightning fast amphibious assaults and well-coordinated ground troops in what is known as the Southern Expansion Campaign.

• 1931-1932: Japan invaded Manchuria, marking the beginning of aggressive territorial expansion in Asia.
• July 1937: The Second Sino-Japanese War began, with Japan launching a full-scale invasion of China.
• August 1940: The Greater East Asia Co-Prosperity Sphere was announced.
• September 1940: Japan signed the Tripartite Pact with Germany and Italy, aligning itself with the Axis powers.
• September 22, 1940: Japanese troops occupied northern French Indochina (present-day Vietnam, Laos, Cambodia) after the Vichy French government granted them access.
• July 1941: Japan occupied southern French Indochina, further expanding its control in Southeast Asia.
• December 7/8, 1941: Japan attacked Pearl Harbor, Hong Kong, Malaya, Singapore, and the Philippines, marking a significant escalation in the Pacific War.
• December 1941 - January 1942: Japanese forces rapidly advanced into British Malaya and captured the key British fortress of Singapore in February 1942.
• January 1942: Japan invaded Burma (Myanmar), aiming to cut off Allied supply lines to China and secure a buffer zone against possible British counter-attacks from India.
• February-March 1942: Japan conquered the Dutch East Indies (now Indonesia), securing vital oil resources.
• March 1942: Japanese forces occupied the Solomon Islands and the northern coast of New Guinea, extending their defensive perimeter in the Pacific.
• May 1942: Japan suffered a strategic defeat at the Battle of Coral Sea, the first major naval engagement in which aircraft carriers played a decisive role.
• June 1942: The turning point came with Japan's defeat at the Battle of Midway, where the U.S. Navy decisively defeated the Japanese fleet, significantly weakening Japan's naval power.
• 1942-1944: Japan continued to expand in Southeast Asia and the Pacific but faced increasing resistance and counter-attacks by Allied forces.
• 1944-1945: The Allied "island-hopping" campaign bypassed many Japanese strongholds in the Pacific, recapturing territory and moving closer to Japan.
• August 1945: After the atomic bombings of Hiroshima and Nagasaki and the Soviet declaration of war on Japan, Japan surrendered, ending World War II in Asia and the Pacific.

Once perceived as Asian liberators or models of modernization, began replacing the functions set by their colonial predecessors in extractive industries. The "colonial yoke" remained in place. In some cases, nationalist movements and anti-colonial sentiments made certain Asian populations initially receptive to the Japanese occupation as an Asian contemporary that would respect their fellow Asian people's culture, religion, and society from Western colonialism.[4] In Vietnam and the Philippines, there was an underlying perception of the Japanese invasion as an opportunity for liberation, which likely contributed to national post-colonial consciousness.[5] Over time, the Japanese intentions became apparent and fixated on the extractive industries needed to fund their war efforts. The result was the massive destruction of property, land, and human life, which contributed to further colonial subjectivity. When Japanese troops aligned themselves with the Vichy French government in Indochina in 1941, much of the old colonial systems remained intact, and Vietnam later experienced one of the worst famines in its history as Japanese troops burned much-needed rice as fuel without much recourse. In Indochina, Malaysia, Thailand and Burma as many as 300,000 rōmusha laborers perished to construct the Burma Siam railroad, suffering from disease and fatigue. Poor Japanese women, or sometimes colonial Taiwanese and Korean women, were shipped to these parts of the Japanese realm to serve as comfort women to soldiers and laborers during these periods.[6]


After these subsequent atrocities, national movements began to question the official rhetoric of the Japanese administration in Southeast Asia, vastly contributing to their respective national movements and consciousness. For many of these nations, their service to the house of three masters came to an end in 1945 after the defeat of the Japanese and a vastly different world order came about.

1. International Journal of Humanities and Cultural Studies (IJHCS), Volume 6, Issue 1, Article "Japan’s Ideologies of Expansion: The Southern Expansion Campaign" https://www.arcjournals.org/pdfs/ijhcs/v6-i1/1.pdf
​2. Takeda, “Translation of The Greater East Asia Co-Prosperity Sphere by Koji Takeda”; Office of War Information, Bureau of Oversas Intelligence, “Japanese Treatment of Moslems in Java and Malaya, and Influence in Near East.”
3. Beasley, Japanese Imperialism 1894 - 1945, 227.
​4. My-Van, “Japan through Vietnamese Eyes (1905–1945),” 139.
5. My-Van, 129, 139; Abinales and Amoroso, State and Society in the Philippines, 160.
6. Dower, War without Mercy, chap. 3.