Tokyo, Japan · June 30, 1941

On September 19, 1931, soldiers of the Kwantung Army (even­tually the largest, most pres­ti­gious branch of the Impe­rial Japa­nese Army) invaded Man­chu­ria in North­east China from their base at Port Arthur (present-day Dalian or Lüshun Port) and estab­lished a pup­pet state they called Man­chu­kuo. This event was a mas­sive act of insub­ordi­nation against the express orders of the poli­tical and mili­tary leaders in Tokyo. Suddenly thrown into dis­array, the leaders were power­less to stop the erup­tion of locally based Japa­nese aggres­sion in Northeastern China. None­the­less, Tokyo dis­patched rein­force­ments to Man­chu­kuo from Japan and Japa­nese-held Korea and ini­tiated large-scale “anti-bandit opera­tions” to quell a growing resis­tance move­ment in the country’s newest possession.

For the rest of the 1930s Japa­nese mili­tary and civil­ian offi­cials were of two minds: expand their im­perial holdings west and north from their Man­chu­kuo base by attacking Inner Mon­go­lia (1933–1936 skir­mishes), the Soviet Union (Siberia), or the Soviets’ proxy state, Outer Mon­go­lia (present-day Mon­go­lia) (1938–1939, deci­sive Soviet vic­tories). Either that or expand south by attacking equally tempting West­ern colo­nial holdings in British Malaya and Singa­pore, the Dutch East Indies (present-day Indo­ne­sia), and the Ameri­can Philippines (see map).

In July 1940 the Japa­nese govern­ment formally decided on a twin policy at least to the south of Man­chu­kuo: first, win the existing war (since 1937) on China’s main­land by inter­dicting the life­lines that brought West­ern arms, muni­tions, and related mate­riel to their Chin­ese enemy; and, secondly, gain access to the desired raw mate­rials from Malaya and the East Indies, if neces­sary by starting a new war in Southeast Asia. Toward the end of Septem­ber 1940, Japan took the first step in imple­menting this plan and moved troops into the north­ern part of French Indo­china (present-day Viet­nam) by agree­ment with the Ger­man vassal state of Vichy France.

On this date in 1941 Japa­nese offi­cials shelved any plans for expan­sion north­ward or west­ward from their Man­chu­kuo base. Two days later, July 2, 1941, the Liai­son Con­fer­ence, con­sisting of senior Japa­nese govern­ment offi­cials and Army and Navy gene­ral staffs, formally con­firmed the deci­sion to expand south­ward. This was the moment when war between Japan and the Western powers became inevitable.

Japanese and Western Holdings in the Asia Pacific Region, September 1939

Map of imperial holdings in Asia Pacific, September 1939

Above: A map of imperial possessions in the Asia Paci­fic region as of Septe­mber 1939. The start of the Second Sino-Japa­nese War (1937–1945) was the inau­gu­ral event in World War II and argu­ably the dead­liest, cost­liest global con­flict ever. The total num­ber of Chinese mili­tary and non­mili­tary dead was upwards of 20 mil­lion, with maybe 15 mil­lion wounded. Addi­tion­ally, Japa­nese “kill all, loot all, burn all” opera­tions created 95 mil­lion Chi­nese refu­gees. Chi­nese forces claim to have killed at most 1.77 mil­lion Japa­nese sol­diers during the eight-year war. The Paci­fic islands en­circled in red lines (the Northern Marianas, Carolines, Marshall Islands, and Palau groups) are former Ger­man posses­sions under Japa­nese adminis­tra­tion following World War I. They would play a major role in facili­tating Japa­nese vic­tories over the Allies in the early years of the Pacific War.

“Manchukuo: The Newborn Empire,” Japanese Propaganda Film, Circa 1937