Axis Pact member Japan and the USSR conclude a nonagression pact in April, 1941.
Japan acts as a mediator in Thailand’s Indochinese dispute and, in 1941, Battambong, Siemrap, Champasak and Lanchang are returned to Thai conrol.
Vienamese nationalist resistance leader Ho Chi Minh organizes the Leaague for the independence of Vietnam, or Viet Minh, along Communist ideological lines in 1941.
In an imperial conferece held in Tokyo on September 6, 1941, war minister general Tojo Hideki expresses his widely-supported belief that the US is already visiting economic war upon Japan; that all-out-war must inevitably follow, and that Japan is best served by taking quickly the military initiative.
The minority view, favoring a continuation of negotiations with Washington and espoused by Emperor Hirohito and prime Minister Konoe, is given a six-week window to achieve a set of minimum demands including an immediate halt to economic sanctions, a free hand for Japan in China and rights for Japan in Indochina.
Konoe, making no progress with Washington, resigns on October 16 and is replaced by Tojo.
Negotiations between US secretary of state Cordell Hull and emmissaries of Tojo’s cabinet continue to stall.
US authorities, having secretly cracked Japan’s diplomatic code, know that a rejection of Japan’s minimum demands will result in war.
On November 26, 1941, Hull’s formal reiteration of the US position demands Japanese withdrawal from Indochina and China, recognition of the Jiang Jeishei regime in China, renunciation of territorial expansion, and acceptance of the Open Door policy of equal commercial access to Asian markets.
Tojo orders a large and well-equipped Japanese task force to depart the Kuril Islands in late November and head into the Pacific.
The Japanese hold on imperial conference on December 1 to discuss their option and decide to implemant plans for a crushing aerial attack against the US Pacific Fleet stationed at Pearl Harbor in the Hawaiian Islands.
On December 2, the Japanese task force recieves a coded order to begin the air attack.
Arriving undetected off the Hawaiian Islands on the morning of December 7, 1941, the Japanese task force launches two successive waves of more than 350 bombers, torpedo planes and fighters, sinking or disabling 18 ships and destroying about 200 aircraft, most on the ground.
While the attack cripples US naval power in the Pacific, it misses the American aircraft carriers altogether, as they are all out on missions elesewhere.
This serendipity aside, the US Navy and Marine Corps lose 2,117 men and the Army, 218; 68 civilians also die.
More than 1,200 suffer wounds from the attack.
Japan loses 29 planes.
The Japanese attack brings the formerly isolationist United States into the war on the side of the Allies.
Japanese air and naval forces launch nearly simultaneous attacks on British Malaya, Burma, the Dutch East Indies, the Philippines, Singapore, Thailand, Guam, and Wake Island.
British vice-admiral Tom Phillips, immediately upon hearing of the Japanese landings in Malaya, puts to sea from his base in Singapore with the new battleship Prince of Wales and the battle cruiser Repulse, accompanied by an escort force but no air cover.
Japanese planes spot the small task force on December 9, 1941 about 50 miles (80 kilometers) from the Malayan coast and 150 miles (240 kilometers) from Singapore.
The British warships are sunk the following day.
Japanese forces land at Luzon in the Phillipines on December 10, 1941.
US General Douglas MacArthur’s 55,000 Filipinos and Americans attempts to hold the island are overwhelmed by the large ground assault beginning December 22 and supported by waves of Japanese air strikes at Manila on December 27 and 28.
Japan’s army in Thailand enters southern Burma in December 1941 and takes Victoria Point, driving the undermanned British garrison back into Rangoon.
On December 19, 1941, US General Claire L. Chennault and his band of volunteer pilots, known collectively as the Flying Tigers, establishes a headquarters 150 miles (240 kilometers) from Rangoon to assist in the Burmese effort.
The Japanese capture the undefended British Crown Colony of Hong Kong on December 25, 1941.
The Japanese forces in the Philippines take Manila and the naval base of Cavite on January 2.
MacArtuur orders a retreat to the Battan Peninsula.
