* 1939 – 1945, the Second Battle of the Atlantic.

Subsequent formalizations were framed as attempts to define " effective calculability " or " effective method "; those formalizations included the Gödel – Herbrand – Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's " Formulation 1 " of 1936, and Alan Turing's Turing machines of 1936 – 7 and 1939.

* 1890 – Anthony Fokker, Dutch aviation engineer ( d. 1939 )

* 1939 – André Ouellet, French-Canadian politician

* 1852 – Ferdinand von Lindemann, German mathematician ( d. 1939 )

* 1939 – Alan Ayckbourn, English writer

* 1939 – Johnny Raper, Australian rugby league footballer

* 1939 – The 1939-40 New York World's Fair opens.

* 1939 – NBC inaugurates its regularly scheduled television service in New York City, broadcasting President Franklin D. Roosevelt's N. Y. World's Fair opening day ceremonial address.

* 1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.

* 1939 – William Least Heat-Moon, American author

* 1939 – Edward Patten, American singer-songwriter and producer ( Gladys Knight & the Pips ) ( d. 2005 )

* 1939 – Bulle Ogier, French actress

* 1939 – Romano Prodi, Italian politician and statesman

* 1939 – Hércules Brito Ruas, Brazilian footballer

* 1939 – Albert Einstein and Leó Szilárd write a letter to Franklin D. Roosevelt, urging him to begin the Manhattan Project to develop a nuclear weapon.

* 1939 – Benjamin Barber, American theorist

* 1939 – Wes Craven, American director

* 1939 – John W. Snow, American politician, 73rd United States Secretary of the Treasury

* 1984 – Marvin Gaye, American singer ( The Moonglows ) ( b. 1939 )

* 2001 – Trinh Cong Son, Vietnamese composer ( b. 1939 )

Eastern European theorists include Pyotr Stolypin ( 1862 – 1911 ) and Alexander Chayanov ( 1888 – 1939 ) in Russia ; Adolph Wagner ( 1835 – 1917 ), and Karl Oldenberg in Germany, and Bolesław Limanowski ( 1835 – 1935 ) in Poland.

During the Sino-Japanese War ( 1937 – 1945 ) and World War II ( 1939 – 1945 ), the Special Research Units of the Imperial Japanese Army, such as Unit 731, conducted human experimentation on thousands of Chinese, among others.

By 1939 Nissan's operations had moved to Manchuria, then under Japanese occupation, where its founder and President, Yoshisuke Ayukawa, established the Manchurian Motor Company to manufacture military trucks.

* 1939 – Jun Henmi, Japanese writer and poet

* 1939 – Sonosuke Fujimaki, Japanese fencer

The 400 Million ( 1939 ) depicted the history of modern China and the resistance to the Japanese invasion, including dramatic shots of the Battle of Taierzhuang.

Moreover, the pact erased the legal distinction between war and peace since the signatories, having renounced the use of war began to wage wars without declaring them as evidenced by the U. S. intervention in Central America, the Japanese invasion of Manchuria in 1931, the Italian invasion of Abyssinia in 1935, the Soviet invasion of Finland in 1939, and the German and Soviet Union invasions of Poland.

During the Japanese occupation of Hainan ( 1939 – 1945 ), the Li suffered heavily.

* 1939 – A Japanese Imperial Army ammunition dump explodes at Hirakata, Osaka, Japan, killing 94.

* 1939 – Sumio Iijima, Japanese physicist

The Battle of Khalkhin Gol, a border conflict of 1939 ostensibly between Mongolia and Manchukuo, saw heavy fighting between Japanese and Soviet forces.

In the census of December 1939, the total population of the South Pacific Mandate was 129, 104, of which 77, 257 were Japanese ( including ethnic Taiwanese and Koreans ).

Thus at the Battle of Lake Khasan, in 1938, and the Battle of Khalkhin Gol, in 1939, major border clashes with the Imperial Japanese Army, the doctrine was not used.

In September 1939, Menzies found himself a wartime leader of a small nation of 7 million people that depended on Britain for defence against the looming threat of the Japanese Empire, with 100 million people, a very powerful military, and an aggressive foreign policy that looked south.

The history textbook controversy centers upon the secondary school history textbook Atarashii Rekishi Kyōkasho (" New History Textbook ") said to minimise the nature of Japanese militarism in the First Sino-Japanese War ( 1894 – 95 ), in annexing Korea in 1910, in the Second Sino-Japanese War ( 1937 – 45 ), and in the Second World War ( 1939 – 45 ).

* 2011 – Jun Henmi, Japanese author and poet ( b. 1939 )

British historian Antony Beevor views the beginning of the Second World War as the Japanese invasion of Manchuria in August 1939.

Soviet troops fought the Japanese during the Battle of Khalkhin Gol in Mongolia, 1939.

Although the battle was a Soviet victory, the Japanese dismissed it as an inconclusive draw, and on 11 May 1939 decided to move the Japanese-Mongolian border up to the Khalkhin Gol River by force.

< imagemap > File: 1940s decade montage. png | Above title bar: events during World War II ( 1939 – 1945 ): From left to right: Troops in an LCVP landing craft approaching " Omaha " Beach on " D-Day "; Adolf Hitler visits Paris, soon after the Battle of France ; The Holocaust occurred during the war as Nazi Germany carried out a programme of systematic state-sponsored genocide, during which approximately six million European Jews were killed ; The Japanese attack on the American naval base of Pearl Harbor launches the United States into the war ; An Observer Corps spotter scans the skies of London during the Battle of Britain ; The atomic bombings of Hiroshima and Nagasaki are the first uses of nuclear weapons, killing over a quarter million people and leading to the Japanese surrender ; Japanese Foreign Minister Mamoru Shigemitsu signs the Instrument of Surrender on behalf of the Japanese Government, on board USS Missouri, effectively ending the war.

* June 14 – Tientsin Incident: The Japanese blockade the British concession in Tianjin, China, beginning a crisis which almost causes an Anglo-Japanese war in the summer of 1939.

** Kanoko Okamoto, Japanese novelist, poet, and Buddhism scholar ( d. 1939 )