The Start of WW2?

[bearoutwest]

http://forum.12oclockhigh.net/showthread.php?t=36255

This topic – in the Japanese and Allied Air Forces in the Far East section of the forum – titled “First American citizens killed in WW2” got me thinking.

Whereas I understand the point of the original question, which was to investigate the civilian aircraft shot down over Pearl Harbor on 7-December, I did ask the question of whether the USN sailors killed during the “unintentional” Japanese dive bombing attack on the USS Panay on the Yangtze River in 1937 also qualified as the first American citizens killed in WW2. I was recently reminded, that Robert Short – an American pilot demonstrating a Boeing fighter in Shanghai 1932, and subsequently short down and killed while intercepting a Japanese raid on the city, predated the USS Panay sailors.

So, in terms of a continuous timeline….what reasonably constitutes the start of WW2 hostilities?
- 1931 Manchuria?
- 1932 Shanghai?
- 1936 Spain? – perhaps not, as the end of conflict in Spain in 1939 did not continue into the greater world conflict.
- 1937 China?
- 1939 Poland?

Any thoughts?

Regards,
...geoff