Chaos theorists like to speculate how a butterfly flapping wings in Beijing might cause an earthquake in Latin America. But history could have something even more chaotic to say -- how a Japanese soldier's toilet stop near Beijing in 1937 plunged Japan into an eight-year war with China, rescued Europe from a decade of Nazi domination, and sent Japan to crashing defeat in 1945. The story is relevant, now that China has decided to mark the 60th anniversary of Japan's World War II defeat with a large commemorative exhibition at the Marco Polo bridge just outside Beijing.

The Chinese say some shooting by Japanese troops near the bridge on the night of July 7, 1937, followed by the false claim that a Japanese soldier was missing in a nearby town, were deliberate provocations by the Japanese military to justify Japan's subsequent attack into China.

But reliable Japanese sources who have interviewed in depth the Japanese participants in what is now called the Marco Polo Bridge incident tell a rather different story. They say there were some shots of unknown origin, probably accidental, fired during the exercises, and that a Japanese soldier sent to deliver an order was found to be missing soon after. Claiming he had to avenge the loss of the soldier, a belligerently Emperor-worshipping commander ordered preparations for a retaliatory attack on Chinese forces stationed nearby.