Popular tales of "Mrs. Watanabe" — the canny Japanese housewife who dabbles in currency trading in between school runs and shopping — barely begin to tell the story of the nation's retail traders in the foreign exchange market.
With almost 800,000 active forex accounts, Japan boasts the world's most powerful force of retail traders. It has doubled in size in little more than a decade and spurred some of the most dramatic price moves of recent times, including the January "flash crash" that hammered the dollar and sent the yen soaring.
Contrary to the widespread notion of "Mrs. Watanabe," most of the traders are middle-age men, who've been driven into the market by years of ultra-low interest rates. They toil in offices by day and trudge home to moonlight in foreign exchange, hoping to build a family nest egg in a country where banks pay savers next to nothing.