Earn double miles on all JAL Group domestic and international flights from December 1, 2005 through March 31, 2006.

Eligible Flights: All JAL Group domestic and international flights including JAL codeshare flights
Eligible Fares: Any fare eligible for JMB mileage accumulation

To earn double miles, register campaign code [52D] before your flight. Double mile offer cannot be combined with other flight mile bonus offers.

http://www.japanair.com/e/promotions/wmiles05.php