The European Ryder Cup star birdied two of the final three holes to finish three rounds at 18-under 198 on the Taiheiyo Club course.
Japan's Nozomi Kawahara was second after a 66.
England's Lee Westwood, the tournament winner in 1996, 1997 and 1998, shot a 67 to join Taiwan's Yeh Wei-tze (69) at 12 under.
Copyright 2004 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.