Saiki Fujita shot a 5-under 67 to take a two-stroke lead after the first round of the season-opening Daikin Orchid Ladies on Friday.
Fujita, who won her first major last September at the Japan LPGA Championship, had six birdies and one bogey at Ryukyu Golf Club.
Defending champion and 2010 money leader Ahn Sun Ju of South Korea was tied for second with Australian Nikki Campbell.
Fujita got off to a hot start on a chilly morning with birdies on the first and third holes.
The 25-year-old, four-time tour winner added three birdies in a four-hole stretch around the turn before offsetting her only bogey on No. 14 with a birdie from eight feet on No. 17.
"I didn't expect to play this well," Fujita said. "I usually don't have a good round when I birdie the first hole of the day. I'm happy with the way I played in windy conditions."