Unheralded Miki Sakai shot a 6-under-par 66 to take the lead after the first round of the Japan LPGA Championship on Thursday.
The 22-year-old Sakai, who finished a career-best third at the Vantelin Ladies Open in April, reeled off seven birdies, including three in a row from the sixth hole at Eniwa Country Club.
She spoiled what would have been a perfect round with her only bogey of the day on the 18th, but still holed out two shots clear.
Yumiko Yoshida, who bagged her third title of the season at last week's Golf 5 Ladies, shared second place with Yuki Ichinose and South Korea's Lee Bo-mee.
Mamiko Higa was another shot off the pace in a six-way tie for fifth place.
