Danielle Kang and Charley Hull were two shots back on a chilly, windy, damp day at the Sky 72 Ocean Course.
Sung Hyun Park, the U.S. LPGA Tour's top-ranked player, was among a handful of players three shots back.
Park could have been closer but took a double-bogey 5 on the par-3 17th.
Hataoka was matter-of-fact about the tough conditions.
"As a professional golfer, I believe that we need to be able to play solid and under any condition, including very strong winds," she said.
She had eight birdies through 16 holes to reach 8 under, but then dropped a shot at 17.
The 19-year-old Hataoka was ranked in triple digits just a year ago but has climbed to No. 14 in the LPGA rankings - the top Japanese.
She won her first LPGA title in June at the NW Arkansas Championship in her second season on the tour, and is aiming to represent Japan in the Tokyo Olympics.
"This season, a lot of different elements are coming together for me so that I can play a stronger game," she explained. "For instance, my shots are more solid and my putting has improved greatly."
Kang said she also tried to make the most of the blustery conditions.
"I actually really like tough conditions," Kang said. "I'm ready to play, and whatever happens, happens. I actually like the wind."
Michelle Wie turned 29 on Thursday but failed to celebrate - she had a poor 76.
The KEB Hana Bank tournament is the first in five weeks of play across South Korea, Japan, Taiwan, and China.
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