Defending champion Amy Yang carded a 3-under 69 to lead by one halfway through the LPGA Thailand on Friday.
Yang trailed first-round leader Lexi Thompson by two before teeing off at Siam Country Club, then had consecutive bogeys on Nos. 5 and 6, but rallied with four birdies, including on the par-3 12th.
At 9 under overall, the South Korean was one shot ahead of countrywoman Q Baek (71) and Americans Jessica Korda (66) and Thompson (72).
"I struggled a little bit on the front, two bogeys straight, but I stayed patient, got through it well," Yang said. "Leading by one shot is not much, and two more rounds is still a lot of golf."
Korda's low round of the day, matched by Haru Nomura of Japan, was capped by a 12-foot eagle putt on her last hole.
Xi Yu Lin of China hit a hole in one on the 186-yard, par-3 16th, and earned a Honda Accord.