Chella Choi of South Korea shot a one-over-par 73 to hold on to a one-stroke lead midway through Saturday's second round of the weather-delayed LPGA Championship at Locust Hill outside Rochester, New York.
Choi, the overnight leader by one after an opening 67, reached six under par when she birdied her second hole of the day but went on to post three bogeys to reach the halfway mark of the tournament on four-under-par 140.
Tied for second place in the clubhouse on three-under 141 were 2012 British Women's Open champion Jiyai Shin of South Korea and Australian Sarah Jane Smith.
Shin also added a 73 to her opening 68, while Smith fired a 69.
Another stroke back was American Angela Stafford, who registered her second successive 71 for 142, with Japan's Chie Arimura another shot away at 143 after shooting a 72.
Defending champion Shanshan Feng of China bounced back from her first-round 74 with a 70 that put her at level par 144, a total she shared with American Michelle Wie, who posted an impressive 68 to gain ground after her opening 76.
Among the contenders playing in the afternoon wave was American Morgan Pressel, who had been tied for second with Shin after Friday's first round.
With Thursday's scheduled opening round scrubbed because of lightning and torrential rain, organizers were hoping to get in 36 holes on Sunday to finish the second major championship of the LPGA season.