Haeji Kang shot a 5-under 67 on Thursday to take a two-stroke lead over five players, including three fellow South Koreans, after the first round of the LPGA's KEB-Hanabank Championship.
Lee Il-hee and defending champion Amy Yang shot 69s along with another South Korean, Mirim Lee. Australian Minjee Lee and Catriona Matthew of Scotland were also tied for second on the Ocean Course at the Sky72 Golf Club.
There was a large group tied for seventh with 70s, including Suzann Pettersen of Norway and American Brittany Lincicome.
Second-ranked Inbee Park, who could move to No. 1 with a win in the absence of top-ranked Stacy Lewis of the United States, was a further shot back with a 71. Park married swing coach Gi Hyeob-nam on Monday in Seoul.