Shin, seeking her fifth LPGA victory, stands at 16-under 200. Second-pace Morgan Pressel trailed by only one stroke when she finished her second round of 66 in the morning, but a third-round 70 had her at 12-under 204.
Shin is the reigning Women's British Open champion and is already a four-time winner on the LPGA Tour, although she is considered a rookie this season.
Last year, the 21-year-old Korean became the first non-LPGA Tour member in history to win three events in one season. She earned victory No. 4 at this season's HSBC Champions in Singapore.