Park played a steady bogey-free round en route to a 7-under-par 65. She has a two-stroke edge over top-ranked and defending tournament champion Yani Tseng. Nicole Castrale, Danielle Kang, Park Hee-yong and Pornanong Phatlum are tied for third at 4-under 68.
Tseng was 2-under after nine holes but had a bogey at the par-4 10th. She immediately got that stroke back at the 11th, a par 3, and pulled close to Inbee Park with consecutive birdies over Nos. 13-15.
Inbee Park got going with a birdie at the par-3 second and moved up with three birdies over the span of Nos. 5-8. She had birdies at 12 and 13 and closed with a 4 at the par-5 18th hole.