Korda, who turned in a 9-under 64 in the first round, was 1-over after five holes in the second round but had six birdies and no bogeys the rest of the way for a 36-hole total of 132.
Local favorite Feng Shanshan fired a bogey-free 64 to pull within two strokes of Korda. Stacy Lewis had a 66 and is tied with Feng for second.
Choi Na-yeon started the day tied with Korda for first but slipped to a 2-under 71 and is alone in fourth at 11-under for the tournament. World No. 1 Inbee Park, after a second-round 68, sits in fifth place at 9-under 137.
Four of the top five players in the tournament are in the women's golf Top 10. In addition to Park, Lewis is ranked third, Choi is No. 6 and Feng is ranked ninth. Korda is 26th.
Korda opened the second round with bogey at the first hole and, after a birdie at No. 4, had another bogey at the fifth. She got back on track with three consecutive birdies over Nos. 7-9. Three second-nine birdies left her two strokes clear of the field.
Feng scattered nine birdies across her scorecard, including three straight from the fifth through seventh holes. Lewis, also bogey-free, had six consecutive birdies over Nos. 12-17.