World No.1 Ariya Jutanugarn shot the round of the day, a four-under 68, to surge to a four-stroke lead at the halfway point of the Blue Bay LPGA tournament in China.
Jutanugarn had birdies on the final two holes – and four of the closing seven on Thursday at the Jian Lake Blue Bay Golf Club – to take command over the rest of the field at seven-under.
Jennifer Song, Moriya Jutanugarn, and Gaby Lopez shot 71s and were in a tie for second at three-under.
First-round leader Thidapa Suwannapura carded a 75 and fell six strokes behind Jutanugarn, who was looking forward to potentially playing with her older sibling, Moriya, on Friday.
"I haven't played with her for so long," Ariya explained.
"We have so much fun. At the same time we didn't talk much when we played ... especially when there are three players in the group."
She said all the talk would distract the other player.
Local favourite Weiwei Zhang was the only other player to shoot under 70, thanks to a 69 in difficult conditions.
Australia's trio are out of contention, with Su Oh the best placed at two-over in a tie for 13th after rounds of 72 and 74.
Sarah-Jane Smith was four-over for the tournament, a stroke clear of Hannah Green.
The Blue Bay tournament is the last of five on the LPGA Tour's Asian swing.