Grace Kim made a hole-in-one and joined Auston Kim in finishing with eight birdies for a nine-under 61 to share a five-way lead at the Dow Championship.
The highest score of the second round actually went to Denmark's Nicole Broch Estrup and Nana Korts Madsen, who birdied the final two holes to shoot a 10-under 60.
Americans Ally Ewing and Jennifer Kupcho shot 64, matching their opening-round foursomes, and shared the lead at 12 under par, along with the Thai tandem of Jaravee Boonchant and Chanettee Wannasaen and the duo of Ssu-chia Cheng and Wei-Ling Hsu.
England's Charlie Hull and Georgia Hall are three shots behind, with Lexi Thompson and Brooke Henderson two shots back at 10 under.
“I've had a lot of close shaves in the past, but this is my first time doing it, so I'm really excited,” said Grace Kim of her ace on the par-3 seventh hole.
“Apparently they were just trying to keep it close. All you see is it disappearing.”
Grace and Austin Kim birdied the next hole and then made five more shots on the back nine.
“I got a lot of good results from that hole because of Grace,” Auston said. “It was a really positive feeling moving forward from there.”
Watch Day 3 of the Dow Championship live on Sky Sports Golf from 11pm on Saturday.
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