Yang shot up to the top of the leaderboard with a round of 65 and a two-round total of 10-under 134 at Sky 72 Golf Club’s Ocean Course. The 20-year-old took advantage of ideal weather conditions to tie the course record set by Tseng just a day prior.
Yang, who is playing on a sponsor’s invitation this week, had seven birdies and no bogeys.
“I felt good starting yesterday, but the difference today was that I was able to capitalize on my chances,” Yang said.
Tseng shot a 70, recovering from two bogeys on her first three holes to fire off four straight birdies and claim a share of second place with two-time defending champion Na Yeon Choi, who had another bogey-free round.
On the par-3 eighth hole, Tseng got into trouble again after pushing her tee shot to the right into an unplayable lie. After taking a penalty stroke, she got up and down for a bogey.
On the back nine, Tseng birdied holes 11 and 15 before dropping another stroke on the 16th.
“I’m very disappointed. I made a lot of mistakes today, especially with putting,” Tseng said. “If I can reduce the three-putts and not think too much I will do well tomorrow.”
Sunday’s final group will be a rematch of the 2009 final round. That year, Choi and Tseng were also paired in the same group, with Choi outdueling Tseng by one stroke to win the tournament with a birdie on the final hole.
Meanwhile, veteran Se Ri Pak was disqualified after the first round for inadvertently signing an incorrect scorecard. Pak signed for a 3 on the 17th hole instead of a 4.
“This was an honest mistake,” Pak said. “I am sure my fans are disappointed, but no one is more disappointed than I am.”
LPGA vice president of Tournament Business Affairs Mike Nichols said Pak came forward to acknowledge her mistake, and said her “honesty and integrity in bringing this to the attention of the rules officials should be applauded.”