VANCOUVER (Aug. 24, 2012) -- Lydia Ko, the 15-year-old top ranked amateur in the world, birdied four of her last seven holes for a second straight round of 68 to move her to 8-under par. A few moments later she was joined by South Korean Choi, who reeled off eight birdies over a 10 hole stretch in the middle of her round for a career-low 64.
"Today I didn't make any bogeys, and that was really helpful because sometimes a bogey in the middle of your round can make your confidence go a little down," said Ko, playing in just her third career LPGA event.
"My goal was 4-under today, and I shot [that] on the back nine which is good, so I think I really like the back nine, and hopefully it likes me too."
Ko came into the event having won the U.S Amateur title two weeks ago, becoming the second youngest player to do so.
Angela Stanford birdied the 17th for a round of 70 and a two day total of 5-under par. That left her tied with Inbee Park, who followed up her opening round 68 with a 71.
Suzann Pettersen, the 2009 champion, held a share of the lead at one point until a pair of bogeys on the back nine left her settling for a 69 and a 4-under total.
World number one Yani Tseng, who started the day as the leader, stumbled to a 75 which leaves her at 3-under par. Tseng failed to make a birdie, one day after carding eight of them.
The projected cut was sitting at 3-over par, which was good news for five of the 15 Canadians in the field.
Lorie Kane double bogeyed her sixth hole of the day which left her at 2-over through 11 holes.
Jessica Shepley had a pair of bogeys and a birdie through five holes to leave her at 2-over as well.
Samantha Richdale of Kelowna, B.C. was 2-under through six holes to leave her 3-over for the tournament along with Alena Sharp of Hamilton and Rebecca Lee-Bentham of Toronto who were through three and four holes respectively.