KUALA LUMPUR, 10 Oct, 2014 (AFP) - The South Korean added two more birdies on the back nine before suffering the only blemish on her card at the Kuala Lumpur Golf and Country Club, a bogey on the par-four 14th hole, leaving her at 11-under for the event.
Hot on her heels were a hard-charging trio tied at 9-under, led by Japan's Ayako Uehara, who orchestrated a bogey-free 63.
England's Jodi Ewart Shadoff and 17-year-old phenomenon Lydia Ko of New Zealand stayed level with Uehara after both shot 64.
South Korea's Eun-Hee Ji joined them 9-under, while three golfers -- Shanshan Feng of China, Azahara Munoz of Spain, and Thailand's Pornanong Phatlum -- were a further stroke back.
World number one Stacy Lewis, who held the first-round lead, surrendered it after the American posted an uncharacteristic four bogeys on the front nine on the way to an even-par 71, leaving her five strokes off the lead.
Last year's winner Lexi Thompson of the United States saw her hopes of a repeat suffer a blow as she struggled Friday to a 73, putting her at two-over for the tournament, well off the pace.
The $2 million tournament is part of a multi-event swing through Asia by the US LPGA.
Scores in brief:
131 - So Yeon Ryu (KOR) 66-65
133 - Ayako Uehara (JPN) 70-63, Jodi Ewart Shadoff (ENG) 69-64, Lydia Ko (NZL) 69-64, Eun-Hee Ji (KOR) 66-67
134 - Shanshan Feng (CHN) 67-67, Pornanong Phatlum (THA) 67-67, Azahara Munoz (ESP) 69-65
135 - Chella Choi (KOR) 69-66, Jenny Shin (KOR) 67-68