Ariya Jutanugarn and In-Kyung Kim each birdied their final hole Thursday to share the lead during the suspended second round of the LPGA Lotte Championship.
The South Korean player carded a seven-under round of 65 on the third day of the tournament to move to 17 under overall for the tournament at the Ko Olina Golf Club.
A 71-minute rain delay meant a second straight day with weather interruption and it also lead to the second round not being completed.
Canada's Alena Sharp (66) and Cristie Kerr (62) of the United States are tied for second at 14-under 202 in the tournament which has featured weather delays in each of the first three rounds.
Kerr shot 29 on the back nine, making a birdie on every hole with the exception of pars at holes No. 10 and 14. Ryu can overtake New Zealand's Lydia Ko for the No. 1 ranking in the world if she wins the event and Ko finishes fifth or worse.
Stacy Lewis (68), first-round co-leader Mi Hyang Lee (70), Alena Sharp (69) and Becky Morgan, who also has two holes remaining, share fourth place at eight-under.
Minjee Lee, the defending champion, fired a 4-under-par 68 on Friday and sits T15. Jang doesn't have a bogey in her first 34 holes of the tournament.
"Overall, my shots didn't feel particularly solid, but my putts fell really well and gave me a number of birdies", Jang said. She was just one back after sinking a 15-footer from the fringe on the 16th. "I was just kind of on autopilot", said Sharp.
She feels comfortable in Ko Olina on the island of Oahu, having shot a brilliant 64 in the final round to win previous year. I love traveling to all the different places we play and the fantastic courses we play.
Lee, 20, is defending the Lotte Championship that she won a year ago in Hawaii.
The cut will be determined after the completion of the round Friday morning.
Englishman James Heath's 4-over 77 was unremarkable except for his experience on No. 17, where the former Augusta State golfer made a decision to remove his pants, shoes, and socks to play a chip out of shallow water in shirt, cap, and underwear.