SEOUL, May 11, 2013 (AFP) - Ryu, 12 under after three rounds, got lucky when overnight leader Kim Hyung-sung (71) bogeyed the last to slip down to second place at the Namseoul Country Club on the outskirts of the Korean capital.
Four players share third place at nine under -- Kang Kyung-nam (68), Lee Kyoung-hoon (69), Kim Do-hoon (70) and reigning Kolon Korea Open champion Kim Dae-sub (71).
Defending champion Kim Bi-o is three under in 20th place after shooting a 70.
Although he had six birdies and just one bogey on Saturday, Ryu said the golf was tougher than his scorecard suggested.
"The greens were much faster today and some of the pin positions were very tricky," the 31-year-old said in a OneAsia press release. "I wasn't always in good position with my tee shots, but fortunately my short game was okay and I managed to make birdies."
Second-placed Kim also scrambled his way around the course and was lucky to get away with a bogey on the last after seemingly hooking his tee shot into thick forest.
He played a provisional, but on his way up spotted his original ball had actually ricocheted into the rough on the edge of the fairway.
"The last hole was not good," he said. "I shouldn't let something like that happen at this stage of the tournament."
Leader Ryu, a Japan Tour regular whose first professional win came only at their Coca-Cola Tokai Classic last year, is desperate for a second title so his son can live up to a weighty name conferred on him by his parents.
Ryu's three-year-old is named Da-seung which means "multi-winner".
"I'll just try to play the par three holes level tomorrow and see if I can make a few birdies on the par fives," said Ryu. "We'll see what happens."
Scores after round three:
204 - Ryu Hyun-woo (KOR) 72-65-67.
205 - Kim Hyung-sung (KOR) 67-67-71.
207 - Kang Kyung-nam (KOR) 68-71-68, Lee Kyoung-hoon (KOR) 67-71-69, Kim Do-hoon-753 (KOR) 67-70-70, Kim Dae-sub (KOR) 70-66-71.
209 - Lee Tae-hee (KOR) 69-72-68.
210 - Byun Jin-jae (KOR) 71-68-71, Kim Hui-soo (KOR) 70-69-71.