SEOUL, Oct 20, 2012 (AFP) - He moved to joint three-under-par alongside fellow countryman Kim Dae-sub, who shot 70, leaving the pair three shots clear of Kang Wook-soon, who made 69 at the Woo Jeong Hills Country Club course.
Kang Kyung-nam, who led for the first two rounds, was a shot further back with a share of fourth place after slumping to a 77.
Kim Dae-hyun, runner up on OneAsia's Order of Merit in 2010 when he won the GS Caltex Maekyung Open, has made just two cuts on the circuit this year, although he won a matchplay event on the Korea Tour tour last month.
"This is a very difficult tournament this year, so any score under par is good," he said after a round that included seven birdies and two bogeys. "I am not sure if I could go five under par again."
Kim Dae-sub is hunting for a third Korea Open title -- but his first as a professional -- after winning as a 16-year-old amateur in 1998 and repeating the feat in 2001.
His performance is even more remarkable given he has not played tournament golf for nearly two years, having only just completed his compulsory military service.
"I am just trying to play steady and not expect too much," he said, despite winning last month on the Korean Tour, three weeks after being discharged after a 20-month service stint which allowed him time to play at weekends.
Kang, the only player to shoot the first two rounds under par, was six over on a day his putter went cold -- particularly on the ninth, when he four-putted for a triple bogey.
Star attraction Ryo Ishikawa from Japan is not out of the tournament after shooting a third-round 69 that leaves him six shots behind the leaders and alone in 11th place.
Y.E. Yang, the first player from Asia to win a Major and runner up in last week's Nanshan China Masters, shot a 72 to stand at two over for the tournament.
Standings after round three of the Kolon Korea Open:
210 - KIM Dae-hyun (KOR) 71-73-66, KIM Dae-sub (KOR) 72-68-70.
213 - KANG Wook-soon (KOR) 73-71-69.
214 - PARK Hyun-bin (KOR) 73-72-69, LEE Sang-hee (KOR) 77-68-69, CHOI Ho-sung (KOR) 71-71-72, KANG Kyung-nam (KOR) 68-69-77.
215 - NOH Seung-yul (KOR) 73-74-68, Y. E. YANG (KOR) 73-70-72, HONG Chang-kyu (USA) 71-71-73.
216 - Ryo ISHIKAWA (JPN) 75-72-69.