Korea's Chung Joon opened up a three-stroke lead going into the final round of the US$400,000 Maekyung Open with a rollercoaster four-under-par 68 on Saturday.
Chung, chasing his first victory on the Asian PGA Tour, has a three-round total of 10-under-par 206 (70-68-68) and leads fellow-Korean Choi Yoon-soo and Amandeep Johl of India, who carded scores of 68 and 69 respectively.
Veteran Choi Gwang-soo, whose victory in the Maekyung Open in 2001 made him the oldest winner on the Asian PGA Tour at 41 years and two months, moved into a challenging position with a sizzling 66 at Nam Seoul Country Club.
Choi, whose two Tour wins have come in Korea, is alone in fourth spot, four shots adrift of leader Chung. Thailand's Thongchai Jaidee, Asia's number one in 2001, is a further stroke behind in joint fifth spot with Shin Yong-jin after a 69.
The 31-year-old Chung, who traditionally plays well on home soil, had good opening and closing spells to a round which dipped alarmingly midway through.
He started with a birdie, eagled the par-five fourth hole and birdied the fifth hole to put himself in a commanding position. But bogeys at the seventh, 10th and 13th holes threatened to derail his round before he finished strongly with three birdies in the last five holes.
Johl struggled early on with two bogeys in the first three holes but an eagle at the 16th helped him to a 69 and kept him in the chase for a maiden title on the Asian PGA Tour.
Defending champion Eddie Lee of New Zealand, who won as an amateur last year,is eight strokes off the pace after a third round 69.
Leading third round scores:
206 - Chung Joon (KOR) 70-68-68
209 - Choi Yoon-soo (KOR) 71-70-68, Amandeep Johl (IND) 70-70-69
210 - Choi Gwang-soo (KOR) 71-73-66
211 - Shin Yong-jin (KOR) 74-71-66, Thongchai Jaidee (THA) 74-68-69
212 - Richard Backwell (AUS) 69-73-70, Ted Oh (KOR) 71-70-71, Moon Sung-wook (KOR) 71-71-70, Kim Hyung-tae (KOR) 71-71-70, Kim Kyung-tae [A] (KOR) 74-68-70
213 - Chung Jae-hoon (KOR) 70-72-71, Mo Joong-kyung (KOR) 71-71-71 Suk Jong-ryul (KOR) 69-71-73
214 - Eddie Lee (NZL) 72-73-69, Choi Sang-ho (KOR) 73-72-69, Lee In-woo (KOR) 70-74-70, Sushi Ishigaki (JPN) 73-69-72
215 - Thaworn Wiratchant (THA) 73-75-67, Kim Bong-Jin [A] (KOR) 73-71-71, Yang Yong-Eun (KOR) 74-70-71, Lim Hyung-Soo (KOR) 73-71-71