South Korean veteran Jang Ik-jae shot a 4-under 67 to open a one-stroke lead after the first round play at the Kolon Korea Open golf tournament here on Thursday.

The 40-year-old enjoyed a bogey-free round that included an eagle on the par-4 10th hole, along with two birdies at the par-71 Woo Jeong Hills Country Club in Cheonan, 90 kilometers south of Seoul in South Chungcheong Province.

"I didn't hit too well off the tee," said Jang, a Japan Golf Tour member seeking his first win on native soil since 2005. "But I hit some good recovery shots and putted well."

The 1 billion won (US$940,000) tournament, co-sanctioned by the Korean Tour and OneAsia Tour, is the oldest men's golf competition in South Korea.

Four golfers are sitting one stroke behind Jang, including Kang Sung-hoon, who won the CJ Invitational on the domestic tour last week.

Kang's up-and-down round featured five birdies and an eagle, which were negated by four bogeys.

"We had some difficult pin placements," Kang said. "I was too inconsistent today. I will try to reduce mistakes tomorrow." 

Former world No. 1 Rory McIlroy opened his third Korea Open with a 1-under 70, tied in 12th place with six others.

He traded a bogey with a birdie on the front nine. He then committed a double bogey on the par-3 13th when he found water off the tee, but recovered with three birdies over his last five holes.

McIlroy, currently ranked No. 6, finished tied for third in 2009 and was the runner-up in 2011. 

This is McIlroy's first tournament after four weeks off, and he said after the round that he had to shake off some rust to finish the round under par.

 "I just wasn't very comfortable with the tee shot," he was quoted as saying on OneAsia Tour's website. "I took a long time to get settled over it and then just didn't make a very good swing."

 The 24-year-old, still seeking his first win of 2013, also noted difficult pin placements.

 "It was tough, some of the pin positions out there today were brutal, just cut on slopes and very hard to get close to them," he said. "And when you did get close to them, you left yourself very tricky putts. 

 Defending champion Kim Dae-sub opened his title defense with a 2-under 69, after picking up four birdies against a double bogey. 

 Kim has won the Korea Open three times, twice as an amateur. He started his round on the back nine and three-putted for a double bogey on the par-4 11th, but went on to score four birdies without a bogey the rest of the way.

 "I haven't been playing well of late, but I gained some confidence after one round here," Kim said. "If I can stay composed like today, I think I can play well the rest of the tournament."

 Only 18 players finished the round under par on the 7,208-yard layout. South Koreans dominated the leaderboard, and Eric Mina, OneAsia Tour's rookie from the United States, was the top foreign player at 3-under 68. (Yonhap News)