Kyung-Ju Choi, better known in the golfing world as KJ, holed a 25-foot putt on the final green yesterday to be the only player out of the 156 starters to be under par at the halfway stage of the 137th Open Championship.

A three-under-par 67 in wet and windy conditions gave him a one-under aggregate of 139 and a one-stroke lead from 53-year-old Australian Greg Norman.

Choi, with Perthshire-based Englishman Andy Prodger as caddie, is bidding to become the first Asian winner of the Open. If you classify Fiji's Vijay Singh as Oceanic, he is also in position to become the first Asian male winner of any major championship.

The son of a rice farmer, he was born on the island of Wando, which did not have a golf course as he was growing up and he took up weightlifting instead. He didn't take up golf until he was 16 on the advice of a school athletics coach.

Now based in Houston, Texas, the 37-year-old carries the burden of expectation of a nation whose women are leading the way in golf.

Pioneered by Se Ri Pak, a total of four have won women's major championships.

Choi's English is improving, but yesterday he chose to conduct his news conference through an interpreter. "If I were to win this, the reaction back in Korea would be tremendous," he said. "It's a major tournament and I know a lot of people are praying for me back home."

After his late introduction to the game he improved rapidly, moving to the Asian Tour and eventually gaining his card to play on the PGA Tour in America nine years ago. He has won seven times since and recently moved from Florida to Houston where there is a larger Korean community.

"There is a good Korean church there," he said. "The education for the children is wonderful and travel-wise it makes sense to be in the middle of the US. Houston is like my second home."

Prodger is a former caddie for Nick Faldo and won two majors with him, the 1987 Open at Muirfield and the 1989 Masters. "Andy is like my big brother," said Choi. "He makes me feel relaxed and comfortable. We make a good team. In pressure situations he'll say something that makes me laugh. He has a lot of experience and when my tempo is too fast he relaxes me."

Ranked world No.11, Choi said that links golf suits his eye. "When I stand on the tee box I can see everything. It's very easy for me to set a target and just go with it," he said.

"This is probably the best round that I have ever played at the Open. Everything worked the way I wanted it to," added Choi, who made his Open debut at this venue in 1998.

He began with a bogey on the first and made his move with birdies on the third, 13th, 17th and 18th, clenching his fist to celebrate his first career lead in a major.

His best major outing was third at the Masters in 2004, while he was tied eighth in last year's Open at Carnoustie. He said lessons learned from those experiences will help.

Camilo Villegas, the 26-year-old Colombian, had the low round of the day, a five-under-par 65, to move into third place on 141, while Scottish Open champion Graeme McDowell of Northern Ireland, the joint overnight leader, remained in contention in joint fourth place on 142 after a 73.

The halfway cut fell at nine-over-par 149 meaning Paul Lawrie, Scotland's 1999 Open champion, missed out by one shot alongside five-time Open champion Tom Watson, while Mark O'Meara, the champion at Royal Birkdale in 1998, was two too many.

Yesterday's attendance was 44,000, bringing the total to 117,000, a drop in 4500 from 1998, accounted for by the poor weather that is set to continue today.