The South Korean, one of only three players not to card a bogey in difficult conditions, holds a one-shot lead over Jamie Donaldson of Wales and Finn Mikko Ilonen going into the final round.

Blustery breezes made the links-style holes particularly difficult for the players. Toughest of all was the 492-yard par-4 18th, playing straight into the wind.

Several players strayed into fairway bunkers, while US Ryder captain Corey Pavin took his driver off the fairway but still pulled up short.

Thailand's Thongchai Jaidee probably lost his chance of the title when he needed three shots to move his ball out of the rough on the right.

The lead changed hands throughout the day, with Yang, Donaldson, Ilonen and overnight leader Kim Do-hoon of South Korea all finding themselves on top.

The low round of the day came from Welshman Rhys Davies, whose bogey-free 65 included eagles on both the par-5s on the back nine and lifted him 53 places up the leaderboard. At eight-under-par he is six shots off the lead.

Countryman Stephen Dodd, who was playing alongside European Ryder captain Colin Montgomerie, was the day's other player to avoid a bogey and climbed the leaderboard with a 66 that left him tied for fifth with Kim on 10-under.

Meanwhile in Atlanta, a grueling Masters finally caught up to K.J. Choi at the Verizon Heritage, and Jim Furyk, Charles Howell III and Greg Owen took advantage to share the lead after Friday's second round.

All three were level at 7-under 135, a stroke ahead of a group that included two-time Verizon champ Boo Weekley and Stuart Appleby.

Choi, who played alongside Tiger Woods all four rounds at Augusta National, opened with a 64 on Thursday. However, he couldn't maintain that pace and fell three shots off the lead after a 74 at Harbor Town Golf Links.

The world's sixth-ranked player missed the Masters' cut for just the second time in 14 appearances. Furyk wasn't happy with the early exit. But instead of dwelling on it, he enjoyed what was left of Masters week.

Furyk stuck approach shots within 10 feet on the 13th and 15th holes for birdies. He caught Choi for the lead when he chipped in from just off the green on No. 16.

Furyk, whose round ended just as Choi teed off, expected the South Korean to continue the strong play from last week, when large galleries that followed the group on Augusta's grounds.

Choi, though, quickly fell back on Friday when he drove out of bounds on No. 11, then put a tee shot in the water on No. 14, both for bogeys.

After a double-bogey 6 when he failed to get out of a bunker on No. 18, Choi trailed by three. He held things together with an even-par final nine to remain in contention.

Howell moved level with Furyk with a birdie on No. 18, rolling in a 22-footer from off the green. “Sometimes it's better to be lucky than good,” he said.

Owen moved to 7 under after putting his approach on the par-5 fifth hole within 2 feet for birdie, then made par the rest of the way.

The most intriguing surges may have come from Weekley, Appleby and 18-year-old US Amateur champion An Byeong-hun.

Weekley turned into a golf folk hero with wins here in 2007 and 2008, fans drawn to his folksy demeanor as much as his game. An injury last year at The Players Championship led to a month off and problems once he returned.

Weekley hoped his favorite tour venue might provide the missing spark to his game. It looked it had so far.

He posted his second 68, the first time all year he opened with two sub-70 rounds.

This is An's third PGA Tour event after missing cuts at the Arnold Palmer Invitational and the Masters. He used an eagle on the par-5 15th and birdies on the fifth and sixth holes to move within a stroke of the lead. However, he went 3-over par his final three holes to fall back.

Appleby hasn't played Harbor Town since 1998 when he felt it wise to take a break after typically stressful Masters.

Appleby didn't qualify for Augusta National this time, opening a week on his schedule.

Still, Harbor Town has never really suited Appleby - until now.

The 67 was his lowest round of the year. It's also the first time in 11 events this season he's had two rounds in the 60s.

Furyk knows Harbor Town's Jekyll-and-Hyde nature too well.

He was second at the Verizon Heritage in 2005 and 2006, and fourth two years ago. Then again, he also missed cuts here in 2007 and 2009. “It seems to be feast or famine for me,” he said. “Hopefully, this year it's feast.”