Cool characters, one wearing shades, became joint leaders at the halfway stage of the 62nd US Masters in chilling winds here at Augusta National yesterday. David Duval was first to set the target of 139 - five under par - and was later joined by the 1992 champion, Freddie Couples, from the last group on the course, at the end of a long day.

Despite a nerve-racking wait for those on the borderline, there was no need to bring the 10-stroke rule into play. In fact Darren Clarke, who shot a second round of 73 for 149, was one stroke inside the cut, so joining Joe Carr, Ronan Rafferty and David Feherty as the only other Irishmen to have qualified for all four rounds in this hallowed place.

A further lift for Clarke is that he has been paired with no less a figure than three-times former champion, Gary Player, in the third round today. The weekend's line-up also includes the 19-yearold US Amateur champion Maatt Kuchar, whose father Peter is caddying for him, and the beaten finalist, Joel Kribel.

The crowds rose to a wonderful effort from Jack Nicklaus, who had been honoured earlier in the week to mark his 40th Masters. His walk betraying arthritic hips, the 58-year-old Bear sank a 15foot birdie putt at the last, for a round of 72 and a remarkable total of 145, the same as Ernie Els.

Meanwhile, Tiger Woods had to be content with a seemingly moderate 72, but even at four strokes off the lead, he remained very much in contention, largely because of the nature of his finish. Having driven into a horrible lie in a left fairway bunker at the 18th, he was short of the green in two. But Woods eventually holed a 15-foot putt for what may yet prove to be a priceless par.

For more modest reasons, it was a highly satisfactory exercise for Clarke, who had the considerable satisfaction of carding a birdie on the 17th, which had inflicted an extremely painful seven on him on Thursday. "It wasn't quite what I was looking for coming here, but the fact remains that I have achieved my first objective," he said afterwards.

Play got under way at 7.30 am to allow 10 players finish opening rounds that had to be carried over from Thursday. Among them was Duval. For others, notably former champions Tom Watson, Nick Faldo, Raymond Floyd and Sandy Lyle on 151, the effort of repairing Thursday's damage had become a lost cause, just like the sun's attempts at breaking through a stubborn cloud cover.

Clarke was clearly aware of these possibilities as he contemplated his round. "The course was playing at least a stroke easier than yesterday," he conceded afterwards. "Yet, in terms of ball-striking, my first round was far more impressive."

Somewhat at odds with his game at the moment, he had to be content with what a notoriously difficult course was prepared to concede. And that was precious little. Still, there were four birdies on his card, starting at the long second, which he reduced to a drive, eight iron and two putts from 15 feet.

Clumsy approach play cost him shots at the third and fifth, and again at the tricky seventh. But he made a delightful birdie at the 180-yard sixth with a six-iron to two feet and another birdie at the long eighth with an outrageous 40-foot putt.

Though sensibly cautious on the homeward journey, he still dropped a shot at the 10th and another at the short 16th where he was in two bunkers. But his play of the 17th provided rich compensation in terms of confidence, if not in actual shots.

With the pin tucked menacingly on the front right, he hit a 113yard sandwedge 12 feet past it and sank the putt for an extremely welcome three. "I was pleased with my putting, particularly on the back nine where I was determined to hang on and grind out a score," he said.

Despite the difficulty of the conditions, Duval managed to shoot a 68 and equal the best round of the tournament so far, set by the old walrus, Craig Stadler, earlier in the day. Both of these players showed that how equanimity might be maintained over 18 holes. But many others suffered.

Scott Hoch, who lost a play-off to Faldo for the 1989 title, was the third player to get to five under par yesterday, with birdies at the 14th and 15th. But he threeputted the short 16th for a bogey, missing from the sort of 30-inch distance that had caused his undoing nine years ago.

Then there was Colin Montgomerie, who found himself in the decidedly awkward role as a buffer - albeit a substantial one - between the largely non- communicative Woods and Fuzzy Zoeller. Normally Masters competitors play in two-balls but it was considered necessary to change the format because of Thursday's delay.

In the event, Montgomerie, Woods and Zoeller became natural partners after opening rounds of 71. Relations between the two Americans have been decidedly frosty since an allegedly racial comment by Zoeller regarding last year's champion.

The big Scot was still in touch with the leaders after reaching the turn in 37. But despite a beautifully-saved par after being in Rae's Creek at the 13th, he went on to drop shots at the 14th and 17th for a homeward 78 and a disappointing round of 75.

Jose-Maria Olazabal, the 1994 champion, had a similarly frustrating round. Having improved his overnight position to three under for the tournament after a birdie at the short fourth, he was eventually knocked back to level par by bogeys at the 11th and 12th.

But just as Woods achieved a crucial par at the 18th, Olazabal breathed new life into his own challenge by his play of the treacherous 15th. There, a beautifully-controlled sandwedge pitch came to rest five feet below the hole and he sank the putt for a birdie four to get back into red figures, alongside the champion.

The 500-yard 15th became something of a terror over the last two days. This was due largely to the fact that it was playing into a strong wind which meant that it was borderline for those aspiring to reach it in two, while accurate pitching was also hazardous.

Against that background, Duval's play was most impressive. His only bogeys were at the long second where he missed from less than three feet and at the 12th, where a seven-iron tee shot found the back bunker. There was generous compensation in six birdies, four of them in the last six holes.

For his part, Couples loped along in his usual, laid-back fashion. The key hole for him was the 12th, where a 10-foot birdie putt got him back on track after potentially dispiriting bogeys at the 10th and 11th.

Generally, however, an elite field contrived to lend telling emphasis to the notion that the best way to throw a scare into a professional, is with wind and water.