Bill Haas, overnight leader, loses further ground on Bubba Watson with a bogey on the first. He is back to three under, meaning Kevin Stadler is on his own as the closest challenge to Watson.

Freddie Couples birdies the second to move on up to two under and Thomas Bjorn's birdie on the last puts him in the clubhouse on three under.

Former champion Bubba Watson's eagle putt skates across the top edge without dropping, but he has a tap-in on the way back to make a birdie and is up to five under and clear of the rest.

Luke Donald picks up a shot as well. The former English world number one is five over and fighting hard. He is two under for the day.

South Korea's KJ Choi is in business. A birdie at the first move him to three under and a share of fourth.

Everyone crowd round, quick! Eagle chance in the offing. Bubba Watson, after taking the racing line through Amen Corner, hits his second to within eight foot on the par-five 13th. Drain it and he moves to six under and two shots clear of the rest. At the very least he is going to be taking sole possession of the lead.

Rob Hodgetts
BBC Sport at Augusta National

As an Englishman with a sense of decorum, Augusta's seat-saving etiquette is beginning to trouble me. I'm worried the system designed to be fair to all is in danger of abuse.

There is a trend for those in seats near the ropes to stand up as the players approach, thus blocking the view.

When Ernie Els stuck his approach to seven into the front row - needing PC Plod to cut the rope with his handy knife to make space - those in the first couple of rows (and the chairs were 12 deep) stood up.

A few protests ensued but this being Augusta no-one is going to get ugly so they have to grin and bare it. It's just not cricket.

-4 B Watson (US) after 12, K Stadler (US) 7, Haas (US); -3 Blixt (Swe) 7, Choi (Kor) 1, Scott (Aus).

Selected others: -2 Snedeker (US); -1 Gallacher (Sco), Oosthuizen (SA) 16, McIlroy (NI); +1 Westwood (Eng) 9, Donaldson (Wal); +2 Rose (Eng) 9, McDowell (NI) 2; +3 Garcia (Spa) 12; +4 Clarke (NI), Mickelson (US) 9; +6 Donald (Eng) 12

England's Lee Westwood has been steady and solid so far. He is level par through the turn for a score of one over overall.

Scotland's Stephen Gallacher is back in the clubhouse at one under par following a level-par. That round featured a monster 342-yard drive, clear over the back fence, car park and into the town centre at your local range. The longest of the second round so far.

Joining him at the bar, but only for a mineral water in these slimmed down days is Darren Clarke. The Northern Irishman is done and dusted at two over for the day and four over for the campaign.

Out in the fray, Phil Mickelson drops a shot at nine to go to four over. His attack-everything approach is looking more courageous than wise at the moment.

Image source, Golf Week

"God could use you today, don't give up," said 1970s Masters champion Billy Casper as he stood over the death bed of Clebe McClary. The Vietnam War amputee was "ready to die" according to doctors, but he now cites Casper's words as the moment which saved his life. It took 46 years for the pair to meet again, but at Augusta this week, thanks to Jay Haas, dad of current tournament co-leader Bill, they did,, external with emotion very much to the fore.

"I'd given up," said McClary. "I wanted to die, and I'd have died right there if not for him."

Scandinavian woe. Sweden's Jonas Blixt drops out of the leading group with a bogey on the seventh before Denmark's Thomas Bjorn's little run comes to a grinding halt with a bogey on 17.

Sergio Garcia's birdie putt trickles just wide. The Spaniard is sporting some spanking pink strides though which will be some consolation to him.

Now it is Bubba Watson's chance to pot for a birdie to climb back in amongst the leaders. There she blows and down it goes for the 2012 champion. He is back up to four under.

And even Luke Donald escapes with a par from the sand. A happy trio all in all.

Sergio Garcia becomes the first player of the day to birdie the 11th and he is safely on the green at 12. Could be a chance to nibble a little more off that three over score.

The Spaniard is outshone by playing partner Bubba Watson who lands with the precision of a smart bomb right in the guts of the green. But you get the feeling it's just not Luke Donald's year, again. His ball lands no more than one yard from where Garcia's did, but the Englishman is in the bunker at the front of the green.

Justin Rose chips in from way out west on the eighth for an eagle three. That takes him to two under for the day and two over overall.

Elsewhere fellow Englishman Ian Poulter is also improving on his first round, picking up a birdie at the first to move to three over.

Marc Leishman, a leader just a short couple of hours ago, is sinking fast. The Australian's double bogey on the ninth is followed by another shipped shot on the 10th. He is one over overall.

Going the opposite way at a rate of knots is Thomas Bjorn. The Dane picks up successive birdies on 14, 15 and 16 to move to three under for the tournament. Just a couple of holes to play and if he could see this one home he will be well placed for a crack at the last two rounds.

Iain Carter
BBC golf correspondent

Oosthuizen implosion on 15. Third shot into the water, fifth onto green, sixth putted short, seventh raced by, eighth into hole. Back to -1.

Hang on. Where has he gone? Louis Oosthuizen drops off the leaderboard radar in spectacular fashion. From a four-way share of the lead, he is back behind a whole host of other contenders after an eyesore 15th. And Iain Carter was there on the par-five hole to sketch out the full horror.

The par-three 12th is befuddling the best of them. Jason Day, Dustin Johnson and Henrik Stenson all miss the dance floor landing in the water, in the sand and out the back.

Derek Ernst gets his first and possibly last Masters 2014 shout-out as the American, making his first appearance at Augusta, chips in from off the green to take an eagle three at 13. That takes him down to seven over, right on the watershed of that projected cut.

Now here's a thought: imagine Augusta as a Ryder Cup host course. Wonder what chairman Billy Payne and co would make of that?

Andy Kershaw:, external I think Augusta would be a fantastic venue for The Ryder Cup! Is that ever a possibility?

I'm not sure that the Augusta National member would enjoy the essential whooping and hollering of Ryder Cup golf.

Image source, BBC Sport

Among the range of prohibited items for spectators at Augusta are mobile phones, so throughout the week the public telephone boxes (remember them…) near the 18th tee have been in high demand.

It is probably the only major public event safe from a cringey staged selfie nowadays., external