South African Keith Horne, Dan Jeppe Huldahl, Belgian Nicolas Colsaerts and Frenchman Grégory Havret were all tied on 12 under par - with another nine players queuing up within two shots of the lead.
Horne still had four holes of his opening round to complete when he returned to the course, and two birdies saw him snatch the first round lead off Han Chang-won.
The 39 year old began following up his opening 63 with back-to-back birdies, and having dropped his first shot of the week at the 14th - his fifth - responded with a birdie three holes later.
An inward 35 secured a round of 69 to join an increasingly bunched group atop the leaderboard.
"Yesterday I got off to a great start with birdies on the first four holes and kept going from there," he said.
"It's the sort of course you can get going on. There's not much to scare you out there. If you get the irons and putter going you can get a good score."
Of the four, Havret was first to finish, the US Open Championship runner-up completing a second consecutive round of 66.
"I had a good round," he said. "I birdied 16, 17, 18 then one and three so five under for six holes was the key.
"I've not played bad this year - a couple of top 20s in Middle East and third in India, bit disappointed to miss the cut at the Masters. The game is pretty much there. I just need to get some iron shots going and I did that today."
Big-hitting Colsaerts started his round with successive birdies, and not surprisingly picked up shots on both par fives on the back nine in his 67.
"I closed well this morning - an eight foot putt with one hole to go and made birdie and then made birdie on the last," he said. "That set the tone for the rest of the day and I birdied the first two on the round that followed. I just kept hitting greens and was very close to the flag."
Former Wales Open champion Huldahl signed for a 65 that included no fewer than eight birdies, which he put down to some good work on the greens.
"I holed a lot of good putts this week - that's the key," he revealed. "You still have to make the birdies on the course it's not really easy.
"There's been a few highlights. I hold a nice one on 18 which is always nice to finish. It makes everything so easy when you are putting well."
Amongst those tied for fifth and only one off the lad is Spain's Sergio Garcia, who highlighted his recent improvements by reaching the halfway stage without a bogey.
"Every time you have a bogey-free round is good, it doesn't matter how easy the course is, not having a bogey on the card is difficult," said The Ryder Cup star. "It means my game is solid and I've got some good up and downs when needed.
"I left some birdies out there - more yesterday than today but overall it is a good start and hopefully I can have a similar weekend."
He was joined by Dutchman Robert-Jan Derksen and Swede Fredrik Andersson Hed, while of those on the course 19year old Han was best placed at ten under with eight to play, the Korean two under for his round.