JAKARTA, May 3, 2013 (AFP) - Seven birdies left him with a two-day total of 10-under-par 134, while Australia's Scott Barr trailed by two in second place after shooting his second successive 68, at the US$750,000 Asian Tour event.
Australia's Wade Ormsby was in third position on 137, while reigning Open Championship winner Ernie Els shot 70 to take tied fourth place with Hung Chien-yao of Taiwan and Australians Kieran Pratt, Jake Higginbottom and Scott Hend.
Thongchai, who has four top 10s this season, wielded a hot putter as he continues his search for a 14th Asian Tour victory.
"My wife and two sons are here with me this week. My oldest son followed me for nine holes today but my youngest is at the hotel. I'm very happy with my family support," he said in an Asian Tour press release.
A top-three result at the Royale Jakarta Golf Club will push him inside the top 60 on the Official World Golf Rankings, giving him a strong chance to qualify for the U.S. Open next month.
Els endured an energy-sapping day but remained confident he was still in contention.
"Today was a bit of a jetlag day for me. I was trying to get some energy going. Hopefully I will have more energy tomorrow. I think my game is all there. I just need to get a bit sharper mentally," said the four-time Major champion.
"I just need to eliminate some really small mistakes. This is the type of course where you can get a little bit aggressive."
Scores after round 2: (par 72)
134 - Thongchai Jaidee (THA) 69-65
136 - Scott Barr (AUS) 68-68
137 - Wade Ormsby (AUS) 69-68
138 - Kieran Pratt (AUS) 70-68, Jake Higginbottom (AUS) 69-69, Hung Chien-yao (TPE) 70-68, Ernie Els (RSA) 68-70, Scott Hend (AUS) 66-72
139 - Chapchai Nirat (THA) 71-68, Shiv Kapur (IND) 70-69, Bernd Wiesberger (AUT) 67-72, Daisuke Kataoka (JPN) 70-69