Mikko Ilonen was in second place, one stroke behind Plaphol, while Shiv Kapur and Mads Vibe-Hastrup were in third place at four-under-par 67. Twelve threesomes were not able to complete first-round play because of a heavy downpour.
Plaphol played in one of the earliest groups Thursday and carded six birdies and 12 pars at the par-71 Damai Indah Golf & Country Club.
"The key here is to keep it on the fairway because the wind tends to pick up in the afternoon so you have to strike it quite accurately off the tee," Plaphol said.
Ilonen had seven birdies in his round but also had two bogeys.