The home favourite, who didn???t pick up a golf club until he was 22, fired eight birdies in a six-under 66 to set the early pace at Genzon GC, with four players a shot back tied-second.
America???s Peter Uihlein struck a back nine 31 to stay within one of the lead, firing five birdies on his back nine to join Thailand???s Kiradech Aphibarnrat and Byeong Hun An, who made a hole-in-one at the par-three eighth, on five under.
Uihlein finished with a flourish by making three successive gains, holing from six-feet at the 16th and 15-feet at the last, as well as tapping-in the 17th after almost holing from out of a bunker.
???I???m definitely pleased,??? the former Madeira Island Open champion said. ???I feel like I did a lot of things really, really well and I felt like I did some of my old habits and hit a couple squirrelers, but I’m pleased with five under.???
Aphibarnrat looked set to threaten the outright lead after completing the front nine in five under, but was only able to complete his second nine holes in regulation following a bogey at the par-four 14th to sit alongside Felipe Aguilar and ace-maker An.
The Korean saw his iron shot at the 226-yard eighth pitch a couple of feet short of the flag and roll in to the cup, one of two holes-in-one during the opening round after Denmark???s Morten Orum Madsen holed his tee-shot at the 12th for a second ace in as many tournaments.
A strong back nine from South Africa???s Darren Fitchardt leaves him outright sixth, while two-time European Tour winner Andy Sullivan opened with a three under 69 in his first sub-70 round since winning February???s Joburg Open.
Joining Sullivan three shots back included Anthony Wall, Matt Ford and Ross Fisher, while Frenchman Rapha??l Jacquelin, making his 500th European Tour appearance, recovered from a double-bogey at the par-five fifth to card a one-under 71. ??
Watson, the highest ranked player in the field and the only to have appeared at Augusta last week, was one-over through 12 after opening his back nine with consecutive bogeys but rallied with a hat-trick of gains from the fifth.