Colomo had six birdies over his final eight holes for a first-round score of 6-under-par 64. He's one stroke up on Miguel Angel Jimenez, who closed with two bogeys, and Andrew Dodt, who had three bogeys Thursday. Jimenez and Dodt are at 5-under 65.
Five players, including Jose Maria Olazabal, are tied for fourth at 4-under.
Defending champion Rory McIlroy was at 1-over 73.
A handful of golfers -- none of whom was better than even par -- were unable to complete their first rounds Thursday due to darkness. They are scheduled to do so before the second round tees off Friday.
Colomo started Thursday's play at the 11th hole of the Hong Kong Golf Club and opened with 10 consecutive pars. He had birdies at Nos. 3 and 4 and jumped up the leader board with three consecutive birdies over 6-8. A closing birdie at No. 10 resulted in the day's best round.
Jimenez started with three birdies from Nos. 11-13 and was 5-under after birdies at 17 and 18. He eventually got to 7-under before sliding back with bogeys at the ninth and 10th holes.
Dodt had four birdies on each side but also had bogeys at the 15th, first and ninth holes.