A logjam of 10 players, including South Korean golfer Hwang Inn-choon, were tied for third at 4-under 68 and another 11 were at 3-under 69 in the first European Tour event played in South Korea.
Ilonen, playing in the morning group, jumped to the lead with two birdies in his first three holes. He went to 3-under at the sixth hole, but gave a stroke back at No. 7. He then had birdies on three of his next four holes to get to 5-under. He had six pars to finish his round.
Carolan also started strong, getting to 3-under after just four holes. A birdie at No. 9 allowed him to make the turn at 4-under. He ran off six consecutive pars before a birdie at the par-5 16th gave him a share of the lead.