Kim holed out from 123 yards for eagle on the par-4 fourth hole and had seven birdies. He had a four-stroke lead over Callum Shinkwin of England, Thomas Rosenmueller of Germany and American Peter MalnatiÂ
"The hole-out on 4 definitely kick-started the morning," Chan said. "I'm really proud of how I played today."
An eight time winner on the Japan Golf Tour, the 35-year-old Kim is chasing his first PGA Tour title. Born in South Korea, he grew up in Hawaii and played at Arizona State.
"I've missed the last six out of seven cuts, so that's a good feeling to kind of not have to really worry about it." Kim said. "But, obviously I would love to still play pretty aggressive and see if I can shoot another couple low ones."
Shinkwin also eagled a par 4, holing out from 107 yards on the 12th.
"I didn't make any mistakes, which is obviously key," Shinkwin said. "It's very easy to lose concentration in the heat."
The tournament winner will receive a two-year exemption and a trip to the PGA Championship next year but is not in the Masters from winning. No one in the field is in the British Open next week.
Steven Fisk, playing in the final group off the first tee, was five shots back at 66 with Troy Merritt, Angel Ayora, Cristobal Del Solar and Kevin Kisner.
Emiliano Grillo opened with a 67, four days after losing in a sudden-death playoff to Brian Campbell in the John Deere Classic.
Australians Aaron Baddeley (73) and Jason Scrivener (74) are in the lower half of the field.
