TOKYO, September 25, 2014 (AFP) - The 21-year-old collected five birdies on his front nine to lie two ahead of a chasing pack of five players at the Ohtone Country Club in Japan.
"I got the ball rolling pretty quick," Smith said, adding that he struggled with his irons but made up for it with solid putting.
S.K. Ho of South Korea, Thailand's Namchok Tantipokhakul and Japan's Hiroyuki Fujita, Kiyoshi Murota and Keiichiro Fukabori all shot 68 to share second.
Asian Tour Order of Merit leader David Lipsky had a share of seventh place after hitting four birdies and two bogeys for 69.
"I don't feel like I played great today but I got around by getting an under-par score which is good," said Lipsky.
"My game still feels pretty solid. Everything feels like it's moving in the right direction," the American added.
Scores
66 - Cameron Smith (AUS)
68 - S.K. Ho (KOR), Hiroyuki Fujita (JPN), Kiyoshi Murota (JPN), Keiichiro Fukabori (JPN), Namchok Tantipokhakul (THA)
69 - Scott Hend (AUS), David Lipsky (USA), Adam Bland (AUS), Arjun Atwal (IND), Shinji Tomimura (JPN), Juvic Pagunsan (PHI), Prayad Marksaeng (THA), Marcus Both (AUS), Akio Sadakata (JPN)