HONOLULU, January 5, 2014 (AFP) - "I don't know how many years I've been here. This is seven or eight probably and I've had maybe one or two decent finishes, but nothing so spectacular," Johnson said. "The more I get my feet here walking these grounds, I think the more comfortable I become."
Johnson, a 10-time winner on the USPGA Tour, has a 13-under 133 total at the Kapalua Resort course.
Defending champ Dustin Johnson also shot 66 to reach 10-under and grab a share of second place with Jordan Spieth (70) and Matt Kuchar (68).
Michael Thompson (71) and Webb Simpson (71) are tied for fifth at nine-under, while Kevin Streelman (71) and Ryan Moore (71) are in seventh at eight-under.
Dustin Johnson drove his tee shot on the par-three eighth to within six feet and then made birdie to move into the lead at eight-under.
That was Johnson's fifth birdie in six holes, a stretch in which he made two long putts including one from 27 feet at the seventh.
Zach Johnson drained a putt from 23 feet for his third straight birdie at the eighth to claim the outright lead at 10-under.
"Looking back on it, I just think about the par-fives. I parred every one of them," said Zach Johnson. "I had a three-putt on one of them for par, which can happen. A couple missed opportunities."
He took a two-shot lead after Spieth found a bunker with his second shot at the seventh and could not get up and down for par, dropping him to eight-under.
Thompson moved within a shot of Zach Johnson with a birdie at the eighth, but Johnson quickly regained his two-stroke cushion by rolling in a shot birdie putt at the 10th.
Johnson reached 13-under with a birdie at the 14th and closed with four straight pars.
Scores after the second round of the $5.7 million Tournament of Champions Saturday at the Plantation Course at Kapalua (par 72)
133 - Zach Johnson 67-66
136 - Dustin Johnson 70-66, Matt Kuchar 68-68, Jordan Spieth 66-70
137 - Webb Simpson 66-71, Michael Thompson 66-71
138 - Ryan Moore 67-71, Kevin Streelman 67-71
139 - Brandt Snedeker 70-69, Ken Duke 70-69, Jason Dufner 67-72
140 - Adam Scott (AUS) 70-70
141 - Gary Woodland 71-70, Harris English 70-71, Chris Kirk 66-75
142 - Woody Austin 72-70, Patrick Reed 70-72, Bae Sang-Moon (KOR) 69-73