Luke Donald shot a 7-under 64 to take a four-stroke lead after the second round of the Dunlop Phoenix on Friday.
Donald birdied three holes on the front nine at the Phoenix Country Club and added four more after the turn to finish at 13-under 129, four strokes ahead of Japan's Shunsuke Sonada (66).
Donald, who won the U.S. PGA Tour and European Tour money titles last season, is playing in the Japan Tour event for the first time since 2007.
Japan's Hiroyuki Fujita also shot a 66 to sit in third place, one stroke ahead of compatriot Koichiro Kawano (69).
A group of four golfers, including overnight co-leader Brendan Jones of Australia (72), were tied for fifth at 5-under 137.