Hidemasa Hoshino fired an 8-under par 64 to take sole possession of the lead after the first round of the Sun Chlorella Classic on Thursday.
Teeing off on the back nine, Hoshino drained nine birdies against one bogey en route to taking a three-stroke lead over his nearest challengers at Otaru Country Club.
Hoshino, who is gunning to claim his second title on the Japan men's tour and first since winning the Chunichi Crowns in 2003, made four birdies before making the turn and birdied five of his last seven holes in a brilliant display of putting.
Keiichi Fukabori, Kaname Yokoo and Satoru Hirota were another three strokes back in a share of second after shooting 67s.