A stunning 65 in Japan leaves him in good shape for the weekend.
Shane Lowry has found his feet at the Olympic Games and has made a strong move on day two.
Seven birdies and one dropped shot dotted a card of pars as the Clara golfer shot up the leaderboard.
Those birdies came on 2, 6, 7, 8, 13, 14 and 16 with the only blemish occurring on the 9th hole.
A superb wedge into 17 could have eeked out an extra shot under par but Lowry edged a very make-able putt.
He's signed for a round of 65.
Rory McIlroy is also well in contention.
He bogeyed the closing hole to shoot a 66 but also sits on -7 and in a tie for fifth.
Mexican Carlos Ortiz leads on 10-under after 13 holes of his second round.