World No.1 Scottie Scheffler, making his debut in the tournament at TPC Twin Cities, is three shots back, tied for fifth after his bogey-free 65.
Scheffler started his round at No.10 and was two under on the back nine with birdies at Nos.12 and 18, then heated up with birdies on the first, fourth, sixth and seventh.
Kohles, 36, is ranked No.128 in the world and seeking his first win on the PGA Tour. He finished tied for third at the John Deere Classic on July 5.
He birdied the second, sixth, eighth, 10th, 12th, 14th and 15th, then made eagle on the par-5 18th. Kohles ranked first on Thursday in greens in regulation (17 of 18), tied for third in driving accuracy (12 of 14 at 85.7 per cent) and ranked 39th in feet of putts made (82 feet).
Jackson Koivun, Gary Woodland and Argentina's Emiliano Grillo are tied for second after each shot seven-under 64.
Scheffler is tied at six under with Lucas Glover, Michael Brennan, Kevin Roy and Sweden's Jesper Svensson.
Defending champion Kurt Kitayama is tied for 26th at three-under 68. He opened with the first of his seven birdies, including at the first and last, but was undermined by a bogey at the par-4 third and a triple bogey at the par-4 ninth.
One of the unluckiest players on the day was Jake Knapp who was robbed of a hole-in-one after his ball sat next to the hole and refused to go in after hitting the flagstick.
Karl Vilips and Cam Davis, the two Australians in the field, have plenty of catching up to do.
Vilips is tied 43rd after making a two-under 69, while Davis is at even par.
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