Brian Harman is alone in third place at one-under-par 139 after a second-round 68. Jon Curran posted a one-under 69 on Tuesday and holds fourth place at even-par 140 at Columbia Country Club.
The top-64 after Tuesday's second round of stroke play advanced to the match- play segment, which begins Wednesday. There was a playoff for the final five spots between nine players Tuesday and Charlie Hendrickson, Kyle Davis, Justin Hull, David Dragoo and Jesse Speirs moved on in the championship.
Song Jeon, Brett Lange, Brian Ottenweller and Derek Tolan, who played in the U.S. Open at Bethpage Black last year, were eliminated from this year's championship.
Kang mixed five birdies, a bogey and a double-bogey on Tuesday while Kizzire collected four birdies and four bogeys for his even-par 70.
Harman is looking to avenge last year's disappointing loss in the quarterfinals of the match-play portion of the event. He was 2-up with three to play against eventual champion Charlie Beljan but lost in 21 holes.
'I had my heart broken last year,' said Harman. 'I want to win. As long as you get into match play, that's all that's important. I've seen way too many No. 1 seeds get beaten early.'
Juan Candela and Zechariah Potter share fifth at two-over-par 142, while Scott Barton and Will Osborne are tied for seventh place at three-over-par 143.
The first round of match play is scheduled for Wednesday, the second and third rounds will be played Thursday, the quarterfinal and semifinal matches are on Friday, and the 18-hole championship final is scheduled for Saturday, July 26.
The Junior Amateur is one of 13 championships conducted annually by the United States Golf Association each year, 10 of which are strictly for amateurs.