Four tied at the halfway point in Sanya

SANYA, China — American Michael Perras fired a tournament low, 9-under 63 to move to 12-under early in the day, and fellow countrymen Trevor Sluman (65) and Matt Gilchrest (68) and Japan's Yuwa Kosaihira (64) joined him after the second round of the Sanya Championship. They lead a pair of Americans, Christopher Hickman (65) and Max McGreevy (67) by a shot heading to the weekend.