Four tied at the halfway point in Sanya

Kosaihira, who finished fourth on last year's Order of Merit, was also bogey-free and shot eight birdies in a solid round as he looks to win on this Tour, just one week after his good friend and compatriot Taihei Sato became the first Japanese player to win in the Tour's history.

"I played really well today. I'm going to keep fighting and hopefully I can get my first win on this Tour this weekend."