Former champion Kim A-lim fired six birdies in a 4-under-par 68 to headline a group of six players tied atop a log-jammed leaderboard after the first round of the 80th U.S. Women's Open on Thursday.

Fellow South Korean Im Jin-hee, Rio Takeda, Americans Yealimi Noh and Angel Yin and Spanish LPGA rookie Julia Lopez Ramirez shared the lead, one stroke in front of a group of five players tied at 3-under.

Another seven players were two adrift, but Kim said she wouldn't expend her energy worrying about who might be in striking distance.