Rio Takeda and Eri Okayama shared the lead at 5-under par after the first round of the Women's British Open on Thursday as Japanese players dominated the leaderboard at Royal Porthcawl.

World No. 12 Takeda and 139th-ranked Okayama struck matching 67s on the Welsh coast as compatriot Miyu Yamashita finished one shot adrift.

A large group of players were at 3-under par on a congested leaderboard in the final major of the year.