“I was pretty upset after the three-putt bogey on the ninth,” Shibuno said. “But after the second shot on the 10th hole, I was able to bring myself back.”

Buhai stumbled with three bogeys in five holes. A 30-year-old South African who has never won on the L.P.G.A. tour, she had a 72 and dropped to second at 12 under.

“I played my first nine holes probably the best ball-striking I could have had — hit really good shots,” Buhai said. “Turned two under, birdied my 10th to go to three under and hit two poor wedge shots on 11 and 12, normally my strong point. Let the three-putt rattle me on No. 12.”

She added: “I’m still here, two shots behind going into the final round playing in the final group. If you told me at the beginning of the week, I would have taken it.”

Second-ranked Sung Hyun Park was a further shot back after a bogey-free 68.

Top-ranked Jin Young Ko and two Americans, Morgan Pressel and Lizette Salas, were tied for fourth at 10 under. Ko (68) is seeking her third major title of the year after winning the Evian Championship last week in France and the ANA Inspiration in April. Pressel had a 66, and Salas shot a 70.