Akie Iwai of Japan shot a 9-under 63 on Thursday to lead the first round of the LPGA's Toto Japan Classic.
Iwai recorded a birdie on each of her first three holes before settling for a bogey on No. 4. She added another birdie on No. 9 and an eagle on No. 12 before finishing with four more birdies to tie the tournament 18-hole scoring record.
"Not only the fairways and greens but also the rough are very beautiful this week. I like it very much, and it makes me feel like I could play well this week," Iwai said of her record-tying round. "It is going to be a very tough birdie-chasing game this week, but I want to build a new record."
The last golfer to card a 63 at the Toto Japan Classic was China's Shanshan Feng in 2017. Feng went on to win the event.
Three other Japanese players -- Nasa Hataoka, Yuna Nishimura and Mone Inami -- were a stroke back after rounds of 64 at the Taiheiyo Club in north central Japan.
Hataoka, a six-time winner on the LPGA Tour, finished with three straight birdies and made six birdies on the back nine overall to offset a bogey at the par-3 13th hole.
"[On No. 18] I was trying for two-putt, save par, but it was a good line and it just [got] in," Hataoka said. "... [On the] 17th hole, it is short par-5 so that hole I really want to birdie, but on 16, par-3, was good 6-iron tee shot and I hit it good."
Nishimura's 64 tied her career-low round on the LPGA Tour.
"Actually I'm struggling in my first year as a rookie, but I'm now pretty confident to play here and I'm trying to concentrate on the CME Globe at the end of the season." Nishumura said.
China's Yu Liu and Japan's Shiho Kuwaki each finished at 7 under, while China's Xiyu Lin and Japan's Sora Kamiya and Hikaru Yoshimoto are at 6 under in a tie for seventh place.
Defending champion Gemma Dryburgh of Scotland was four back after a 67. American Rose Zhang was four back after shooting a 68.
Dryburgh's victory last year was her first on the LPGA Tour. She received a special prize, a toilet, from the Japanese sponsor Toto, which makes bathroom appliances and fixtures.
"Hoping for another one of these to add to the collection!" she said on Instagram while posing Tuesday with the sponsor's products.
Dryburgh said the victory a year ago changed her career.
"I know I can compete out here and win also," she said. "Competing under that pressure, seeing the shots that you can do under that pressure as well, it gives you a lot of confidence."
The Associated Press and Reuters contributed to this report.