Australian No.1 Minjee Lee is two strokes off the lead after the opening round of the LPGA Tour Toto Japan Classic thanks to a bogey-free circuit of the Seta Golf Club.
Lee carded a five-under 67, birdieing two of the last three holes to be within range of outright leader, Korean world No.3 So Yeon Ryu.
She has a one stroke lead over compatriots Jiyai Shin, In-Kyung Kim and Japan's Nasa Hataoka.
Lee was in a tie for fifth alongside another Korean Sei Young Kim with two rounds of the 54-tournament remaining.
Ryu had five birdies on the last eight holes to underscore her impressive start.
"For a three-round tournament, you're better to make sure you have a really, really good starting day," she said.
"My short game was really great today. I putted really well," she said.
"I was struggling with my putting the last two weeks in Taiwan and Shanghai, but I'm so glad my putting worked well."
American Mo Martin provided a highlight with a hole-in-one on the ninth - she used a 5-wood on the 178-yard hole to finish with a 69, four shots off the lead.
"It landed just a couple feet short and it was just perfect," Martin said.
"The greens are really receptive, it just landed perfectly and then just skipped in there."
Sarah Jane Smith, the other Australian in field, signed for an even par 72.
The LPGA stop in Japan is the fourth of five consecutive tournaments across Asia.
