Davies had seven birdies at the 6,506 yard, par 72 Kintetsu Kashikojima Country Club for a one-stroke lead over Japan's Chie Arimura and American Reilley Rankin.
'The wind was a bit tricky,' Davies said, adding that she missed the green on No. 8 because of it. 'The tee is completely in the trees and the green is exposed to the wind. We completely misjudged the wind. But that's about all.'
Australian Karrie Webb, who ended Annika Sorenstam's Mizuno Classic winning streak at five last year, got off to a slow start with a 73. Sorenstam is not competing this weekend.
Davis had birdies on three of the first four holes and finished with five birdies on the front nine, including 20-footer on the par-4, 375-yard third hole.
'It's all about putting for me,' Davies said. ' I normally play solid golf. I hit a high percentage of greens, it's whether I putt well or not. Last week, in Thailand, I putted really well and, today, I putted fantastic.
'I think I had 26 putts, which might be my lowest of the year. The driver's been a big thing. I've been driving so far and pretty straight; I missed a few fairways today, but not many.'
Rankin, who had birdies on Nos. 15 and No. 17, could have had a share of the lead but missed a 2-foot par putt on No. 14.
'It's a tough wind, obviously, it feels like it swirls a lot out there, but I had a great caddy,' Rankin said. 'He did a good job and he just reminded me to trust and trust what (we charted) it says.'