Tetsuji Hiratsuka took advantage of the greens softened by rain to shoot an 8-under-par 64 Thursday and set the early pace at the Yomiuri Open.
Hiratsuka, who has won two tour events in his seven-year career, carded an eagle and seven birdies against a bogey at Yomiuri Country Club en route to taking a one-stroke advantage over Ryoken Kawagishi and Nozomi Kawahara.
Hiratsuka started on the 10th hole and eagled the par-5 16th while finishing the day with four straight birdies.
"Shots tended to stop on the greens because of the rain and the color of green I saw along the course was beautiful," Tamura said, also giving much of the credit for his score to good course conditions.
Kawagishi and Kawahara matched each other with seven birdies and no dropped shots in 65s.
Satoru Hirota, Shigeru Nonaka and Koichi Kashimura followed with 66s.
Tour veteran Masashi "Jumbo" Ozaki had a 4-over 76 and is in danger of missing the cut in his 1,000th tournament as a professional.
The 100 million yen tournament offers the winner's check of 20 million yen.