Miyazato twice had runs of three consecutive birdies in her round and moved from a tie for 16th after the first round to a one-stroke lead after Friday's play. She is at 10-under 134 after 36 holes.
Choi Na-yeon turned in a 4-under 68 in the second round and is in second place at 9-under for the tournament. First-round co-leader Yoo Sun-young was 2-under Friday and is in third at 8-under.
Suzann Pettersen, who was tied for the lead after the first round, shot 1-under 71 Friday, and is among those tied for fourth at 7-under. Ryo So-yeon, the third first-round co-leader, was even Friday and is tied for seventh at 6-under 138.
Miyazato opened with a birdie but immediately had a bogey at the par-5 second hole. She moved up nicely with three consecutive birdies over Nos. 5-7 and added another at the ninth hole. She had three more birdies over 12-14 and closed with another at 18.