Kuwaki added a one-under 70 to her opening 66, reaching six under after two rounds. Thitikul followed her first-round 64 with a two-over 73, making one birdie and three bogeys to finish at five under.
Defending champion Miyu Yamashita made a quadruple bogey at the 18th and shot 77, missing the cut at seven over. Charley Hull posted an even-par 71 to reach two under.