A total of 43 players in the field of 60 shot par or better in the opening round of the first of three LPGA consecutive events in Asia.
Young played bogey-free golf and Castrale overcame one bogey with eight birdies. They are tied for first at 65 after the first round in the $1.3 million, 54-hole event. Meene Lee was in third place at 6-under 66, followed by Hee Won Han in fourth with 67.
The tournament is being played at the Amata Spring Country Club, which features a true island green. Players must be ferried by boat to the 17th green.