Ryu, a former US Open Champion, has yet to win this season but has recorded nine top tens and with this sort of lead it is hard to imagine how she will be chased down over the weekend.
Ryu made mention of the fact that she had been working with David Stockton to improve her putting. "Yeah, not every round, but sometimes I text with him. But every time just he told me to trust yourself and get relaxed. He really was not talking about any skill things. Just talked about my mental ability thing. So I'm just going to stick with what he told me, and I'm just going to relax and have fun with my golf."
Cristie Kerr is 5th while last week's playoff loser and former winner of this event, Brittany Lincicome, is tied for 6th with a group of players including the improving Australian Lindsey Wright.
Wright added a round of 69 to her opening 67 to be just two shots from second position.
Two time winner, Lydia Ko, is in 24th position as he chases a three-peat in the event but give she is ten shots from the current leader she faces a big task if she is to have any chance.
Karrie Webb and Sarah Kemp were other Australians to make the cut