The field for tour's season-ending tournament includes its top 32 players of 2007, and will be reduced to 16 players Friday.
"To have even made it and be one of the top-32 in the field in is a pretty awesome feat," Christina Kim said after a round with one eagle and no bogeys. "I'm pretty proud of myself for even getting here."
"My swing is working good, and my short game is good," said Mi Hyun Kim, who is not related to Christina Kim. "I had five birdies (on the front nine). I have more chances at birdie, but I didn't make the putts. But I like that score."