Defending champion Seo Hee-kyung shot a four-under-par 68 to claim a one-stroke lead after the first day of the Korean Ladies Masters.

Seo shot five birdies against just one bogey at Cypress Golf & Resort to move ahead of compatriots Sarah Lee, Kim Hyun-ji, Lee Bo-mee and Australian Anna Rawson.

"I have gained more confidence since last year because this year I have won four more tournaments," said Seo.

"I feel my game is in good shape."

European number three Becky Brewerton, the top ranked player at the event, was in a tie for 15th at one over.