INCHEON (Yonhap News) ― Two South Koreans were among the four co-leaders on Friday after the opening round of the nation’s only LPGA Tour event.

Amy Yang and Park Joo-young each shot a 5-under 67 to open the LPGA KEB-HanaBank Championship on the Ocean Course at Sky72 Golf Club in Incheon, 40 kilometers west of Seoul. They were joined by former major champion Anna Nordqvist of Norway and two-time LPGA winner Katherine Hull-Kirk of Australia.

On a warm, benign day ripe for scoring, Park, a younger sister of two-time LPGA champ Park Hee-young, scored six birdies against one bogey. She later credited her more experienced sibling with helping her formulate strategies for the par-72, 6,364-yard course.

“She gave me a lot of tips, and said I shouldn’t be too aggressive here,” the younger Park said. “It helped me a lot with playing par-3s and par-5s. It’s important to keep your tee shots on the fairway here.”

Park began her Korean LPGA career in 2010 but remains winless so far. She said playing alongside LPGA players is “an honor.”

“I will try to enjoy myself watching these players over the next two rounds,” she said. “Being able to play an LPGA event is such a pleasant experience, and I think having that frame of mind helped me shoot a good round today.”

Lurking behind the co-leaders is the defending champion Suzann Pettersen of Norway. The world No. 2 shot a 3-under 69, with five birdies against two bogeys. She birdied three of the course’s four par-5 holes.

Six other players shot a 69, including former No. 1 Shin Ji-yai of South Korea and Korean-American star Michelle Wie.

Park In-bee, the world No. 1, is one shot back of Pettersen at 70. She started off with three birdies on the back nine but had back-to-back bogeys on the 12th and 13th. She picked up her final birdie of the day on the par-3 17th.

Park’s lead over Pettersen in the world rankings, money and Player of the Year points has dwindled in the second half of the season. Park has six wins this year but none since the final week of June. Two of Pettersen’s three victories this year came in September.

Lexi Thompson, who won the Sime Darby LPGA Malaysia last week, shot a 70, along with world No. 6 Choi Na-yeon, a two-time winner of this event, and reigning LPGA Rookie of the Year Ryu So-yeon.