WILLIAMSBURG — After hibernating in Cristie Kerr's garage for a while, a putter she used to crush the field in the 2010 LPGA Championship made a triumphant return Thursday in the first round of the Kingsmill Championship.

While Kerr got her 5-under par round in gear with a string of birdies on the back nine, So Yeo Ryu also used a strong effort with her putter on the back end of the River Course to post a score of 4-under. Kerr's 66 put her in second place, two shots behind leader Ariya Jutanugarn, while Ryu's 67 was good enough to have her tied for third place.

Prior to the start of the Kingsmill Championship, Kerr took to Twitter to announce her intentions regarding which putter she planned to use for the tournament — her Odyssey Marxman. With the putter in her bag for the '10 LPGA Championship, Kerr won the major tournament by 12 strokes.

No wonder she refers to the mallet as "sexy."

"I had a funny thing on Twitter that I was bringing sexy back," said Kerr, who switched back to the putter after recently using an Odyssey 2-ball putter.

"You've got to go with whatever works."

Kerr, who is 12th in the world rankings and who started her morning on the first tee while playing with Paula Creamer and Inbee Park, said she had used both putters over the years — switching from time-to-time when she felt she needed an alignment adjustment.

Kerr shot a 1-under 35 on the front nine, with birdies on the first and seventh holes, and a bogey on the fifth. On the back nine, she birdied the 11th, 14th, 17th and 18th holes on her way to a 31. It was an impressive performance for Kerr, who entered the tournament 56th on the tour in average putts per round (29.88).

"I never really tried a whole lot of new kinds of putters," said Kerr, who missed the cut last year at Kingsmill, but won the tournament in 2005 and '09.

"Sometimes you've got to change up your feel — or sometimes you can't aim."

Ryu, who is sixth in the world rankings, started on the 10th tee in a group with fellow South Koreans Jee Young Lee and Jeong Jang. Ryu took advantage of the more relenting, slower greens in the morning by carding birdies on the 14th, 15th, 16th and 18th holes.

At that point, she said she felt like she could've gotten to eight or nine-under, but she instead went on to log pars on holes one through nine.

Coming into the tournament, Ryu had earned a reputation this year as one of the better ball-strikers on tour, evidenced by the fact she was ninth on tour in greens in regulation (74 percent). As a member of the LPGA of Korea in 2011, she won the U.S. Open, and proceeded last year to win LPGA Tour rookie of the year honors.

With three top-five finishes this year, including a runner-up showing last month at the Kraft Nabisco Championship and a fourth-place effort last week in the North Texas LPGA Shootout, she's proving she's more than capable of building on her early success.

"I played with some guy at the pro-am (Wednesday), and he asked about the sophomore jinx, but I don't think so," said Ryu, who is making her first trip to Kingsmill. "Well, I played in the KLPGA Tour [LPGA of Korea] for four years. My sophomore year on the KLPGA was my best year on the KLPGA."

She was ninth on the LPGA Tour last year in average putts per round (29.25). Prior to Thursday's round, she was 45th this year in putts per round (29.79).

Friendly wagers on the practice green with a good friend have helped keep Ryu's putting game sharp. During the Kraft Nabisco Championship, she said Inbee Park, a fellow South Korean and the No. 1 ranked player in the world, often had gotten Ryu involved in putting games for $10 per hole on practice greens.

Though Ryu is no slouch with a putter in her grip, Park has a clear advantage in the putting category. She came into Kingsmill sixth on tour in average putts per round (28.57), after finishing first last year (28.34).

"She always said, 'Oh, you're the really great hitter and I'm a great putter,'" Ryu said. "So, we always (have) a little bit of an argument about how hard it (is) to make the putt, how hard it (is) to make the shot."