Kim, the 1999 Rolex Rookie of the Year, birdied eight of her first 12 holes at The Club at The Strand en route to an eight-birdie, no-bogey 64. At 8-under-par, Kim is one shot clear of Wendy Doolan, who opened in 65.
Kelli Kuehne and Eva Dahllof share third place at 6-under-par.
The diminutive Kim (5'1') is accustomed to being near the lead. She recorded 13 top-10 finishes a year ago, and began this season with a tie for 10th at the YourLife Vitamins LPGA Classic in Orlando - coincidentally won by friend and fellow South Korean Se Ri Pak.
In just two seasons on Tour, the 24-year-old Kim has captured three titles and missed only five cuts. Thursday, she began her run for victory No. 4 with a 6-under-par 30 on the front nine.
Crisp iron-play and a steady putter highlighted Kim's outward half. With a new flatstick in her bag, Kim made three birdie putts of 12 feet or more.
'I switched to Never Compromise because last week I switched to Odyssey and I didn't make any short putts,' said Kim, who also recently altered her putting grip. 'Today I used the cross-handed putting all day out there because it felt good from the beginning and then all the way through.'
Upon making the turn, Kim, nicknamed Peanut because of her physical stature, continued her stellar play by birdying the 11th and 12th holes, both of which are par-fives. She then carded six consecutive pars to close her round.
Doolan is coming off an injury-plagued 2000 season in which she made 16 cuts in 19 starts. Her year included a career-best, runner-up finish at the Wegmens Rochester International.
Beginning on the back nine, the 32-year-old Australian birdied the 11th, 12th, 13th, 14th, 15th and 17th holes. In that stretch, she was forced to only convert one birdie putt of more than 10 feet.
Her lone blemish on the day came at the par-4 4th, her 13th hole. However, that bogey was sandwiched between a pair of birdies at the third and fifth holes.
'Every time you card a low number it feels different,' Doolan said after tying her career-low round on the LPGA. 'I played really well and I was aggressive out there on the back nine and then made the turn and stayed aggressive on the front nine.'
Thirty players are within four shots of Kim's lead, including Hall of Famer Betsy King. Coming off a two-win 2000, King recorded her first round in the 60s this season, a 5-under-par 67. The 33-time LPGA winner is tied for fifth place with Brandi Burton, Helen Dobson, Cathy Gerring, Heather Bowie, Dawn Coe-Jones, Jean Bartholomew, Vicki Goetze-Ackerman and Laura Diaz (formerly Philo).
The biggest names in the field are bunched up at 4-under-par. Karrie Webb, Meg Mallon, Grace Park, Kelly Robbins, Beth Daniel, Dottie Pepper, Pat Hurst and Sophie Gustafson all opened in 68.
Defending champion Nancy Scranton is in a 20-way tie for 31st place after carding a 3-under-par 69.