Shin seizes share of lead at LPGA Seri Pak Championship
A round featuring five straight birdies from the third through the seventh holes propelled Shin to a nine-under-par total of 204, where she was joined by Lee after the American signed for a three-under-par 68 at Palos Verdes Golf Club in Los Angeles.
They were two strokes clear of Australian Gabriela Ruffels, Americans Nelly Korda and Malia Nam and China's defending champion Yin Ruoning.
Yin had the lead at 10-under through 15 holes before a triple-bogey seven at the 18th dropped her into the tie for third. Ruffels carded a 65, Korda a 67 and overnight leader Nam a one-over 72.
Shin, who added birdies at 15, 16 and 18, said the windy conditions made hitting into the small greens tricky, but once she got on her birdie run at the third things felt relatively "easy".
The former world number one, whose 11 LPGA titles include two British Women's Open crowns, plays largely in Asia nowadays.
But she took a sponsor's exemption to play in the tournament hosted for the first time this year by her childhood idol Pak Se-ri.
It's also a chance for the world number 18 to garner more world ranking points as she chases a Paris Olympics berth.
"It's quite big," Shin said of the possibility of playing in the Olympics. "That's why I asked Se-ri to want to play ... because I play the Japan Tour right now, they have points as well but much less than the LPGA Tour.
"You know, next year (will be) my 20th pro year," the 35-year-old noted. "But finally I find a new goal this year so since early January I went to Australia and did the hard work out. I went to Saudi, Singapore, Japan. I played all over the world because I'm very focused on my goal."
Yin falters late
Lee, who is chasing a first LPGA title, had six birdies in her three-under effort, chipping in for a birdie at the first before picking up another stroke at the second. She added birdies at the fifth, sixth and seventh and bounced back from bogeys at nine and 11 with a birdie at 16.
"I don't think I've ever played out here this windy," said the Southern Californian. "It is definitely really tough mentally as well to just stay in it."
Yin, who claimed her maiden victory at Palos Verdes last year and went on to win a major title at the Women's PGA Championship and reach number one in the world, looked in control despite the demanding conditions.
She holed out from a greenside bunker for a birdie at the 12th that put her alone atop the leaderboard at 10-under.
A three-putt from off the green at 14 dropped her back into a tie for the lead but she curled in a birdie putt at 15 to regain a one-shot advantage.
After pars at 16 and 17 she found the right rough off the tee at 18 and her attempt to thread a second shot under a tree ended with the ball hitting the tree and ricocheting further right.