The 22-year-old, the daughter of Czech tennis legend Petr Korda, the 1998 Australian Open champion, has shown remarkable consistency for the 36 holes at the sun-baked Mission Hills Country Club to reach 11-under 133.
Her nearest challenger is South Korea’s Mirim Lee, who carded a superb seven-under 65, while 2014 champion Lexi Thompson is also looming large after a 67 to be four shots back with Denmark’s Nanna Madsen.
Korda relied on steady play from tee to green and a “hot” putter, making crucial par saves from 20 feet at the par-5 second and 25 feet at the par-4 third.
“Definitely very happy with my putting today, and I was superbly happy with bogey-free,” said Korda, one of the rising young stars on the LPGA Tour.
Five birdies from Korda kept Lee, who birdied three of the final five holes, at bay while another South Korean, Chun In-gee, fell back after a one-under 71 to be five back alongside Kelly Tan of Malaysia.
American Danielle Kang, who can top the world rankings with victory at Mission Hills, has ground to make up after a 71 left her six shots off the lead.
Her compatriot Thompson is better placed, with her power game suited to the course as three birdies in four holes at the start of the round left her firmly in the mix ahead of the weekend.
All the players face a grueling two rounds with the current heatwave in California expected to produce temperatures in excess of 100 degrees fahrenheit (37 celsius) on Saturday and Sunday.
The coronavirus pandemic saw the tournament, originally scheduled for April, moved to its September date, but there are absentees.
Most notable is world number one and defending ANA champion Jin Young Ko, who decided not to travel from South Korea to play because of Covid-19 concerns.
Also missing is this year’s first major winner, Sophia Popov, who stunned the golfing world by claiming the British Women’s Open last month as a rank outsider.
Her previous low ranking didn’t qualify her for an invite to the ANA, while the five-year exemption the German gained for her victory at Royal Troon does not start until next spring.
World number three Korda, whose sister Jessica is also a leading player on the LPGA Tour, will be hoping to continue her fine form to take the next step as a major winner, with her previous best third in the 2019 Women’s PGA Championship.
Averaging just 1.5 putts per hole in the tournament, her touch on the lightning fast Mission Hills greens could prove crucial.
“Golf is just all about momentum, so you roll one in here and there and it just makes it a lot easier,” she told reporters after her second round.