The Kiwi finished her third round today in a share of third after shooting a five-under 66 to steadily climb the leaderboard at the Kasumigaseki Country Club.
That left Ko at 10-under for the tournament, five shots off leader Nelly Korda and two behind second-placed Aditi Ashok.
Ko is currently level with three other players in the bronze-medal position but might not get the chance to separate herself in the final round as an impending storm is threatening to cut short the tournament.
That would see the 54-hole totals determine the podium and leave Ko waiting for a potential playoff in her quest for a second Olympic medal. She won silver in Rio in 2016.
"Overall I played really solid today and gave myself good opportunities, and that's what you've got to do. I tried to stay cool, which is also a very important part of just being out there," Ko told Sky Sport after her round.
"I played really solid yesterday as well - I was disappointed with the way I finished [with back-to-back bogeys] that round and I was hoping that wasn't going to feed into the way I approached today. Especially not knowing how many holes we're going to play.
"With the position I've put myself in today, I really hope that I get a chance to go for it tomorrow. But with golf, you never know. I could end up falling further behind or I could be standing on the podium. Hopefully, the weather god is nice. I saw the forecast was a little better than what it looked like a couple of days ago so fingers crossed."
Round four has been rescheduled to start an hour earlier than normal on Saturday (at 9.30am, NZT) and all daylight hours will be used in a quest to fit in a fourth round, with organisers also leaving open the possibility of play on Sunday.
The way Ko has improved throughout the tournament, it would be understandable for the Kiwi to pray to the weather gods to allow another 18 holes for a final-day charge.
Ko shot the best round of the field on the third day, moving up from a share of ninth at the halfway point.
