The 30-year-old from Okinawa dropped a shot on the opening hole after finding a bunker, but proceeded to collect five birdies at the fifth, sixth, eighth and 12th.
The three-time tournament winner on the LPGA of Japan ended the day a stroke clear of Mo Martin from the United States, with countrywomen Mina Harigae and Morgan Pressel and Australian Sarah Kemp a stroke further behind on two-under-par.
The diminutive Uehara, who enjoys karaoke, attributed her fine round to solid putting and said: "I had many good birdie chances but I couldn't make it. But this week, so good, so I have confidence right now."
Kemp, who finished tied for sixth in the ISPS HANDA Ladies European Masters on Sunday, was pleased with her solid 70. "I got into trouble a couple of times but I just tried to make a bogey and not make a really big number, so I think I did that well today," said the 28-year-old from Sydney, who had three bogeys against five birdies in her round.
On playing the course for the first time in this week's championship, she added: "I think it's one of the hardest golf courses I've ever played. We were lucky today with the weather. It wasn't as windy. But I played yesterday, a practice round yesterday, and it was pretty windy. It's quite tight and it's so intimidating off the tee. There's a lot of shots where you can't see the ball land and when you get up there, the fairway looks about ten yards wide, so it's definitely up there with the top five hardest golf courses I've ever played. But, one of the best golf courses I've ever played, too."
England's Holly Clyburn teed off the championship at 6.30am and ended the day placed as the best of the home contingent on one-under-par, alongside South Koreans So Yeon Ryu and Amy Yang and the World No.1 and defending champion, Stacy Lewis from the USA.
"I am, very happy, to go out there and shoot under par straight off is very nice," said Clyburn, 23, from Cleethorpes. "I started bogey, bogey, but it's not really bogey, bogey. I don't look at it like that. I gave myself a lot of opportunities and a lot of just shaving the hole, and after how I've putted the past few weeks, I'm very happy. I'm so much more confident over the ball and I'm happy to go out there and hole some putts."
Despite the moderately calm conditions, only nine players broke par on the first day, with the brutally thick rough claiming many casualties. The group of players on level par included past champions Karrie Webb and Jiyai Shin as well as the 17-year-old World No.2 Lydia Ko.
England's Charley Hull was one of 23 players to take a double bogey, or worse, on the first hole and the 18-year-old Solheim Cup star dropped another stroke on the second, but she recovered with three birdies against a closing bogey in a round of 73.
Hull, who had set her alarm at 4am for a 6.52am tee time, admitted to feeling a little extra pressure on the first tee owing to this being her home major championship, but said: "I just think because it's kind of a tight tee shot the first hole, but it's not that tight, but it's just, you know, first tee shot can be a little bit nervy."
Collated scores at the end of Round One:
68 - Ayako Uehara (JPN)
69 - Mo Martin (USA)
70 - Sarah Kemp (AUS) , Morgan Pressel (USA) , Mina Harigae (USA)
71 - Stacy Lewis (USA) , So Yeon Ryu (KOR) , Amy Yang (KOR) , Holly Clyburn (ENG)
72 - Emma Talley (USA) , Jiyai Shin (KOR) , Inbee Park (KOR) , Jessica Korda (USA) , Amelia Lewis (USA) , Lydia Ko (NZL) , Marina Alex (USA) , Suzann Pettersen (NOR) , Ai Miyazato (JPN) , Azahara Munoz (ESP) , Julieta Granada (PAR) , Karrie Webb (AUS) , Lexi Thompson (USA) , Anna Nordqvist (SWE)
73 - Meena Lee (KOR) , Charley Hull (ENG) , Gwladys Nocera (FRA) , Dori Carter (USA) , Jeong Jang (KOR) , Pornanong Phatlum (THA) , Jenny Shin (KOR) , Chella Choi (KOR) , Brittany Lang (USA) , Shanshan Feng (CHN) , Erina Hara (JPN) , Georgia Hall (ENG)
74 - Angela Stanford (USA) , Xi Yu Lin (CHN) , Catriona Matthew (SCO) , Stacey Keating (AUS) , Eun Hee Ji (KOR) , Alison Walshe (USA) , Kristy Mcpherson (USA) , Alena Sharp (CAN) , Carlota Ciganda (ESP) , Beatriz Recari (ESP) , Linda Wessberg (SWE)