Mito Pereira of Chile led the way as the PGA Tour quartet made their presence felt by placing themselves in the top 12 on the opening day of the Dunlop Phoenix Tournament in Miyazaki.
It was the 27-year-old Pereira who impressed the most when he carded a six-under-par 65 to tie for the lead with Taihei Sato at the Phoenix Country Club on Thursday.
Pereira, who hogged the limelight earlier this year with a joint third spot at the US PGA Championship, sank seven birdies against a bogey as Sato matched it with a bogey-free round containing six birdies.
The pair led by one shot from Rikuya Hoshino and Aguri Iwasaki, who were tied for second.
Canada's Corey Conners also got off to a bright start when he shot a solid 67 to be tied fourth with his PGA Tour counterparts American Aaron Wise and South Korea's Tom Kim sitting a further shot back in joint 10th.
Defending champion Chan Kim opened his title defence bid on an encouraging note but not after he overturned a difficult start to return a 68 to be part of the cluster of 15 players in 10th place which also included Philippines' Juvic Pagunsan.
Starting from the 10th, Pereira enjoyed a run of three straight birdies from the 13th before conceding a bogey on the par-three 17th to be out in 33.
But that turned out to be his only blemish of the day as he picked up four more shots on the second, fourth, seventh and ninth to mark a memorable maiden JGTO round.
"I was able to play consistent golf all day long. Both tee shots and putts steady from start until the end," said Pereira, who finished tied fourth at the Tokyo Olympics last year.
"Being able to start well in Japan gives me lots of confidence."
Conners, 30, has certainly enjoyed himself on a "stress-free" Thursday.
"It was a very solid and stress-free round, I drove the ball well, didn't make any mistakes and kept things really simple," said Conners, whose last visit to Japan three years ago saw him finish joint sixth at the ZOZO Championship.
"I'm pretty happy with everything although I didn't make as many putts as I would like to.
"Having said that, I felt like I rolled the ball very well as a number of my putts had good chances to go in.
"If I can continue hitting solid putts, eventually more of them will go in."
World number 15 Tom Kim, 20, lived up to his billing as the highest-ranked golfer in the field with a flawless card marked with three birdies, including on the 18th.
"I played great, I hit a lot of quality shots but missed a few putts," said Tom, who took the world by storm last by matching Tiger Woods' feat of reaching two wins on PGA Tour at 20.
"Obviously with the (placing of) pin position, there's no easy putt out there. I hung in there and it's always nice to finish off with a birdie."
Chan Kim, seeking his eighth JGTO crown, had to battle from three-over after five holes to finish with a credible three-under after responding brilliantly with six birdies.
The 32-year-old said his fitness was getting better after enduring a hectic schedule where he played six tournaments in a row including a trip back to US for the Korn Ferry Tour.
"After going three over through five holes, I thought it would be good for me to finish even par. So to finish three-under, I'm really happy," said Chan.
"I was feeling okay today. I wasn't too tired as I got a good sleep last night. I'm hitting it well just the driver had a couple of misses. My putting is starting to get better.
"With the scores being low today, I have to play really well to have a chance to win."
Leading first round scores
(Japan unless stated)
67 - Mito Pereira (Chi), Taihei Sato;
66 - Rikuya Hoshino, Aguri Iwasaki;
67 - Corey Conners (Can), Shugo Imahira, Taisei Shimizu, Ryosuke Kinoshita, Ryuichi Oiwa, Kaito Onishi, Takahiro Hataji