American Chan Kim rode on a strong front-nine display on his way to firing an eight-under-par 64 to lead the opening day of the Casio World Open in Kochi.
Starting from the 10th tee, the 32-year-old carded an incredible 30 on the opening nine holes at the Kochi Kuroshio Country Club, thanks to birdies on 10, 12, 13, 16 and 17, and an eagle on the par-five 18th.
Kim's sole blemish was on the par-four 15th.
After the turn, Kim held steady to pick up two more shots on the five and nine to give him a two-shot advantage over Aguri Iwasaki.
A large group at five-under are in a tie for third including a strong international contingent featuring Justin De Los Santos of the Philippines, Thailand's Thanyakon Khrongpha, American Jay Choi and South Korean trio Jung-gon Hwang, Young-han Song and Dong-kyu Jang.
Kazuki Higa, who won his fourth JGTO title last week to edge closer to the Money Rankings throne, battled to a 72 to be tied for 71st.
Kim has attributed his fine first-round effort to the front-nine brilliance.
"I was able to play confident golf all day thanks to the strong momentum of the front-nine where I shot six-under," said Kim, who's currently ranked 20th on the money list.
"I was putting it very well. The highlight was definitely the lengthy putt for eagle on the 18th.
"It would be great if I could play golf the same way I did today for the remaining three days. I look forward to hitting five-under every day.
"If there's one area to fix, I would like to improve the accuracy of iron shots and approach shots. I need to do better on the par-five too by trying to get to the green in two."
The tournament his week is the penultimate leg of the season.
The top 30 money leaders after this week will advance to the next week's season-ending Golf Nippon JT Cup.
Leading first-round scores:
(Japan unless stated)
64 - Chan Kim (US);
66 - Aguri Iwasaki
67 - Kaito Sato (am), Mitsumasa Tamura, Konosuke Nakazato, Keita Nakajima, Jung-gon Hwang (Kor), Rikuya Hoshino, Yuwa Kosaihira, Jay Choi (US), Young-han Song (Kor), Ryutaro Nagano, Satoshi Kodaira, Thanyakon Khrongpha (Tha), Dong-kyu Jang (Kor), Justin De Los Santos.