Hurley just four off the pace after opening 67 in Japan
West Waterford's Gary Hurley birdied three of his last seven holes to keep the leaders in his sights in the ISPS HANDA – CHAMPIONSHIP.
The former Walker Cup star (30) followed a birdie at the sixth with a bogey at the 11th before picking up further shots at the 12th, 14th and 18th.
His three-under 67 left him tied 31st at PGM Ishioka Golf Club in Omitama, just four shots behind England's Andy Sullivan and South Korea's Kim Yeongsu, who opened with 63s to lead by a shot from Swede Alexander Björk, Canada's Aaron Cockerill and South African Deon Germishuys.
Tom McKibbin is tied for 100th on one-over after making just one birdie in a 71, while disability golfer Brendan Lawlor, the world number two, struggled to an 81 to prop up the field.
Four-time DP World Tour winner Sullivan fired eight birdies in his 63 alongside Lawlor and Romain Langasque as Kim produced a bogey-free, seven-birdie round to join him in the lead as the DP World Tour hosts its first regular season event in Japan alongside the Japan Golf Tour Organisation.
Englishman Sullivan started from the tenth tee and made birdies at the 12th, 15th, 16th and 18th to reach the turn in 31.
He then reeled off a hat-trick of birdies from the third before recovering from a bogey on the seventh with a closing gain from around eight feet.
"Really pleased, just got off to a good start," Sullivan said. "A lot of right flags out there for me to find - as my playing partner Romain Langasque told me, 'Every flag out there is a right flag and you fade the ball, so it's perfect for you today.'
"It was good fun playing with Brendan (Lawlor) and Romain, very relaxed vibe.
"Me and my coach have been working on going back to when I was playing my best, around 2015, 16, so we've looked at swings from there and almost tried to mimic that.
"It's getting close, feel confident with the irons. Driver is still taking a bit of work. On the whole, the game is feeling good. It feels a lot more under control again, less of the erratic shots."
Kim picked up his first birdie of the day at the fourth before catching fire around the turn as he reeled off six birdies in eight holes from the ninth for a share of the lead.
"I feel good because I didn't make any bogeys today," Kim said. "I played in a tournament in Japan in 2012, so this is the first time in about 10 years.
"I played comfortably, looking at a nice view of a good golf course. Playing in front of many spectators was fun, even in the first round.
"My shots were not in good shape at the beginning. However, it seems I putted well, so that helped today's score. I hope it goes well tomorrow. I will be able to play with less stress because I played well today."
ENDS