Denmark's Nicolai Hojgaard outscored his twin Rasmus by four shots to sit one off the lead at the Baycurrent Classic in Yokohama.
Nicolai, a Ryder Cup winner in Rome, missed the cut at last week’s Sanderson Farms Championship but carded four birdies on his front nine and two more at the 16th – where he chipped in from 94 feet – and 17th with his only blemish a double-bogey six at the 11th.
His three-under 68 put him in a large group, which included Australian Adam Scott, one shot behind Americans Max Greyserman, Bud Cauley and Brian Campbell on a day of strong winds as a result of Typhoon Halong.
Rasmus, having finished joint third last week immediately off the back of his own Ryder Cup win in New York, opened with two double bogeys and a birdie in his first four holes on his way to a one-over 71.
United States Ryder Cup duo Xander Schauffele and Collin Morikawa both shot level-par rounds.
There are no Irish players in action in Japan this week.