Two-time defending champion Japan beat China 5-2 on Sunday to improve to 2-0 in Group A of the World Baseball Classic.
With Japan up 2-0 in the bottom of the fifth at Fukuoka Dome, Yoshio Itoi broke the game open with a bases-clearing double to center field that made it 5-0 for the hosts.
Japan starter Kenta Maeda picked up the win after striking out six and giving up one hit over five scoreless innings.
Cuba beat Brazil 5-2 earlier Sunday in its first game of the tournament. Brazil dropped to 0-2.
Two teams from the group will advance to the March 8-12 second round at Tokyo Dome with a chance to move on to the March 17-19 championship round in San Francisco.
Japan next faces Cuba on Wednesday.