The holders Japan overwhelmed Olympic champions South Korea 14-2 to become the first team to reach the second round of the World Baseball Classic.
Ichiro Suzuki broke out of his recent slump while Shuichi Murata and Kenji Johjima smashed home runs before the game was ended on the mercy rule after seven innings at Tokyo Dome.
The Koreans should still comfortably beat China to advance along with Japan while securing a shot at instant revenge over their fierce rivals in Monday's final Pool A game.
Earlier China knocked Taiwan out of the World Baseball Classic with a 4-1 win, dealing another major blow to the island's sporting pride.
