The big Japanese win included Takashi Usami's hat trick and a goal by captain Musaka. After two executive victories, Japan was the first team to win a ticket to the quarter-finals.
In another match in group C, the United Arab Emirates (UAE) were held to a goalless draw by Jordan.
As a result, Japan currently tops group C with six points, followed by Vietnam with three points. The UAE and Jordan both have one point. Vietnam will meet defending champions UAE in the next match and they will need at least one more point to reach the quarter-finals.
