Yuki Soma (25), Shuto Machino (22) and Takuma Nishimura (25) each scored twice to kick-start Japan's challenge in the biennial regional competition, which also features China and South Korea.

Coach Hajime Moriyasu picked a side made up exclusively of Japan-based players, with defenders Miki Yamane and Shogo Taniguchi the only members of the starting lineup to have featured in the final phase of Asia's World Cup preliminaries.

Nagoya Grampus winger Soma gave the hosts the perfect start when he curled in a right-foot free kick from 25 metres that caught out Hong Kong's slow-moving goalkeeper Paulo Cesar.

Machino doubled Japan's lead in the 20th minute with a bullet header following Yamane's cross from the right and Moriyasu's side extended their advantage two minutes later as Nishimura bent his low shot into the bottom corner.

Nishimura hit his second five minutes before the interval when he stepped forward unopposed to beat Cesar from distance.

Soma netted again 10 minutes after the restart with a clever flick after Yamane hit a low cross into the six-yard box and two minutes later Japan had a sixth as Machino pounced when Cesar let the ball slip out of his grasp.

Japan will be appearing at a seventh consecutive World Cup finals in November in Qatar and Moriyasu's side have been drawn to face Spain, Germany and Costa Rica.

The East Asian Championship will continue on Wednesday when three-time defending champions South Korea meet China in Toyota.

China had been due to host the tournament but relinquished their rights due to the Chinese government's ongoing attempts to enforce a zero-COVID policy nationwide.