Japan were dealt a hard lesson in how to play good, disciplined rugby Saturday as they went down 50-22 to Ireland in front of 27,381 at Ecopa Stadium.

Keith Earls' pace and skill, Dan Leavy's omnipresence and Paddy Jackson's boot and game control were simply too much for a very disappointing Brave Blossoms side, who missed tackles and were outplayed in every facet of the game by a team they will meet in Pool A at the 2019 Rugby World Cup.

Indiscipline once again cost Japan dearly, too, as they gave away penalties at key moments and had Heiichiro Ito sent to the sin bin in the 24th minute.

And the Irish took full advantage, scoring four tries in the first half -- three while Japan were down to 14 men -- and three in the second to give Japan coach Jamie Joseph plenty to ponder before the two teams meet next week in Tokyo.

"I thought it was the best week of preparation we had had," Joseph said. "But to beat one of the best teams in the world you have to execute well, apply yourselves and you need to be desperate. And we were not desperate enough."

On a warm summer's day, Japan were forced into a late change with Derek Carpenter replacing Timothy Lafaele at inside center and Ryohei Yamanaka coming onto the bench.

But they started reasonably well with Ryuji Noguchi -- Japan's standout player by a long way -- safe under the high ball and elusive, and the forwards generally holding their own.

"We started well, created pressure and put pressure on them at the line-out and with our kicking game," said Joseph. "But we weren't able to turn it into points."

And the visitors took full advantage, as they started to exert their authority on the game.

Jackson banged over a penalty in the sixth minute before the Irish pack destroyed the Japan scrum, allowing the Irish to claim a tighthead from which Earls sprinted over.

A Yu Tamura penalty in the 14th minute was reward for a little bit of Japan pressure, but that was as good as it got in the first 40 minutes.

Another elusive break from Earls saw Ireland deep in the Japan 22, and Japan down to 14 men with Ito shown a yellow card for repeated team infringements.

Rhys Ruddock's gamble of going for the corner rather than the easy three points paid off when Leavy went over rather too easily from the line-out and a further 14 points were quickly added with Earls putting away Leavy and Jack Conan to make it 31-3 at the break.

"On the back of our strong scrum we controlled a lot of the first half," said Ireland coach Joe Schmidt, whose detailed analysis and preparation was a major factor in his side stifling the Japan attack.

Conan capped an impressive performance by adding a second try shortly after the restart following a Japan handling error before Noguchi finally gave the crowd something to cheer about in the 59th minute, when he crossed for a well-deserved try following a good break from Kenki Fukuoka.

With both teams tiring in the heat, Garry Ringrose and Earls crossed for Ireland before Fukuoka and Yutaka Nagare gave a little bit of respectability to the scoreboard with late tries for the hosts.

"We saw how dangerous Japan are when given time and space on the ball. They were super in the last quarter of the game," said Schmidt.

Joseph, meanwhile, praised the younger players such as Noguchi and Fukuoka and the impact made off the bench by the likes of Nagare and Rikiya Matsuda.

"The plan wasn't working well and the players not desperate so something was wrong. So I changed the plan and the players."