A penalty from Chelsea's Lewis Baker took England under-21s through to the final of the Toulon Tournament for the first time in 22 years where they'll play France.
Baker scored his third in as many games in this tournaments and Japan couldn't respond, despite coming close in the second half as a shot struck the crossbar. England's win was deserved with that crossbar effort Japan's only real chance to level things. John Swift earned the penalty for Baker, drawing a foul as he cut inside from the right flank, Mitsumaru tripping him.
England had beaten Paraguay, Guinea and Portugal in an unbeaten run to the final.
England head to first Toulon final in 22 years
England, as expected, dominated early proceedings. With control of the ball, Japan were left chasing and England's opening chance came through Grimes and Stephens but the cross from the wing was weak and Cauley Woodrow had little chance of reaching it before the Japanese defence dealt with it.
Baker's penalty strike came moments later thanks to Swift's movement on the right. Baker scored his third goal in three games to put England in a 15th-minute lead.
Ahead of the goal, there had been little urgency in either attack. Gareth Southgate's Young Lions knew it would require an extreme goal difference swing elsewhere to see them miss out on the final and that could be seen.
Ado Onaiwu had Japan's first effort but they looked particularly unthreatening and England, although earning multiple free-kicks around the Japanese penalty area, looked in a similar position. Angus Gunn matched Onaiwu's shot with the save. The chances came more quickly after that first one from Makoto Teguramori's side. Notsuda shot from the edge of Gunn's penalty area but it flew past the post without danger. Minamino had another long-range effort after Calum Chambers let him past far too easily. That shot swerved over the crossbar.
England far from perfect but comfortably finish victors
Baker, the only goalscorer, responded with a long-range effort of his own from 30 yards. He hit on target, unlike the Japanese, but the goalkeeper dealt with it comfortably. After half-time, the Chelsea midfielder was replaced by his teammate at Stamford Bridge, Ruben Loftus-Cheek, and Matthew Targett came off for Dominic Iorfa.
Like in the first half it was timid from both sides. England's intensity was low, knowing their place in the final was almost certain. Grealish, the star man in the team, had been quiet in the opening forty minutes (one half in this level of football), but he combined well with the more lively John Swift to win a free-kick. The latter watched his effort squeeze past Nakamura's right-post but it was better than first half efforts from his teammates.
Japan had a free-kick themselves that resulted in a corner as Angus Gunn saved at his back post. The action came to life after a mild beginning to the second half with Notsuda striking the crossbar, but beating Angus Gunn. It came back to the midfielder nicely but his strike on the volley was excellent and he was unlucky to see his cannon off the bar.
Moments later, the crossbar at the opposite end was shaking too. Kasey Palmer was fouled after a great run and Grimes took the resulting free-kick. With superb swerve on the ball it had beaten Nakaruma but, again, hit the bar.
As in the first half, Japan looked unable to penetrate the English defence, instead opting for long shots that wasted their possession. Ideguchi saw his shot go well wide of Gunn's wide post from 30 yards.
England go into final unbeaten
With ten minutes remaining, England were already attempting to see out the game and move into t the corner, particularly Jack Grealish. Japan had a late chance with a free-kick and a corner but wasted both opportunities.
It wasn't perfect for Southgate's side, certainly not, but they go into the final against France unbeaten.