World Rugby were desperate to see a so-called Tier 2 nation in the quarter-finals and they have got one now. And who better than the hosts?
If wingers Kotaro Matsushima and Kenki Fukuoka ever have to buy a drink again in Tokyo there really is something wrong with the world. The pair scored three tries between them with Fukuoka getting two of them.
Those three scores, plus one from Keita Inagaki, took the wind out of the Scottish sails with 43 minutes gone before a belated Scottish comeback.
Scotland can have no complaints though, they were beaten by the better team, and can go home to lick their wounds, and they will have plenty of them.
Gregor Townsend's men were sniffing a draw, having been 28-7 down just after the break but at the death Japan turned the ball over and once it was booted into touch a crowd of 67,666 went gloriously bonkers.
Some of the Japanese offloading, particularly in the first half, would have had the world purring if it had been displayed by the All Blacks. But this lot can play and when the heat came on the Scots were not to up.
The tragic events of Saturday Typhoon Hagibis did its worst and claimed the lives of more than 15 people in the Tokyo area Japan were in need of a lift.
The nightmare scenario for the Brave Blossoms was the possibility that they would lose here and face elimination despite winning three of their pool matches.
That is what happened four years ago in England when, under the coaching of Eddie Jones, they were stymied by a defeat by Scotland at Kingsholm following a short turnaround after the miracle defeat of South Africa in Brighton.
The fans here were going bananas before the start of the game and by half-time with Japan leading 21-7 the noise was off the scale. After the saga of whether the game would played or not, as a result of the disruptive weather, it was good to see the Japanese get on the park.
They are light years ahead of the side that beat the Springboks in 2015 as head coach Jamie Joseph has made them tactically smart.
That win over South Africa was all about hanging in and being brave in the last few minutes, it might never happen again.
This and their win over Ireland were never in doubt. They were the better side on both occasions and might give the Boks a rattle in the quarter-finals.
Japan should certainly not be scared of going up against them. Here they were superb in denying Scotland the ball and had scored three tries by half-time.
After Finn Russell had scored for the Scots, to quieten the crowd slightly, Japan surged back into the match.
Wing Matsushima, who has a touch of Hollywood about him, made the most of a brilliant offload from Fukuoka to get over in the corner. Talk about a crowd pleaser.
Next up on 26 minutes it was the turn of prop Keita Inagaki to score a try that he will be boring the Front Row Union about for years to come.
In truth he did not have much work to do but he was in support of hooker Shota Horie and flanker Pieter Labuschagne before flopping over the line.
The Scots were bang up against it now and Japan did not relent. Just before the break Fukuoka made mincemeat of the Scottish defence and he was at it again just after the interval to secure his legendary status in these parts and get Japan the bonus point.
Then came the Scotland comeback. Prop WP Nel went over Jonny Gray's line break and Greg Laidlaw's snipe and on 55 minutes replacement front rower Zander Fagerson bulldozed over.
That was 28-21 and an invitation for Japan to show us what they have got. And they have got plenty even with the Scots fighting for their World Cup lives.
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