"Wha, wha, what?" was the reaction of most Japanese rugby fans who woke up on Sunday morning to the news that their team had defeated South Africa.
The Japanese were aiming for a win in the game with Scotland - they thought that they had no chance with South Africa.
Hence there was no live televised coverage in Japan for this game and many fans did not even bother to cheer the team on.
Disbelief is the only way to sum up the reaction to the result. Japanese rugby fans were at as much of a loss as the South African players on the pitch when the final whistle blew.
Japan had always put up a good fight, but that was it - it had never pulled off an upset as big as this.
So what led to this result? Japanese rugby has changed dramatically over the years, introducing many elements from abroad, not only in terms of foreign players, but also in ideas and styles of coaching and playing. We were rather late in catching up with the internationalised rugby scene, where national borders count for little.
Thanks to this the overall capability of the players has gone up dramatically.
In Japan, rugby is not as big as baseball and football, which are professionalised sports. Japanese rugby is semi-professionalised, but still with a very strong emphasis on amateurism.
Hence rugby is mainly played as a sport of honour, and not for money. We have a strong solid group of fans (myself included) who love and support this approach to the sport.
During winter, it becomes one of the country's biggest sports. It mainly takes the form of school championships and corporate championships and club teams are not big in Japan.
Hence for many the school or firm comes first, their own fame second. This is another reason why it attracts so many viewers as the purity of the game is very attractive.
In Japan, rugby is considered as a true team sport. "All for one, one for all" is the typical attitude towards the sport here.
Also, the Japanese tend to have a strong tendency to collectivism. It is unlikely you would be able to create an individual hero, as happens in US sports.
Also, knowing rugby, a winger's try could have come from the unnoticed efforts of a prop who robbed the ball in a maul.
Some news sources are hailing Ayumu Goromaru (full-back and vice-captain) as a hero as he won 24 of Japan's 34 points - but of course we too have those that take a more American view of the sport.
At the end of the day, we praise the collective effort of the team, and the people surrounding and supporting it. That is very much the Japanese way.
And it has yielded a big bonus after 24 years of not having a single win in the World Cup.
This victory will undoubtedly give a strong boost to coverage and attention for the next World Cup in 2019, which is to be hosted in Japan.
Japan can now move forward to a new era, where we are not just nice guys who put up a good fight. This year, the cherry blossom - engraved on the jerseys of the Japanese team - blossomed fully in September in Brighton.
Seijiro Takeshita is professor of Management and Information at the University of Shizuoka and former captain of the London Japanese Rugby Football Club.