To start with, it is a team that was well prepared for this tournament, a point the Japan coach, Jamie Joseph, emphasized after the Ireland match.

He said Japan had been preparing for the game much longer than the Irish have, “the last year at least, if not the last three years.” He added, “The Irish have been thinking about this game since Monday.”

And the Japanese aren’t likely to get too far ahead of themselves. They play a winless but talented Samoa team next, on Saturday, and despite the Samoans’ 34-0 shellacking at the hands of Scotland, Joseph will not take them lightly. Samoa was heavily penalized and not happy about it. One player was sent from the field twice with yellow cards, the second one bringing a red-card dismissal. The Samoans will be highly motivated, but will have their hands full.

The Japan team is confident, almost to the point of being cocky, a trait its veteran captain, Michael Leitch, embraces. He told Reuters before the tournament that the team’s goal isn’t, as widely reported, just to make it out of the pool stage and into the quarterfinals, or to be considered a Tier 1 rugby nation.

“I think you need to be very brave in what you say; we want to make the quarterfinals, but ideally, we want to win the World Cup,” Leitch said.

“That is an outrageous statement, but it changes your whole behavior: If you want to make the quarterfinals compared to if you want to win the World Cup, it changes your behavior. So I guess we are going to have to try to win the World Cup and see how far we can get.”

To do that, of course, Japan does need to advance out of Pool A. Four years ago, it became the first team to win three pool stage matches and not advance, despite its historic 34-32 upset of South Africa, a match that everyone here in Japan is thinking about. But to this bunch of players, South Africa is ancient history.