Ireland head into their crucial Pool A clash against Samoa on Saturday with serious concerns over the state of the pitch in Fukuoka. Players were seen lifting strips of turf off the ground during Friday's captain's run.
World Rugby, in conjunction with the tournament's organising committee, took the decision to re-lay the pitch at Hakatanomori Stadium following France's match against the United States on October 2.
However, it appears the new turf has not yet bedded in. Chris Farrell was filmed placing a rugby ball under one of the strips of grass at one point during training.
Given the ongoing controversy over Typhoon Hagibis, the last thing World Rugby needs now is players injuring themselves due to a pitch cutting up badly. And Ireland were in conciliatory mood in their press conference, with assistant coach Greg Feek saying he "did not want to cause any more controversy at this stage". But Joe Schmidt, Ireland's head coach, looked far from happy during the publicly accessible part of training.
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Asked for his reaction, scrum coach Feek said: "Well, I mean, you guys are pretty smart individuals, you would have seen the pitch yourselves. We know they had to relay the pitch. We went out there and just had an inspection and we have been given all the assurances by World Rugby that it's safe to play on and that's all we can ask for.
"Obviously I don't want to predict anything or cause any more controversy at this stage. We will just try to back the players, trust that the pitch will do its job."
Wing Keith Earls admitted that it did "not look great" but said it did not actually feel too bad to run on.
"It's flat and it's quite firm," he said. "Like what Feeky said, it has been inspected and it has been deemed playable. That's the way it felt out there today. I suppose it's going to be the same for both teams. We just have to get on with the job."
The concern from Ireland's point of view is not just getting the win, but avoiding injuries, with a potential quarter-final against either the All Blacks or South Africa coming up next weekend.
Feek said scrums would be an area of particular concern. "As Earlsy said, it's fine running around out there - passing, kicking, jumping, tackling and all the rest of that stuff - but when it comes to a static, isometric position like that, where there are impacts going on, you're always going to be a little cautious.
"We're going to try to make sure the scrum stays up, not just for safety but for the game itself."
In a statement, World Rugby said they were "confident in the integrity" of the Hakatanomori pitch. "The tournament has dedicated nurseries where back-up turf is meticulously prepared in line with Rugby World Cup standards," the statement read. "While the look of the turf may not be perfect, as would be expected with a very recent installation, we are confident that the pitch will perform superbly."
Ireland have brought Johnny Sexton back at 10 as they look to win with a bonus point to guarantee themselves a quarter-final. If Ireland win without a bonus point, or lose the game, their fate will be determined by the outcome of Sunday's Japan-Scotland game.
Samoa head coach Steve Jackson said it would rank alongside the country's famous victory over Wales at Cardiff Arms Park in 1991 if they could cause an upset.
"Now, being in the professional era, this is probably one of the biggest games that we could play and win," he said. "To be ranked where we are and they are in the top five in the world, for us it would be massive.
"Knowing that we're on an airplane on Monday, going home, to have a scalp like that would be great."
Jackson predicted an open contest, with Ireland chasing a bonus point. "We are not going to win this game by kicking penalty goals," he said. "It's going to be done by teams scoring tries and teams chancing their arm because I know that the other team is not just going to look to secure the win.
"They need to make sure that they have got the bonus point in the bag and they are sitting in the quarter-finals and not worrying about what is going to happen the next day.
"Likewise, we are not there to just make up the numbers. We are going to throw everything at it as well and make it as spectacle. Hopefully we come out on the right side of the ledger."