Shampoo, baby oil and water may be disappearing in industrial quantities from team hotels and local pharmacies having been identified as essential items to create ‘slippery ball syndrome’, the knock-on effect of the humidity in Japan.

Teams including Ireland’s opponents, Scotland, who Joe Schmidt’s side meet in their opening Rugby World Cup Pool A match on Sunday, had trained with rugby balls dipped in a variety of liquids - in the Scots’ case it’s shampoo - that will mimic the challenging handling conditions that teams will face due to the humidity.

The weather forecast for Sunday is thunderstorms. The Scots have been practising with balls soaked in shampoo to condition their players against the perils of a wet ball. Based in Nagasaki, temperatures have reached 33 degrees with humidity levels of almost 75 per cent.

Wales’ lubrication of choice is baby oil, splashing it on rugby balls in training. Head coach Warren Gatland explained: “We’ve been using wet balls and been using baby oil on them as well.

“We’ve taped them up as well and we’ve already been through that process in the camps we had before we’ve been away. We have been to two camps where one was at altitude and it was very hot in Switzerland, and then it was the late 30s in Turkey.

“We’ve done as much as we possibly can in terms of dealing with the heat. I think the humidity is going to be a factor . . . it’s how we cope with that.”

Late kickoffs on hot days will mean that players must deal with high humidity and a slippery ball.

“Players who have been to New Zealand will have experienced that. I come from Hamilton, it’s incredibly humid there. We know what it’s like and have players who have experienced a lot of night rugby so we feel we’ve prepared well.”

England have also been preparing for slippery balls at their team base in the southern city of Miyazaki. England’s hooker Jamie George explained: “We have buckets (of water) on the side of the pitch and we put the ball in that before we throw it. We are the lucky ones because we get a towel before we throw, so we’re at least allowed to dab it down a bit. We saw it in training yesterday that the ball is slippery.”