Wales head coach Matt Sherratt says he is more concerned by the prospect of a greasy match ball than the sweltering conditions facing his players in Japan.
The thermometer dial is expected to be around 30 degrees Celsius when Wales kick-off at 2pm local time in Kitakyushu on Saturday against Eddie Jones’ Brave Blossoms.
The temperature will feel a lot more when high humidity is factored in and the Wales squad, who used a heat chamber at home ahead of the two-Test series, have turned to ice baths, ice towels and cold flannel hats since arriving in Japan.
Wales are looking to end a horror run of 17 consecutive Test defeats in the Far East, but a victory is not guaranteed.
‘We've done everything we can to prepare the players for this,’ said interim head coach Sherratt, who has made 11 changes from the side hammered by England in the Six Nations Championship three months ago.
‘The players weren't hugely excited about the heat chamber in Cardiff, but they worked really hard.'
Blair Murray will be a key figure for Wales when they take on Eddie Jones' Japan on Saturday
Wales are without usual captain Jac Morgan in Japan as he is on British & Irish Lions duty
Former England head coach Jones is now in charge of Japan - his second stint with them
WALES TEAM TO FACE EDDIE JONES' JAPAN
Blair Murray; Tom Rogers, Johnny Williams, Ben Thomas, Josh Adams; Sam Costelow, Kieran Hardy; Nicky Smith, Dewi Lake (capt), Keiron Assiratti, Ben Carter, Teddy Williams, Alex Mann, Josh Macleod, Taulupe Faletau
Replacements: Liam Belcher, Gareth Thomas, Archie Griffin, James Ratti, Aaron Wainwright, Tommy Reffell, Rhodri Williams, Joe Roberts
Kick-off: 6am, Saturday
Venue: Kitakyushu
TV: BBC Wales
Sherratt added: 'It was as close as we could get in the UK to the temperatures in Japan, but it's obviously different here because we're training in it for 80 minutes rather than five or 10 minutes.
'We saw a lot of wet balls and we've trained in the middle of the day here to get used to the heat. If I'm honest it's not the heat, it's the ball (that's a problem).
‘It's very difficult to keep the ball dry. It's probably going to be a game on TV where the conditions look perfect, but the ball's going to be really greasy and will test your skill set.’
After being parachuted in to replace Warren Gatland midway through the Six Nations, Sherratt is again in charge of Wales in Japan this month while the Welsh Rugby Union continues to search for a new permanent head coach.
Wales are without usual captain Jac Morgan, who is with the British & Irish Lions in Australia. Absent too is scrum-half Tomos Williams who was also on Lions duty until he suffered a cruel hamstring injury.
There are four survivors from the record 68-14 defeat to England in March who will start in Japan – No 8 Taulupe Faletau, prop Nicky Smith, centre Ben Thomas and full-back Blair Murray remaining.
Faletau will win his 109th cap against Japan but the other two back-row members, Alex Mann and Josh Macleod, have only seven Test appearances between them.
Wales have lost their last 17 straight Tests - a run they're hoping to break against Japan
As well as Faletau, only wing Josh Adams, Smith and scrum-half Kieran Hardy possess over 20 caps in the starting line-up.
Hooker Dewi Lake captains the side, inexperienced pair Ben Carter and Teddy Williams form a second-row partnership and centre Johnny Williams returns after last featuring at the 2023 World Cup.
There is some experience on the bench in prop Gareth Thomas and back-rowers Aaron Wainwright and Tommy Reffell who are three of the six forward replacements.
Sherratt said: ‘We've had three weeks prep and it (selection) is a mixture of recent club form and trying to get some combinations we've seen in training.
'It's a new coaching group and we've tried to let the players start on an even playing field and select on what we've seen.
‘We feel conditions are probably going to be tough to start with and to have some real quality experience off the bench will be massive.
‘It's not really a 15 we've picked, it's a genuine 23.
'I've learned at Cardiff that you don't throw on all your experience at once because between 60 and 80 (minutes) is where some of the crucial decision-making comes in.
'We need a genuine 80-minute performance.’
The second Test will be played in Kobe on Saturday week.
Harlequins head coach Danny Wilson is a part of the Welsh back-room team working in Japan