Wales face the Brave Blossoms desperate to gain revenge for last weekend’s 24-19 reverse in Kitakyushu, in which they led 19-7 with 20 minutes remaining.
That was an 18th successive defeat and the tourists have insisted they are not using conditions as an excuse for results.
Captain Dewi Lake is unsure whether he wanted the roof open or closed.
“There is probably going to be a different type of heat being inside a closed stadium,” said Lake.
“I know in the Principality when the roof is closed, it gets sticky so with the heat over here I am not sure if that will be good or bad.
“I know there will be no sun and it will be in shade but sometimes the ball gets a bit wetter.
“We won’t make any excuses for the weather or surroundings, we will make sure we get our things right.”
Lake says he has not got used to the hot temperatures.
“The heat is tough but it’s the same for both teams,” said Lake.
“Last week we tried to find shade wherever possible and huddled in groups.If we were behind the posts or had just scored, groups were in shaded areas. So we tried our best to stay out the heat and sun as much as possible.
“I don’t think there is getting any used to it, it’s just about dealing with it.
“After two weeks we are probably better than we were at the start, and we will be fine at the weekend.”
