Takeshi Okada's side take on fierce rivals South Korea on Monday in a tough send-off game which even the head of Japan's FA believes is a risk.
"The players wouldn't call it risky," midfielder Makoto Hasebe told Reuters on Sunday. "For us it's a big chance. If we beat Korea it would give us a real confidence boost for the World Cup. We're all up for this game."
Despite a hugely ambitious World Cup target set by Okada, Japan have spent most of their final domestic camp going over the finer points of defending.
"South Korea and the other teams at the World Cup are definitely a step up in level," said Hasebe. "For the past three days we have been talking about covering and risk management."
The Koreans have notched up 33 wins to Japan's 10 in their previous 61 meetings and their last victory at the East Asian championship earlier this year almost cost Okada his job.
With both teams heading for South Africa, a rare opportunity to field their strongest sides against each other means Japan have more to lose in Saitama.
"We're not that nervous," said Hasebe, who will be returning to the home of former club Urawa Reds for Monday's game.
"It's Japan's best team and Korea's best team so we'll see who's the best," added the Wolfsburg player. "There's still three weeks before the World Cup. We have to peak at the right time."
Japan face Cameroon, the Netherlands and Denmark in Group E at the World Cup after completing their preparations with matches against England and Ivory Coast.
"We don't have the luxury of being able to tweak, tweak, tweak things," said Hasebe. "We just have to win our warm-up games and boost people's expectations of us."
