Japan head coach Eddie Jones said "inexperience can sometimes be a blessing" as he named a young team on Thursday to face struggling Wales in the first of two home tests.
Jones selected two uncapped players to start against the Welsh in southwestern Kitakyushu on Saturday, with another six on the bench.
Wales have lost their last 17 tests – a record for a Tier One country in the professional era – and Jones wants his young side to take advantage of the hot and humid conditions.
"Inexperience can sometimes be a blessing, particularly in hot conditions," the former Australia and England boss said ahead of the game, where temperatures are expected to reach 32 Celsius.
"If they get out and really play with a lot of energy, a lot of determination, it will be up to the experienced players to steer the ship."
Among Japan's new caps will be the diminutive 1.67 metre tall (5ft 5in) wing Kippei Ishida, who Jones said "can be a Japanese version" of South Africa livewire Cheslin Kolbe.
"He's similar size, got great feet, great aerial skills, and in training he's impressed everyone," Jones said of Ishida, who will start on the right wing.
"It was impossible not to select him."
Veteran loose forward Michael Leitch captains the team for his 88th cap, with Japan regulars Warner Dearns, Dylan Riley and Seungsin Lee also in the starting line-up.
Jones has had his players in a training camp close to Kitakyushu for the past three weeks and he said they were "ready to go".
"It's been 32 degrees every time we've trained, the ball's like a cake of soap, we've wet the field, so it makes the conditions difficult for the players," he said.
"We can't do more heat acclimatisation than we've done."
Japan will host Wales in Kobe for the second test on July 12.
Japan (15-1):
Takuro Matsunaga; Kippei Ishida, Dylan Riley, Shogo Nakano, Malo Tuitama; Seungsin Lee, Shinobu Fujiwara; Amato Fakatava, Jack Cornelsen, Michael Leitch (capt); Warner Dearns, Epineri Uluiviti; Shuhei Takeuchi, Mamoru Harada, Yota Kamimori.
Replacements: Hayate Era, Sena Kimura, Keijiro Tamefusa, Waisake Raratubua, Ben Gunter, Shuntaro Kitamura, Ichigo Nakakusa, Halatoa Vailea.