Props John Schwalger and John Afoa come into the front row with Anthony Boric starting at lock, while Jamie Nutbrown and Stephen Donald are the new inside back pairing alongside a midfield combination of Cameron McIntyre and Niva Ta'auso.
Anthony Tuitavake moves from centre to right wing and Ben Atiga returns to fullback.
Lock Tom Donnelly has been bracketed with Bernie Upton although the former is suffering from an infection with his availability to be confirmed on Saturday.
Even though the Junior All Blacks have already won the inaugural competition with a game in hand, Cooper insists his players will not lose their focus against Japan.
"I am not sure how many people know this, but the former New Zealand Juniors side lost to Japan in 1968.
"Saturday's match is a true international and we will approach it as such," Cooper said.