Coach Joe Schmidt handed scrum-half Luke McGrath his first Test start as part of a revamped backline in which winger Keith Earls is the only survivor.

Simon Zebo, Andrew Conway, Rory Scannell and Paddy Jackson also come into the backs, while flanker Dan Leavy for Josh van der Flier is the only change in the forwards.

Saturday's game in Shizuoka, the first of two Tests, comes after Ireland ran in nine tries in their 55-19 victory over the United States last week.

Ireland have never lost to Japan, the 2019 World Cup hosts, but their last Test series against them was 12 years ago in 2005.

Ireland (15-1): Simon Zebo; Andrew Conway, Garry Ringrose, Rory Scannell, Keith Earls; Paddy Jackson, Luke McGrath; Jack Conan, Dan Leavy, Rhys Ruddock (capt); Devin Toner, Quinn Roux; John Ryan, Niall Scannell, Cian Healy

Replacements: James Tracy, Dave Kilcoyne, Finlay Bealham, Kieran Treadwell, Jack O'Donoghue, Kieran Marmion, Rory O'Loughlin, Tiernan O'Halloran