Image source, Getty ImagesImage caption, Ireland beat Japan 41-10 in Dublin in November
Ireland's Nations Championship fixture against Japan will take place at McDonald Jones Stadium in Newcastle, Australia on 11 July (11:00 BST).
Andy Farrell's side open the inaugural tournament against Australia in Sydney on 4 July and will face the Brave Blossoms before travelling to New Zealand to take on the All Blacks at Auckland's Eden Park on 18 July.
Ireland have won 10 out of 11 Tests with Japan, the sole defeat coming at the 2019 Rugby World Cup at Shizuoka Stadium. Ireland won the last meeting 41-10 in Dublin last November.
After July's fixtures, Ireland will host Argentina, Fiji and South Africa in November at Aviva Stadium.
The biennial 12-team Nations Championship comprises six rounds of matches across the summer and autumn Test windows before a 'finals weekend' on 27-29 November at Twickenham's Allianz Stadium.
After each team has played the other six from the opposing hemisphere once, they are ranked within their own hemisphere.
The finals weekend in London will start with the sixth-placed northern hemisphere side taking on their southern hemisphere equivalent, and culminate in the two group winners taking each other on for the title.
The results on the finals weekend will also contribute to a north v south overall score and title.