A new biennial international rugby competition featuring all 10 teams from the Six Nations and Rugby Championship is set to start in 2026, their organizers said Saturday.

Two more unions will be invited to join the Six Nations Rugby sides -- England, France, Ireland, Italy, Scotland and Wales -- and the four Rugby Championship teams -- Argentina, Australia, New Zealand and South Africa. One of the two unions is likely to be Japan, according to Reuters and British media.

The tournament will be played in the existing July and November test windows, the organizers said, adding that a second-tier competition will be created to facilitate promotion and relegation from 2030.

Ireland captain Johnny Sexton (bottom, C) holds the Six Nations trophy at the end of their Six Nations rugby union international match against England at the Aviva Stadium in Dublin on March 18, 2023. (Getty/Kyodo)

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