UEFA's first new 'Nations League' -- the competition which is being brought in to replace a number of friendly dates -- will be played between September and November 2018, UEFA said on Thursday.
Each country will play six matches in the new tournament, which will see UEFA's 52 countries split into four divisions, each with four groups of three or four teams. Teams will be grouped on strength, and there will be promotion and relegation between the groups.
The winners of the four groups in division A, which will be made up the strongest teams, will play the semifinals and final in June 2019 to become the UEFA Nations League champions.
The four semifinalists will also qualify automatically for the finals of Euro 2020, which is being played in 13 countries across Europe with the final at London's Wembley stadium.
"The key driver of the UEFA Nations League is sporting integrity, as member associations, coaches, players and supporters increasingly feel that friendly internationals are not providing adequate sporting competition," UEFA said in a statement.
"In addition, the competition will help UEFA realise its stated goal of improving the quality and standing of national team football while maintaining the balance between club and international football.
"The competition will establish the UEFA Nations League champions every odd year while also allowing all nations to play competitively at their level."
The Nations League placings will determine the seedings for the Euro 2020 qualifying programme , when the top two in 10 groups will join the four semifinalists from the Nations League playoffs.