To make this easier to find and because it is different for group stage and semifinal/final, I post this separately:
Group stage match (4 games = 4 different maps):
- Free hidden pick of civilisations. A civilisation can be repeated as often as the player likes in the 4 games, but in 3v3 not within one game.
Semifinal and Final Best of 5:
- Free hidden pick of civilisations, no repitition within one Best of 5. So in a 3v3 of 5 games, 15 different civilisations have to be picked in 1v1 5 civilisations.
Group stage match (4 games = 4 different maps):
- Free hidden pick of civilisations. A civilisation can be repeated as often as the player likes in the 4 games, but in 3v3 not within one game.
Semifinal and Final Best of 5:
- Free hidden pick of civilisations, no repitition within one Best of 5. So in a 3v3 of 5 games, 15 different civilisations have to be picked in 1v1 5 civilisations.