Tournaments are the way to maximize your ROW holdings. Every tournament features 32 players, and only users with enough XP can participate (though the XP threshold is set separately for each tournament). There is no entry ticket fee for a tournament; the prize fund is supplied by the platform.
To get whitelisted, go to the Tournament tab in the Arena and click on Join. Your highest-level card will be automatically picked for the tournament; if you have more than one card of that level, one of them will be picked randomly.
Tournaments follow the standard single elimination format, with 16 knockout battles in Round 1, followed by 8 battles between the Round 1 winners, then the quarter-finals, semi-finals, and the final. Every new round takes place 24 hours after the previous one, so that the whole tournament takes 5 days.
You’ll be automatically assigned a spot in the tournament schedule, and you need to have at least one card to proceed. If the original card with which you won the first round becomes unavailable for some reason (e.g. if you sell it, or put up it for sale), you’ll be considered defeated on technical grounds.
Just like in all other battles, the result of each encounter is probabilistic, with the same win chances for any combination of levels.