The purpose of of the TimeTurn system is to force players (who might otherwise intend to wait for perfect circumstances) into matches.
Each turn is accompanied by a time limit, the amount depends on what area you're in. When the time limit reaches 0 the player loses a turn and is booted to the Mainhall if they're not already there.
Any movement to or from the Mainhall (not including Matches) costs a turn.
If a player runs out of turns (0 turns+0 time) they're forced into a match. When the player leaves the match their turns will be refilled.
Within the match, turns continue to tick down from whatever turn the player entered, using the match area's time limit. If the player is in the match area but without an opponent, the player is considered in Limbo and will stay there waiting for an opponent until they run out of turns (0 turns+0 time) at which point they are ejected from Limbo. Inside a match proper, turns no longer eject you but are used as part of table splitting.
Tournament Mode Endgame
Within Tournament Mode the maximum turns scale down as the game enters the endgame by never allowing the maximum turns to be equal to the amount of players in the game, instead the maxturns are 1 lower. For example with 3 players left in the game the maxturns will be 2 giving each player only 2 turns to perform non-match actions.
Additionally, when the playercount reaches 2 an endgame countdown will begin. If the game has not ended naturally before the countdown ends, the game will be ended by force and the 2 players will have their remaining cards counted against them in the leaderboard results.