Règles complètes de Magic: The Gathering

705.1.

To flip a coin for an object that cares whether a player wins or loses the flip, the affected player flips the coin and calls «heads» or «tails.» If the call matches the result, that player wins the flip. Otherwise, the player loses the flip. Only the player who flips the coin wins or loses the flip; no other players are involved.

705.2.

To flip a coin for an object that cares whether the coin comes up heads or tails, each affected player flips a coin without making a call. No player wins or loses this kind of flip.

705.3.

A coin used in a flip must be a two-sided object with easily distinguished sides and equal likelihood that either side lands face up. If the coin that‘s being flipped doesn‘t have an obvious «heads» or «tails,» designate one side to be «heads,» and the other side to be «tails.» Other methods of randomization may be substituted for flipping a coin as long as there are two possible outcomes of equal likelihood and all players agree to the substitution. For example, the player may roll an even-sided die and call «odds» or «evens,» or roll an even-sided die and designate that «odds» means «heads» and «evens» means «tails.»