1.  Game Concepts

121.  Counters

121.1  A counter is a marker placed on an object or player that modifies its characteristics and/or interacts with a rule, ability, or effect. Counters are not objects and have no characteristics. Notably, a counter is not a token, and a token is not a counter. Counters with the same name or description are interchangeable.

121.1a  A +X/+Y counter on a creature or on a creature card in a zone other than the battlefield, where X and Y are numbers, adds X to that object’s power and Y to that object’s toughness. Similarly, -X/-Y counters subtract from power and toughness. See rule 613.3.

121.1b  The number of loyalty counters on a planeswalker on the battlefield indicates how much loyalty it has. A planeswalker with 0 loyalty is put into its owner’s graveyard as a state-based action. See rule 704.

121.1c  If a player has ten or more poison counters, he or she loses the game as a state-based action. See rule 704. A player is "poisoned" if he or she has one or more poison counters. (See rule 810 for additional rules for Two-Headed Giant games.)

121.2  Counters on an object are not retained if that object moves from one zone to another. The counters are not "removed"; they simply cease to exist. See rule 400.7.

121.3  If a permanent has both a +1/+1 counter and a -1/-1 counter on it, N +1/+1 and N -1/-1 counters are removed from it as a state-based action, where N is the smaller of the number of +1/+1 and -1/-1 counters on it. See rule 704.

121.4  If a permanent with an ability that says it can’t have more than N counters of a certain kind on it has more than N counters of that kind on it, all but N of those counters are removed from it as a state-based action. See rule 704.

121.5  If an effect says to "move" a counter, it means to take that counter from the object it’s currently on and put it onto a second object. If the first and second objects are the same object, nothing happens. If the first object has no counters, nothing happens; the second object doesn’t get a counter put on it. If the second object (or any possible second objects) is no longer in the correct zone when the effect would move the counter, nothing happens; a counter isn’t removed from the first object.

121.6  Some spells and abilities refer to counters being put on an object. This refers to putting counters on that object while it’s on the battlefieldand alsoto an object that’s given counters as it enters the battlefield.

121.6a  If an object enters the battlefield with counters on it, the effect causing the object to be given counters may specify which player puts those counters on it. If the effect doesn’t specify a player, the object’s controller puts those counters on it.