magic the gathering rules 1/1 counters

[DanMTG]

What are the rules for 1/1 counters

[Urza]

120. Counters
120.1. 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.
120.1a A +X/+Y counter on a permanent, where X and Y are numbers, adds X to that permanent’s
power and Y to that permanent’s toughness. Similarly, -X/-Y counters subtract from power and
toughness. See rule 612.3.
120.1b 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.
120.1c. If a player has ten or more poison counters, he or she loses the game as a state-based action.
See rule 704.
120.2. 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.
120.3. 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.
120.4. 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) are no longer in the correct zone
when the effect would move the counter, nothing happens; a counter isn’t removed from the first
object.
120.5. If a spell or ability refers to a counter being “placed” on a permanent, it means putting a counter
on that permanent while it’s on the battlefield, or that permanent entering the battlefield with a
counter on it.