Spoiler:

601. Casting Spells
601.1. Previously, the action of casting a spell, or casting a card as a spell, was referred to on cards as
“playing” that spell or that card. Cards that were printed with that text have received errata in the
Oracle card reference so they now refer to “casting” that spell or that card.
601.1a Some effects still refer to “playing” a card. “Playing a card” means playing that card as a
land or casting that card as a spell, whichever is appropriate.
601.2. To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its
costs, so that it will eventually resolve and have its effect. Casting a spell follows the steps listed
below, in order. If, at any point during the casting of a spell, a player is unable to comply with any
of the steps listed below, the casting of the spell is illegal; the game returns to the moment before
that spell started to be cast (see rule 717, “Handling Illegal Actions”). Announcements and
payments can’t be altered after they’ve been made.
601.2a The player announces that he or she is casting the spell. That card (or that copy of a card)
moves from where it is to the stack. It becomes the topmost object on the stack. It has all the
characteristics of the card (or the copy of a card) associated with it, and that player becomes its
controller. The spell remains on the stack until it’s countered, it resolves, or an effect moves it
elsewhere.
601.2b If the spell is modal the player announces the mode choice (see rule 700.2). If the player
wishes to splice any cards onto the spell (see rule 702.46), he or she reveals those cards in his or
her hand. If the spell has alternative or additional costs that will be paid as it’s being cast such as
buyback or kicker costs (see rules 117.8 and 117.9), the player announces his or her intentions
to pay any or all of those costs (see rule 601.2e). A player can’t apply two alternative methods
of casting or two alternative costs to a single spell. If the spell has a variable cost that will be
paid as it’s being cast (such as an {X} in its mana cost; see rule 107.3), the player announces the
value of that variable. If a cost that will be paid as the spell is being cast includes hybrid mana
symbols, the player announces the nonhybrid equivalent cost he or she intends to pay. If a cost
that will be paid as the spell is being cast includes Phyrexian mana symbols, the player
announces whether he or she intends to pay 2 life or the corresponding colored mana cost for
each of those symbols. Previously made choices (such as choosing to cast a spell with flashback
from a graveyard or choosing to cast a creature with morph face down) may restrict the player’s
options when making these choices.
601.2c The player announces his or her choice of an appropriate player, object, or zone for each
target the spell requires. A spell may require some targets only if an alternative or additional
cost (such as a buyback or kicker cost), or a particular mode, was chosen for it; otherwise, the
spell is cast as though it did not require those targets. If the spell has a variable number of
targets, the player announces how many targets he or she will choose before he or she
announces those targets. The same target can’t be chosen multiple times for any one instance of
the word “target” on the spell. However, if the spell uses the word “target” in multiple places,
the same object, player, or zone can be chosen once for each instance of the word “target” (as
long as it fits the targeting criteria). If any effects say that an object or player must be chosen as
a target, the player chooses targets so that he or she obeys the maximum possible number of
such effects without violating any rules or effects that say that an object or player can’t be
chosen as a target. The chosen players, objects, and/or zones each become a target of that spell.
(Any abilities that trigger when those players, objects, and/or zones become the target of a spell
trigger at this point; they’ll wait to be put on the stack until the spell has finished being cast.)
Exampl
e:
If a spell says “Tap two target creatures,” then the same creature can’t be
chosen twice; the spell requires two different legal targets. A spell that says “Destroy
target artifact and target land,” however, can target the same artifact land twice
because it uses the word “target” in multiple places.
601.2d If the spell requires the player to divide or distribute an effect (such as damage or counters)
among one or more targets, the player announces the division. Each of these targets must
receive at least one of whatever is being divided.
601.2e The player determines the total cost of the spell. Usually this is just the mana cost. Some
spells have additional or alternative costs. Some effects may increase or reduce the cost to pay,
or may provide other alternative costs. Costs may include paying mana, tapping permanents,
sacrificing permanents, discarding cards, and so on. The total cost is the mana cost or alternative
cost (as determined in rule 601.2b), plus all additional costs and cost increases, and minus all
cost reductions. If the mana component of the total cost is reduced to nothing by cost reduction
effects, it is considered to be {0}. It can’t be reduced to less than {0}. Once the total cost is
determined, any effects that directly affect the total cost are applied. Then the resulting total cost
becomes “locked in.” If effects would change the total cost after this time, they have no effect.
601.2f If the total cost includes a mana payment, the player then has a chance to activate mana
abilities (see rule 605, “Mana Abilities”). Mana abilities must be activated before costs are paid.
601.2g The player pays the total cost in any order. Partial payments are not allowed. Unpayable
costs can’t be paid.
Example:
You cast Altar’s Reap, which costs {1}{B} and has an additional cost of
sacrificing a creature. You sacrifice Thunderscape Familiar, whose effect makes your
black spells cost {1} less to cast. Because a spell’s total cost is “locked in” before
payments are actually made, you pay {B}, not {1}{B}, even though you’re sacrificing the
Familiar.
601.2h Once the steps described in 601.2a–g are completed, the spell becomes cast. Any abilities
that trigger when a spell is cast or put onto the stack trigger at this time. If the spell’s controller
had priority before casting it, he or she gets priority.
601.3. Some spells specify that one of their controller’s opponents does something the controller would
normally do while it’s being cast, such as choose a mode or choose targets. In these cases, the
opp
onent does so when the spell’s controller normally would do so.
601.3a If there is more than one opponent who could make such a choice, the spell’s controller
decides which of those opponents will make the choice.
601.3b If the spell instructs its controller and another player to do something at the same time as the
spell is being cast, the spell’s controller goes first, then the other player. This is an exception to
rule 101.4.
601.4. Casting a spell that alters costs won’t affect spells and abilities that are already on the stack.
601.5. A player can’t begin to cast a spell that’s prohibited from being cast.
601.5a If an effect allows a card that’s prohibited from being cast to be cast face down, and the
face-down spell would not be prohibited, that spell can be cast face down. See rule 707, “Face-
Down Spells and Permanents.”