T.4.1- This is also called "playing" a spell or ability. [D'Angelo 1999/05/01]
T.4.2- Announcing a spell or ability can be charted out like this: [CompRules 1999/04/23] [WotC Rules Team 2000/06/06] a) Announce the spell or ability to be played and put it on the stack. If the spell is a split spell (see Rule K.24), choose which half of the spell will be played as it is put on the stack. b) If the spell or ability is modal (see Rule G.24), choose the mode. c) If the spell or ability has an alternate cost, choose whether or not to use it. d) If Buyback (see Rule A.10), Kicker (see Rule A.24) or other optional cost is available, choose if it will be paid. e) If the spell or ability has an {X} in the mana cost, the value for X is chosen. f) Targets (if any) are chosen. See Rule G.39. g) If targets are affected differently, choose how each target is affected. This includes dividing up counters and damage. h) Determine the cost. Once determined, payment in step j will not change this cost. i) Mana abilities may be played at this point (or before announcing). j) Pay all costs. See Rule G.6.
T.4.3- Choices selected by the opponent are made during the same step as choices made by the player announcing the spell or ability, but they are made after that player makes any of their choices. [CompRules 1999/04/23] [WotC Rules Team 2000/04/04]
T.4.4- When announcing an ability, put a "pseudospell" on the stack which has a copy of the text and color of the permanent generating the ability. [CompRules 1999/04/23] This is like putting an invisible copy of the card on the stack.
T.4.5- If the cost includes mana, mana abilities can be played at substep 'i'. Or, you could have played the mana abilities before announcing the spell or ability. [CompRules 1999/04/23]
T.4.6- You cannot go through announcement if you cannot choose the required valid targets or cannot pay all the costs. [CompRules 1999/04/23] If you try to do so, the game "rewinds" to just before the announcement started.
T.4.7- When a spell says "Play this spell only any time you could play
a
T.4.8- The spell card is not in your hand after you start announcing it. [D'Angelo 1999/05/01]
T.4.9- You cannot choose to target something (in step 'f' of Rule T.4.2) then choose to do nothing to it or to do zero damage to it (in step 'g'). If this is the case, you simply do not include that target. [CompRules 1999/04/23]
T.4.10- If a spell or ability has multiple costs to be paid on announcement, the costs may be paid in any order you choose as long as you pay them all. They are not simultaneous. [CompRules 1999/11/01] For example, a Llanowar Elves cannot tap to attack and tap to pay its own Propaganda cost at the same time. It can only do one or the other. And a Llanowar Elf can tap to pay part of the cost of the Fling it is being sacrificed to. [DeLaney 1999/06/13]
T.4.11- If any spell or ability checks a characteristic or other value of a spell at the time it was played (as with Mana Maze), use the values at the start of the announcement (see Rule T.4.2 part a). For example, if you control both an Ivory Cup and a Iron Star and you announce a white spell that becomes red during the process of announcement, the Ivory Cup triggers and the Iron Star does not, because it was white at the start of announcement. [Dommermuth 2000/10/26] This applies to all values set at the start of announcement. Some values are set during announcement, such as the value of 'X' in a spell with an X in its cost. When these values are checked by a spell or ability, use the value at the time it was first determined. [D'Angelo 2000/11/06]
T.4.12- Check for any effects that prohibit something from being played at the time you start announcement (see Rule T.4.2 part a). You can't start an announcement if it is prohibited. [Dommermuth 2000/10/26] If a change occurs during announcement that would make the spell or ability be prohibited, that's okay. You've already passed the test at the start of announcement. Note: This rule applies only to effects which prohibit announcement. You still abort announcement if at any time you cannot complete the required payments, choose the required targets, or any other required actions. [D'Angelo 2000/11/06] Some spells and abilities may be allowed only if you take some additional action, such as with Rout requiring an additional payment if you want to play it at a time when a sorcery would not be allowed. For these cases, you may start announcing, but abort if you cannot make the required payment or other action at the required time. [D'Angelo 2000/11/17]
T.4.13- You determine the total cost of playing spell or ability at step 'h' in Rule T.4.2, then you get a chance to use mana abilities in step 'i' prior to paying costs in step 'j'. Any actions made while paying the cost or acquiring mana for the cost will not alter the cost. [Rules Team 2002/10/01]
T.4.Ruling.1- Any abilities that trigger (see Rule A.4) during this step are handled at the beginning of the next step. [D'Angelo 1999/05/01]
T.4.Ruling.2- Because of Rule T.4.4, destroying or modifying the source of an ability after it is announced will not cause the ability to fail or change in any way. [D'Angelo 1998/02/03]
T.4.Ruling.3- If an alternative cost has a condition, check the condition at the time you would pay the cost. [MM FAQ 1999/09/22]
T.4.Ruling.4- As an exception to rule T.4.9, you can target something with an effect that "rounds down" damage knowing that it will round down to zero. [DeLaney 2000/01/22]
T.4.Ruling.5- As noted in Rule T.4.2, any additional or optional play costs are dealt with after the spell or ability is on the stack. [CompRules 2002/02/20 - 412.3] Note that previously made choices, such as choosing to use Flashback, may restrict your options when making choices. [CompRules 2002/02/20 - 409.1b]
Note- Many choices are not made on announcement. They are made on resolution. If you don't see the choice described in this section, it is done on resolution. [D'Angelo 1999/05/01]
Note- If more than one target is to be selected at the same time, the same target may not be selected more than once. See Rule G.39.2.
Note- A spell that will become a permanent cannot be acted upon as a permanent until it is successfully resolved. Until then it is not a permanent, it is just a spell on the stack. [D'Angelo 1999/05/01]
Note- Replacement effects (see Rule T.10) can be applied to costs. See Rule T.10.Ruling.3.