X

For the Core Set, see 10th Edition.

On a card X can mean two different things:

• In the casting cost, is a variable mana cost of a spell.
• In a text box it means a variable, such as "Gain X life" or "Deal X damage" which is usually based on the in the mana cost of the spell.

Rules

From the ()

Rulings

• If a spell or ability has a cost with an “{X}” in it, the value of X must be announced as part of playing the spell or ability. (See rule 409, “Playing Spells and Activated Abilities.”) While the spell or ability is on the stack, the File:Manax.gif in its mana cost equals the amount announced as part of playing the spell or ability. If a card in any other zone has File:Manax.gif in its mana cost, the amount is treated as 0. If you’re playing a spell that has File:Manax.gif in its mana cost and an effect lets you play it without paying any cost that includes File:Manax.gif, the only legal choice for File:Manax.gif is 0. This does not apply to effects that only reduce a cost, even if they reduce it to zero. See rule 409, “Playing Spells and Activated Abilities.”
• If a cost associated with a special action, such as a suspend cost or a morph cost, has an “{X}” in it, the value of File:Manax.gif is chosen by the player taking the special action as he or she pays that cost.
• In triggered abilities, X is defined when the ability resolves. It may be defined by the text of the ability, by a keyword ability of the card, or by the trigger event. See rule 410, “Handling Triggered Abilities.”
• In other cases, X is defined by the text of a spell or ability. If X isn’t defined, the controller of the spell or ability chooses the value of X. All Xs on an object have the same value.

Trivia

• Shifting Wall is the first card to ever have a mana cost of just .
• The mana cost symbols and File:Manaz.gif (with the same function as ) are obsolete.

See also and Numbers and symbols