Resources

Magic: The Gathering Comprehensive Rules Changes

Core Set - Ninth Edition to Ravnica: City of Guilds (Single Change View)

General changes

Old rule (Core Set - Ninth Edition) New rule (Ravnica: City of Guilds)

Cost

Playing spells and activated abilities requires paying a cost. Most costs are paid in mana, but they may also include paying life, tapping or sacrificing permanents, discarding cards, and so on. A player can't pay a cost unless he or she has the necessary resources to pay it fully. For example, a player with only 1 life can't pay a cost of 2 life, and a permanent that's already tapped can't be tapped to pay a cost. See rule 203, "Mana Cost and Color," and rule 403, "Activated Abilities."

Cost

Playing spells and activated abilities requires paying a cost. Most costs are paid in mana, but costs may also include paying life, tapping or sacrificing permanents, discarding cards, and so on. A player can't pay a cost unless he or she has the necessary resources to pay it fully. For example, a player with only 1 life can't pay a cost of 2 life, and a permanent that's already tapped can't be tapped to pay a cost. See rule 203, "Mana Cost and Color," and rule 403, "Activated Abilities."