Cost

A cost (コスト Kosuto) is a mandatory part of an effect, separated from the rest of the effect by a semicolon, which must be paid at the beginning of the effect's activation. The cost itself is not activated, cannot be negated, and does not start a Chain.

When an effect features a cost, the effect is activated (up to the colon), the cost is paid (up to the semicolon), the opponent has an opportunity to respond to the effect's activation, and the effect is resolved (up to the final period). Costs cannot be refunded; even if the activation of the effect is negated (or, for a Continuous effect, if the card is destroyed in a chain), the cost remains paid.

If a cost cannot be fully paid (for example, if an active effect prevents the cost from being paid, or the player cannot fulfill the requirements for the cost), the effect cannot be activated.

If a cost starts with "You can ...", the effect is optional and the cost is only paid if the player chooses to activate the effect.

As the name suggests, costs usually involve the player making a sacrifice of some type, such as reducing Life Points (e.g. "Seven Tools of the Bandit" requires a payment of 700 Life Points), destroying, Tributing, or banishing a card(s) (e.g. "Cannon Soldier" requires 1 monster to be Tributed), sending a card(s) to the Graveyard, or discarding a card(s) from the hand. Not all costs are negative to the player activating the effect; for example, "Lava Golem" requires two monsters to be Tributed from the opponent's side of the field.

A maintenance cost is a cost required to keep a card on the field. These costs are typically paid during a player's Standby or End Phase.

Examples

Negation of "Seven Tools of the Bandit"

• Step 1: Player A activates "Mirror Force".
• Step 2: Player B activates "Seven Tools of the Bandit" and pays 1000 Life Points.
• Step 3: Player A activates "Solemn Judgment" and pays half their Life Points.

• Step 3 resolves: "Solemn Judgment" negates and destroys "Seven Tools of the Bandit".
• Step 2 doesn't resolve because "Seven Tools of the Bandit" was negated. The Life Points paid when "Seven Tools of the Bandit" was activated are not refunded.
• Step 1 resolves: The effect of "Mirror Force" resolves.

Negation of "Premature Burial" in a chain

• Step 1: Player A activates "Premature Burial" and pays 800 Life Points, and then chooses the "Jinzo" in their Graveyard as the target.
• Step 2: Player B chains "Magic Jammer" and discards 1 card from their hand to negate "Premature Burial".

• Step 2 resolves: "Magic Jammer" negates the effect of "Premature Burial".
• Step 1 does not resolve because "Premature Burial" was negated. No monster is Special Summoned. The Life Points paid when "Premature Burial" was activated are not refunded.

Destruction of "Premature Burial" in a chain

• Step 1: Player A activates "Premature Burial" and pays 800 Life Points, and then chooses the "Jinzo" in their Graveyard as the target.
• Step 2: Player B activates "Mystical Space Typhoon" to destroy "Premature Burial".

• Step 2 resolves: "Mystical Space Typhoon" destroys "Premature Burial".
• Step 1 does not resolve because "Premature Burial" was destroyed; because it is an Equip Spell Card, the card's effect relies on it continuing to be in play in order to activate. No monster is revived. The Life Points paid when "Premature Burial" was activated are not refunded.

Chaining "Mask of Restrict" to the effect of "Cannon Soldier"

• Step 1: Player A Tributes a monster and activates the effect of their "Cannon Soldier" during their Main Phase 2.
• Step 2: Player B activates "Mask of Restrict", chaining it to the effect of "Cannon Soldier".

• Step 2 resolves: "Mask of Restrict" is in play and prevents monsters from being Tributed.
• Step 1 resolves: The monster was already Tributed before "Mask of Restrict" was successfully resolved. Therefore the effect of "Cannon Soldier" resolves and Player B loses 500 Life Points. Because "Mask of Restrict" is active, further Tributes cannot take place.