Exchange

Exchange
Keyword Action
Introduced	Alpha (mechanic) Sixth Edition (keyword)
Last used	Evergreen
Reminder Text	No official reminder text
Statistics	52 cards 7.7% 50% 13.5% 3.8% 1.9% 3.8% 1.9% 1.9% 1.9% 13.5%
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fulloracle:"Exchange"

Exchange is a keyword action. One of the big things the Sixth Edition rules change did was to try to consolidate how Magic card text referred to things. The game had always had it, but it wasn't until then that exchange got its own vocabulary word.

Description

There are three major use cases for the action of "exchange", with a fourth obsolete use related to ante.

Control

The largest set of "exchangers" swap control between two permanents. Each must exist upon the battlefield during the resolution. There are two cards (Perplexing Chimera and Sudden Substitution) that exchanges a card from the stack, which is the only other zone where a player has control of an object - the exile zone has ownership but not control. Exchange of Words exchanges text boxes, but by itself the card is functionally close to an exchange of creatures plus a power/toughness setting effect.

Goblin Welder is a card that once had "exchange" in its rules text, but control changing effects meant the terminology needed to be spelt out. Aura Swap, a similar effect, has rules baggage preventing the effect if the controller of the aura swapper is not its owner. Finally, ante usage did not have this issue, as the changing of owners circumvented the "control can only change on the battlefield or stack" rule. As such, it could exchange objects from any zone, including the graveyard, hand and library.

Objects in zones

The second set of exchangers that swap all cards in two zones with each other - due to the nature of ownership and shared zones, this is limited to the hand, library and graveyard. One card of each exchange has been printed: Mordenkainen (hand and library), Harness Infinity (hand and graveyard) and Morality Shift (graveyard and library).

Numerical

Finally, there are a set of numerical value exchangers. Most commonly two life totals are exchanged, but a handful of cards exchange life total with power (Evra, Halcyon Witness) or toughness (Tree of Redemption and Tree of Perdition). Any change in life total will trigger effects that track life gain or loss. This also results in some amount of memory issue with exchanging life with power or toughness, as these effects are permanent, and the creature will continue to exist with an altered stat.

Separately, there are three cards that exchange power or toughness. Serene Master exchanges its power with a target creature it's blocking, while the Alchemy card High Fae Prankster allows for the exchange of base power and toughness. Vedalken Squirrel-Whacker allows for it's base power or toughness to be exchanged with a dice roll.

Rules

From the glossary of the Comprehensive Rules (June 7, 2024—Modern Horizons 3)

Exchange

To swap two things, such as objects, sets of objects, or life totals. See rule 701.10, “Exchange.”

From the Comprehensive Rules (June 7, 2024—Modern Horizons 3)

• 701.10. Exchange
  • 701.10a A spell or ability may instruct players to exchange something (for example, life totals or control of two permanents) as part of its resolution. When such a spell or ability resolves, if the entire exchange can’t be completed, no part of the exchange occurs.

    Example: If a spell attempts to exchange control of two target creatures but one of those creatures is destroyed before the spell resolves, the spell does nothing to the other creature.

  • 701.10b When control of two permanents is exchanged, if those permanents are controlled by different players, each of those players simultaneously gains control of the permanent that was controlled by the other player. If, on the other hand, those permanents are controlled by the same player, the exchange effect does nothing.
  • 701.10c When life totals are exchanged, each player gains or loses the amount of life necessary to equal the other player’s previous life total. Replacement effects may modify these gains and losses, and triggered abilities may trigger on them. A player who can’t gain life can’t be given a higher life total this way, and a player who can’t lose life can’t be given a lower life total this way (see rules 119.7–8).
  • 701.10d Some spells or abilities may instruct a player to exchange cards in one zone with cards in a different zone (for example, exiled cards and cards in a player’s hand). These spells and abilities work the same as other “exchange” spells and abilities, except they can exchange the cards only if all the cards are owned by the same player, and they can exchange the cards even if one zone is empty.
  • 701.10e If a card in one zone is exchanged with a card in a different zone, and either of them is attached to an object, that card stops being attached to that object and the other card becomes attached to that object.
  • 701.10f If a spell or ability instructs a player to simply exchange two zones, and one of the zones is empty, the cards in the zones are still exchanged.
  • 701.10g A spell or ability may instruct a player to exchange two numerical values. In such an exchange, each value becomes equal to the previous value of the other. If either of those values is a life total, the affected player gains or loses the amount of life necessary to equal the other value. Replacement effects may modify this gain or loss, and triggered abilities may trigger on it. A player who can’t gain life can’t be given a higher life total this way, and a player who can’t lose life can’t be given a lower life total this way (see rules 119.7–8). If either of those values is a power or toughness, a continuous effect is created setting that power or toughness to the other value (see rule 613.4b). This rule does not apply to spells and abilities that switch a creature’s power and toughness.
  • 701.10h One card (Exchange of Words) instructs a player to exchange the text boxes of two creatures. This creates a text-changing effect (see rule 612, “Text-Changing Effects”). In such an exchange, the rules text of each permanent becomes the previous rules text of the other.