Editing In play

A card is said to be '''in play''' if it is in the '''play area'''—the location cards are put when you play them. Under ordinary circumstances, a card enters the play area when you play it, and leaves play when discarded during the [[Clean-up]] phase of that turn. [[Reserve]] cards also enter the play area when you [[call]] them.

There are a handful of cards, the [[Command variant|Command variants]], which instruct you to play a card ''without'' putting it in play; there are also some situations where the [[stop-moving rule]] prevents a played card from entering the play area.

Ordinarily cards leave the play area by being discarded during the [[Clean-up]] phase of the turn on which they enter play, though several exceptions exist:
* [[Duration]] cards, and Command variants playing Duration cards, remain in play until the Clean-up phase of the last turn on which they are expected to have an effect; [[Throne Room variant]]s playing Duration cards remain in play until the Clean-up phase of the turn when the Duration leaves play.
* [[One-shot]]s, [[Reserve]] cards, and certain other cards have instructions to remove themselves from play as a result of playing them.
* Some cards, [[Event]]s, and [[Way]]s have abilities that cause you to remove other cards from play before the Clean-up phase: for example, {{card|Mandarin}} top-decks [[Treasure]] cards from play when you gain it, and {{card|Bonfire}} [[trash]]es cards from play when you buy it.

Some cards and [[card-shaped things]] have abilities that depend on what is in play at a given time. For example, {{card|Peddler}} changes its own [[cost]] depending on how many [[Action]] cards are in play during the Buy phase.

== While-in-play abilities ==

Several cards have abilities that are activated '''while the card is in play'''; typically these are listed below a horizontal dividing line in the card text. Since these abilities begin to take effect when you play the card, it is easy to mistake them for abilities that are triggered ''by'' playing the card. However, "while-in-play" effects differ from "on-play" (or "above-the-line") effects in several ways:
* If you play the same card multiple times on the same turn via a Throne Room variant, its "on-play" abilities happen each time you play it; but there is only one copy of the card in the play area, so its while-in-play abilities only happen once.
* If a card is played by a Command variant, it never enters play, so its while-in-play abilities never activate but its on-play effects do. Similarly, if a card is removed from play prematurely, its while-in-play abilities cease to operate, but any persistent on-play abilities remain in effect.
* {{card|Enchantress}} and [[Way]]s overrule the on-play abilities of an [[Action]] card, but leave the while-in-play abilities unchanged.
Sometimes the same abilities are present as on-play abilities on some cards and while-in-play abilities on others. For example, {{card|Bridge}} and {{card|Inventor}} provide [[cost reduction]] as an on-play ability; but {{card|Quarry|oi=3}} (prior version), {{card|Highway|oi=2}} (prior version), {{card|Bridge Troll|oi=2}} (prior version), and {{card|Princess}} (prior version) provide cost reduction while in play. Similarly, {{card|Guardian}} and {{card|Champion}} provide [[attack immunity]] as an on-play ability, but {{card|Lighthouse}} does so as a while-in-play ability.

=== List of cards with while-in-play abilities ===
<p>Cards in italics have been [[Removed cards|removed]].</p>
* {{set|Seaside}}: {{card|Lighthouse|oi=3}} (prior version)
* {{set|Prosperity}}: {{card|Quarry|oi=3}} (prior version), ''{{card|Talisman}}'', ''{{card|Royal Seal}}'', ''{{card|Goons}}'', {{card|Hoard|oi=3}} (prior version)
* {{set|Cornucopia}}: {{card|Princess}} (prior version)
* {{set|Hinterlands}}: {{card|Haggler|oi=2}} (prior version), {{card|Highway|oi=2}} (prior version)
* {{set|Dark Ages}}: {{card|Urchin}}
* {{set|Guilds}}: {{card|Merchant Guild|oi=2}} (prior version)
* {{set|Adventures}}: {{card|Bridge Troll|oi=2}} (prior version)
* {{set|Empires}}: {{card|Groundskeeper}} (prior version)
* {{set|Nocturne}}: {{card|Tracker|oi=1}} (prior version)
* [[Promo]]: {{card|Sauna}} (prior version)

== Trivia ==

There are no while-in-play abilities in the first two Dominion sets, the {{set|Base}} set and {{set|Intrigue}}. [[Donald X. Vaccarino]] introduced while-in-play abilities in order to avoid tracking difficulties, so that players could simply inspect the cards that were visible in the play area in order to determine what abilities were in effect. 
{{Quote|
|Text=
The purpose is tracking. "While this is in play" is always in play to show off that it's doing something (or isn't in play and so isn't doing anything). "This turn" effects like {{Card|Coppersmith}} / {{Card|Bridge}} might not be. It's not that I want to screw over {{Card|Throne Room|Throne}}/{{Card|Procession}} + {{Card|Highway}} or whatever, it's that {{Card|Procession}} + {{Card|Bridge}} makes you have to remember the Bridge effect.

It's fun to {{Card|Throne Room|Throne}} a {{Card|Bridge}} and so there's that. In general "while this is in play" is just better though.

Similarly {{Card|Conspirator}} looks at how many action cards you played this turn, but {{Card|Peddler}} counts the action cards in play. {{Card|Peddler}}'s approach is better; no tracking.
|Name=[[Donald X. Vaccarino]]
|Source=[http://forum.dominionstrategy.com/index.php?topic=5799.msg148785;topicseen#msg148785 Interview with Donald X.]
}}
At one point he contemplated revising earlier cards such as {{card|Bridge}} to use while-in-play wording, though he did not end up making this change. 
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I would consider whether I like {{card|Bridge}} and {{card|Coppersmith}} as is, in their Throne-able glory, or if I would rather phrase them the way I think such stuff in general should be phrased, like {{card|Highway}} etc.
|Name=[[Donald X. Vaccarino]]
|Source=[http://forum.dominionstrategy.com/index.php?topic=3179.msg56362#msg56362 With my Dominion Time Machine...]
}}
Later, he discovered that players find while-in-play abilities more confusing than on-play abilities, and stopped using while-in-play abilities on new cards; the while-in-play mechanic has not been used since {{set|Nocturne}}.
{{Quote|
|Text=
I switched from "this turn" to "while this is in play" because "while this is in play" has better tracking; you e.g. {{Card|Procession}} a {{Card|Highway}} and the card no longer in play no longer does anything, hooray. [In {{set|Renaissance}}] I switched back to "this turn" because it turned out people get more confused by "while this is in play."
|Name=[[Donald X. Vaccarino]]
|Source=[http://forum.dominionstrategy.com/index.php?topic=20566.msg857191#msg857191 Inventor wording]
}}
Finally, in 2022, all cards with "while this is in play" received errata to "this turn."
{{Quote|
|Text=
[While this is in play] also endlessly confuses players. Who are these players, someone is asking. Man. They're everywhere. Maybe you are in a bubble of rules experts, I dunno; they're really out there. They are surprised when {{Card|Throne Room|Throne}} - {{Card|Goons}} doesn't work and so on.

The {{Card|Highway}} cost-reduction feels just like {{Card|Bridge}}'s, but there are all these things that are actually different. This really honestly truly confuses people. Part of this for me was that I misphrased {{Card|Conspirator}} back when. It cares about cards you played; isn't it simpler to count the cards in play? Then you don't have to remember e.g. that {{Card|Mining Village}} that vanished. {{Card|Peddler}} does it the correct way. But well. Translating this to doing {{Card|Highway}} instead of {{Card|Bridge}} just endlessly confused people. I thought it was better for a few years there but eventually I saw the light. Again you may note a lack of such cards in recent expansions.

"This turn" seems straightforward in most cases. Some of these cards have other changes too; I didn't forget them. I'm not on a crusade to get rid of dividing lines; it's "while this is in play" that was specifically confusing.
|Name=[[Donald X. Vaccarino]]
|Source=[http://forum.dominionstrategy.com/index.php?topic=21326.msg894048#msg894048 The Why of the Errata]
}}
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[[category:Rules]]