Discard Piles

Areas or stacks where cards or tiles are placed after they have been used.

Games that use cards, chips, or tiles often distinguish between those that have yet to come in play, those that are in play, and those that have been used. Discard Piles are used to keep track of used cards etc. While this may be for pure practical or aesthetic reasons, other uses are to let that these represent future drawing stacks or resource areas for those with abilities to take game elements from the Discard Piles.

Examples

The Rummy family of Card Games actively uses the Discard Pile as a resource from which players may draw cards. These Discard Piles are replenished continually as player must end their turns by discarding a card (except when emptying their hands in some versions). The goal of Uno is to get all ones cards into the Discard Pile. Players of Race for the Galaxy place the cards they have used as payment for actions in Discard Piles. When the drawing stack is empty, these Discard Piles are shuffled and used as new drawing stacks - meaning that discards cards can return to gameplay. Dominion and Thunderstone work the same way but here players have their own individual Discard Piles.

Cards in 7 Wonders are only discarded at the end of each era with the exception of cards discarded for money. The card are then permanently out of gameplay, except that the player controlling Helicarnassus which can pick a limited number of cards from the Discard Pile during a game instance (the leader Solomon provides this special ability once as well).

Although players may not perceive it, cards taken in No Thanks! are in effect placed in Discard Piles.

Using the pattern

Discard Piles can occur spontaneously in games where Cards or Tiles are played in some way; in some Card games, including all Collectible Card Games, the Discard Piles are temporary storage areas to ensure that all a player's Cards are used before any are reused. When given explicit rules, there are two main design choices related to designing Discard Piles: should they be open or closed, and should players be able to retrieve the Cards or Tiles in some way.

Discard Piles can be either closed or opened. Closed Discard Piles hide the important information of the game elements in them and do not let the players go through the piles; they provide advantages to players that can do Memorizing well although this may not be allowed according to rules (the most famous example being the cards played in Blackjack). Open Discard Piles, by contrast, either place the game elements so that they can all be seen or allow the players to go through the pile. These open piles support Stimulated Planning but may also cause Analysis Paralysis since they allow players a more complete view of the game state.

Retrieving Cards from Discard Piles is an action all players can do in the Rummy family of Card Games but 7 Wonders only allows this as a Privileged Ability. Games that allow this type of action effectively let Discard Piles affect what Hands players have. Some games with Discard Piles have a separate pile for Cards that for some reason should be removed from normal gameplay and only under rare circumstances can be return. Graveyard is the name for this area in Magic: The Gathering.

Games with Trick Taking may use a Discard Pile for each trick so that players may enact Replays after gameplay has finished.

Interface Aspects

Discard Piles is a Interface Pattern.

Consequences

The most basic function of Discard Piles is purely logistic: they define places where to place used game elements - most commonly Cards or Tiles. However, like Drawing Stacks the size of Discard Piles may function as a Game State Indicator since they allow players to judge how far the gameplay in a game has progress if game instances are limited by how many times Cards or Tiles are used. As mentioned above, open Discard Piles can increase the risk of Analysis Paralysis in games since it augmented the possibilities of Stimulated Planning. This can to a lesser extend be possible with closed Discard Piles since the size of the Discard Piles can provide some information as just mentioned. It should however be mentioned that this is more likely to be easily detected by looking at Drawing Stacks if these also exist.

Discard Piles make easy candidates for refilling Drawing Stacks, and when Cards or Tiles are recycled in this fashion the games that do this have Closed Economies. A related use of Discard Piles is to make them into Drafting Spreads since this is a way for players to refill their Hands; Rummy is an example of a game doing this but only has the last played Card as the Drafting Spread but a common variant is to use the whole Discard Pile and the Drafting Spread.

Relations

Can Instantiate

Drafting Spreads, Game State Indicators

with Drawing Stacks

Closed Economies

with Trick Taking

Replays

Can Modulate

Analysis Paralysis, Cards, Collectible Card Games, Drawing Stacks, Hands, Memorizing, Stimulated Planning, Tiles

Can Be Instantiated By

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Can Be Modulated By

Privileged Abilities, Trick Taking

Possible Closure Effects

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Potentially Conflicting With

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History

An updated version of the pattern Discard Piles that was part of the original collection in the book Patterns in Game Design.

Acknowledgements

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