Capture

The elimination or change of ownership of an game element.

Many games contain events that remove game elements from play. Traditionally this is called to Capture the pieces, even if this may mean removing them or transforming them to so they become another player's pieces.

Note: While Board Games typically use the term Capture, Real-Time Games instead uses Eliminate. For this pattern collection, Eliminate is seen as a more specific form of Capture due to being a newer form of the same phenomena.

Examples

Board Games show many different ways to Capture enemy pieces: Hnefatafl by surrounding a piece from two opposing sides (four for the king), Go by completely enclosing an enemy group of stones, and Chess and Stratego by replacing a piece with ones own. It is also worth noticing that Go allows players to make their own groups be captured for larger tactical reasons while there exists specific rules for which pieces can Capture which pieces in Stratego.

Qix allows the player to catch computer-controlled units by enclosing them in the smaller area of the two areas that are created by outlining a path in the unmarked part of the game area.

Priests in Age of Empires series can convert pieces controlled by other players as their main offensive action.

Using the pattern

Three main decisions need to be done for each type of Capture allowed in games: which game elements can perform the Capture, which game elements can be the targets, and what actions are required to activate the Capture. Traditionally Units have been the game elements that can capture with rare appearances of Avatars through King pieces in for example Chess (Units will be referred to mostly in the following but unless explicitly noted this could be replaced by Avatars). Many games, e.g. Chess, Go, and Draughts, make no distinction of which game elements can Capture, but the Bombs in Stratego cannot move and therefore not actively try to Capture other pieces. Likewise, most pieces can be the target of Capture actions but Hnefatafl has special requires for capturing the king piece and Stratego as special rules for which Units can Capture which. Combined with the Imperfect Information in Stratego, this makes capturing there have an element of Risk/Reward.

Parlett lists 7 ways to Capture in board games: Custodianship, Displacement, Enclosure, Intervention, Leap, Approach, and Withdrawal. Custodianship consist of flanking a target by placing Units in Contact with it. This example of Combos can be found in ordinary Captures in Hnefatafl. Displacement is simply using Movement to enter the space occupied by the target and remove it, as is done for example in Chess. Enclosure, used in Go, requires placing Units in all spaces adjacent to the target or target group (the capture of the king in Hnefatafl can be seen as an example of this as well, or a double case of Custodianship). Intervention is the inverse of Custodianship but Parlett provides no examples.

Leap, Approach, and Withdrawal.

Parlett also notes that a Capture can be immediate (the most common case), or be a Delayed Effect that can open up for making it an Interruptible Action (as is argued to exist by those reconstructing the rules of Ludus Latrunculorum).

Parlett also mentions Conversion, which is the Transfer of Control of a game element to another players and which can be used as a modifier to any of the Capture methods listed (Reversi is an example of this), and makes conflates Capture with Gain Ownership.

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In approach the piece is captured by moving towards it in a straight line and stopping right next to it - displacement is a specific version of this used in for example Chess. Withdrawal is, obviously, the reverse of approach: the piece is captured by moving an adjacent piece away from it in a straight line. Intervention involves capturing enemy pieces by moving a piece between them to form a line. The captured piece in custodianship is flanked by friendly pieces in such a way that the pieces form a line, as for example is the case in Hnefatafl or Reversi where several pieces can be captured by flanking.

The goal pattern Eliminate is a more specific form of Capture and typically used for Real-Time Games, especially those using Aim & Shoot. It can be used to instantiate Capture but using other means allows less aggressive diegetic explanations of why game elements are removed, and what happens to them after they are removed.

Go

Bomb

Stratego

The prime design choice regarding Capture is to decide if the aim is to Eliminate or Gain Ownership, but can in both cases be seen as a struggle over Ownership. As Capture is most often done through the actions of a game element under a player's control, determining what game elements can be used to Capture is usually a part of defining the goal.

The game design must support some action that facilitates the Capture. In the case of Real-Time Games, this typically is Combat, Maneuvering, or Aim & Shoot promoting skills in Dexterity-Based Actions. Turn-Based Games favor the use of Puzzle Solving, and thereby Stimulated Planning, but can also make use of Investment or Bidding. The first type of game usually has the subgoal of Contact (with Qix as an example of Enclosure) while the second type of game commonly has subgoals such as Contact, Alignment, Enclosure, Configuration, and Connection.

Capture goals are very often related to Overcome goals in the Hierarchies of Goals. How they are related to each other depends primarily on their individual Reward structures and on players' tactics. Capture is often achieved by Movement but in Real-Time Games, this depends on Timing, while in Turn-Based Games, it more often is a form of Puzzle Solving, as players have to take other players or Agents actions into consideration due to Turn Taking.

Captures combined with Eliminate of game elements that are Non-Renewable Resources can quicken gameplay as fewer game elements remain and promote Higher-Level Closures as Gameplay Progresses since each element represents a greater part of players' Resources. When Capture allows Transfer of Control, this causes Preventing Goals such as Evade and can trigger retaliating Capture goals by an original owner to regain control. The control of a new game element through Capture can motivate New Abilities, possibly Privileged Abilities, to become available.

Real-Time Games Turn-Based Games Enemies Alignment

Relations

Can Instantiate

Combos

with Delayed Effects

Interruptible Actions

with Imperfect Information

Risk/Reward

with Transfer of Control

Gain Ownership

Can Modulate

Transfer of Control

Can Be Instantiated By

Avatars Eliminate Movement Units

Can Be Modulated By

Risk/Reward Contact Delayed Effects

History

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

Acknowledgements

Karl Bergström, Martin Eriksson, Peter Ljungstrand