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COIN Chess (for up to 4 players)

Overview

4 player chess. 2 peasant players (white and black) and 2 noble players (white and black). Movement patterns remain untouched, but the game ends at king capture, rather than checkmate. In a typical chess game, this would occur 1 move after checkmate (it's implied, but too barbaric to actually go through with in a normal game), but in this variant, incentives are mixed and the kings don't always get their way. Moving into check (via castling also, but not through it) is allowed.

Pieces

Each peasant player controls pawns of their color. Each noble player controls the king and queen of their color. Pieces, aka "military" are potentially controlled by nobles or peasants.

Objectives

Noble objectives are checkmate as usual, but followed through until actual king capture. Peasant players' objectives are to end the game with as many pawns as possible on their side. A checkmate awards the winning noble 6 points, and 2 points for the winning side's peasants. Each pawn is worth 1 for its color's peasant player, regardless of which side got the checkmate. If a noble's side gets a checkmate without losing a single pawn, the noble gets a +4 bonus (the noble and peasant would each have 10 points – tying for the perfect assassination or diplomatic effort, or however else you'd like to consider it).

Factions and Teamwork

Each of the 4 players is allowed to collaborate openly or in secret with any of the other 3 factions in between any turn phase. That said, the noble/noble collaboration becomes unlikely as time goes on and peasants start sabotaging them (mid-late game) because for the nobles, it is a zero sum game once enough pawns are off the table.

Some players may feel motivated more by their "side" winning, whether that means "white," "black," or "peasants." Others might be mostly concerned with "place" or "ranking" among all of the players.

Types of Pieces

Pieces (knight, bishop, rook) are referred to as "military" in contrast with the pawns ("pawns"), and the king and queen ("nobles").

Turn phases

1. Noble Options

The noble player with military control has 6 options. A noble player without military control only has the options without the asterisks.

a) move the king

b) cede control to commoner player (from same side)

c)* castling (counts as (1e) if only one rook remains)

d)* move the queen

e)* force a pawn or unpaired military piece to move and relinquish military control on the next turn

f)* move a paired military piece

2. Commoner options (if control is ceded via (1b))

a) move a pawn

b) move a military piece that is unpaired (eg. if one 1 white rook has been captured, the white peasant player can move the remaining one at will during their phase). This doesn't include the queen, regardless of whether the noble has military control or not.

#Notes

  • A noble player begins the game with military control. Only (1e) loses military control for the noble player on the next turn.
  • After executing (1a) or (1b) (and the subsequent (2a) or (2b) from the (1b)), military control will return to the noble player on the following turn.
  • Only one player from either side (white or black) may move per turn. Ceding control (1b) is the only action that is followed by subsequent play by the same color.
  • All moves have to be legal chess moves.

Example Play

Opening

  1. White noble (with military control) cedes control to peasant. (noble will retain military control on next turn)

... white peasant moves a pawn to f3

  1. Black noble (with military control) forces pawn to e5 and loses military control on next turn

  2. White noble (with military control) forces pawn to f4 and loses military control on next turn

  3. Black noble (without military control) has no reasonable/legal king moves and cedes control to peasant (noble will regain military control on next turn)

... black peasant (after discussion with white peasant and determining a partnership unlikely) captures at f4

  1. White noble (without military control) doesn't like any king options and cedes control to peasant. (noble will regain military control on next turn)

... white peasant moves another pawn

Midgame

  1. White Noble (with military control) has 2 knights and 1 bishop. He prefers the bishop move, but decides instead to move the knight and retain military control on the next turn.

  2. Black Noble (without military control) cedes control to the peasant player, pleading for him to capture the open file with the single rook. Meanwhile, the white peasant player lobbies the black peasant player to move a lone knight in order to expose the king (put him in check).

  3. Black peasant exposes the king, hoping to take second place (white is ahead on pawn count)

  4. White noble (with military control) decides against capturing the king, hoping to whittle down black's pawns first.

Endgame

No specific examples of gameplay, but as the pieces whittle down, the dynamics change dramatically as peasants control all single units and refuse to promote pawns when they can avoid it. The chances for sabotage increase dramatically as paired military units become unpaired and peasants struggle to end the game before all of their pawns disappear.

Scoring Examples

White king captured, black has 5 pawns, white has 6 pawns.

white peasant - 6 black peasant - 7 black noble - 6 white noble - 0

Black king captured, black has 2 pawns, white has 3 pawns.

white noble - 6 white peasant - 5 black peasant - 2 black noble - 0

White king captured, 0 pawns left

black noble - 6 black peasant - 0 white peasant - 0 white noble - 0

White king captured, all pawns left

black noble - 10 black peasant - 10 white peasant - 8 white noble - 0

White king captured, 6 pawns each

black noble - 6 black peasant - 8 white peasant - 6 white noble - 0

Summary of who wins by length of game:

  • Fool's mate - Capturing team (peasant and noble)
  • slightly longer (-3 pawns each) - capturing team peasant
  • slightly longer (-4 pawns each) - capturing team (peasant and noble)
  • slightly longer (-5 pawns each) - capturing noble

Here dynamics shift and peasants lose faith in their leaders. Peasants just want a decisive end at this point.

Note: Promoted pawns do not factor into a peasant players pawn count at the end of the game.

With this point structure, there's also a chance at 8 or 7 pawns (assuming the other side has only 6 or 5) to sabotage in order to take first place or go for a tie.

Don't have 4 players?

No problem. Fewer players can take over multiple roles. With two players, you could have one player control the white peasant and black noble (vs. BP and WN), or control both white roles (WN/WP), or control just both peasants (BP/WP) or nobles (WN/BN). Additionally, a weaker player could be given 3 roles for a very asymmetric experience (eg. BP/WP/BN vs. WN). For 3 player games, one player (perhaps one familiar with COIN Chess) could control 2 roles.

In any situation that a player controls both roles for a given color, they will likely play exactly the same as in regular chess, except for any negotiations, backstabbing and deals cut with either faction on the other side.

Open questions and possible adjustments

Balance of factions and roles

It is currently known whether a certain combination of factions is overpowered against other combinations of factions. Is a BP/WP collaboration unbeatable? Is an early BN/WN collaboration able to guarantee that one noble will place ahead of the peasants? Do collaborations along color lines (BP/BN vs. WP/WN) favor peasants or nobles? Does an opposite color collaboration across roles (eg. BP/WN vs. BN/WP) favor peasants or nobles?

The queen

In a way, she is paired and unpaired. In this version of the rules, she's unmovable by peasants and by the noble without military control. This would be the most obvious rule to adjust for balancing. So if it turns out that nobles are weak, allow the noble to move the queen without military control. If nobles are too strong, allow peasants to move the queen when the noble lacks military control. If nobles are far too strong, classify the queen as an unpaired military. Or maybe she could be under shared control.

Military

In addition to adjusting queen control, if the Noble side is found to be overpowered, one of the military type units (knights, bishops or rooks) might be able to be controlled as if unpaired or (if the noble side is weak) under shared control (no loss of military power when a noble uses an unpaired military unit).

License

Evan Burchard's COIN Chess is licensed under a Creative Commons Attribution 4.0 International License.

![alt text] [cc] [cc]: https://i.creativecommons.org/l/by/4.0/88x31.png "Creative Commons License"

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