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prisoner's dilemma card game

a game of strategy, trust and deception
  [vote for,

This is a card game based on the prisoner's dilemma. This could be played at a conference, convention or party.


• Each player starts with 20 cards of one colour and an envelope.

• There are one or more discard bins in the area of play.

• Any player can challenge any other player to a game.

• Once two players have agreed to play a game, each player puts either 1 or 2 cards in their own envelope.

• Players are free to talk during the game. Players can make promises, lie, tell the truth etc.

• After each player has put either 1 or 2 cards in their envelope, the envelopes are emptied to reveal how many cards were in each envelope


There are three possible outcomes for each game:

» If both players put two cards in their envelopes, all cards are discarded.
» If one player puts two cards, and the other puts one card, all cards go to the player who put in two cards.
» If both players put in one card, each player gets to swap their card.

• After a fixed period of time play stops. The player with the most cards (not of their own colour) wins.

The game could be played as teams, with players on the same team having the same colour cards.

xaviergisz, Mar 01 2018



       You could play this with a regular deck.
RayfordSteele, Mar 01 2018

       Nice. Like poker but even less about the cards.   

       In the best case, the aggressive move (playing two cards) only yields you the same number of *new* cards as the case where both players co-operate. Is that intended?
pertinax, Mar 02 2018

       The aggressive/cooperative play nets +1 card for the aggressive player and -1 card for the cooperative player, whereas the dual cooperative play nets each player 0 cards. That's the intention.   

       I haven't played it yet. It will be tested at a scout camp in 3 weeks with 300 scouts playing.
xaviergisz, Mar 02 2018

       Question - do players see the outcomes of other players' games? This could change the game-playing tactics - e.g. if you see a player accumulate loads of cards, you might conclude that this will increase the probability that when they play you they'll be prepared to risk putting two cards in.
hippo, Mar 02 2018

       Also, I think it might be better if card colour is irrelevant - winning is based just on the number of cards held
hippo, Mar 02 2018

       Yes, players can watch the other games. Rumours will spread about certain player tactics, strategies will vary as the game progresses. How the games will unfold is satisfyingly unpredictable. The one predictable outcome is some players getting annoyed.   

       The card colour rule is there to prevent the play- refusers from winning.
xaviergisz, Mar 02 2018

       You can get round that by not allowing anyone to refuse a game
hippo, Mar 02 2018

       It's the card-colour rule which makes the "both co-operate" outcome +1, not 0.
pertinax, Mar 02 2018

       I think making card colours matter distorts the game-play. I see the cards as like money and the winner of the game is just the player with most 'money'. There's no different coloured money.
hippo, Mar 02 2018

       //It's the card-colour rule which makes the "both co- operate" outcome +1, not 0.//   

       Good point. Depending on how long the game lasts, it might get to the point when players don't hold any cards of their original colour, thus they are swapping equal value cards. There's also the possible tactic of swapping the original colour back to the player.
xaviergisz, Mar 02 2018

       //You can get round that by not allowing anyone to refuse a game//   

       This would be too hard to enforce. Players would hide, go on long toilet breaks, etc.
xaviergisz, Mar 02 2018

       I wonder if game play would become too chaotic if a limited number of third, neutral colors were added into the mix.
RayfordSteele, Mar 02 2018

       //too chaotic//   

       I understand each of those words, but the phrase eludes me.
Voice, Mar 02 2018

       Ie. left open to too much chance and not enough strategy.
RayfordSteele, Mar 02 2018

       Here's a way to make this less chaotic and ensure that everyone plays without having multiple colors. Have everyone standing in two long rows facing each other. The players play one round against the person opposite them, then shift to the right half a body width to play the next opponent. When someone gets to the end of one row, they rotate around onto the other row (taking one turn with no opponent). End the game when every player has played every other player. Alternately, keep playing, having people drop out when they are out of cards until there is one winner. The rules should make it easy to see the plays of the people nearby so people can make some guess about each competitor.   

       With this arrangement, the game might run smoother/quicker using something like marbles instead of cards. Each player reaches into their opaque bag and grabs one or two. They hold their hands out and open them palm up at the same time. That would be easier to see at a distance with objects that can't be stacked. Have discard buckets easily reachable.   

       [+] This seems like it could be very interesting and fun. Be sure to let everyone know how this works a the scout camp.
scad mientist, Mar 04 2018

       This game was played at a scout camp. It was moderately successful. The problem was some of the scouts weren't interested and just gave their cards away (which is against the rules).   

       To prevent people just giving cards away, cards of the original colour should be worth some points (e.g. half of value of other cards). This would mean if you don't want to play, but still want to win points (because of incentives such as minor prizes), you could just hold onto to your original cards and return them at the end.
xaviergisz, Mar 25 2018

       What no alliances between players A & B to mug C in the urinals to steal his cards while D acts as look out then splitting them? I'm shocked, clearly scouting isn't what it used to be, kids must have just changed since my day (or were there just no prizes this time around?)
Skewed, Mar 26 2018

       It was an outdoor night activity on a large camp (300+ scouts). They were all competing for points (accumulated over many activities throughout the weekend); the winner taking home perpetual trophy.   

       I called the game "swap, steal or discard" which was probably a mistake. After the game had finished I had a few scouts express surprise that they weren't allowed just to steal people's cards, and that consequently they were disqualified.
xaviergisz, Mar 26 2018


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