Last updated: 30th January 2023

This is a complete set of rules for the card game Moo, a variant of the rule-changing card game known as Mao.

• FAQ

100. Moo is a game for 3 or more players.
101. Moo is played with one or more decks of standard playing cards, including jokers. If many people are playing, using multiple decks is recommended to ensure a good stock of cards. Decks do not need to have the same back or face design.
102. At least one player needs to know the rules of Moo.

200. A player who knows the rules of Moo should start the game by taking the following steps:
     • Shuffle all cards and place them face-down to create the draw pile.
     • Deal out 5 face-down cards to each player for their starting hands.
     • Formally announce the start of the game. Here is an example opening preamble:

       "We are now playing the game of Moo. In this game, all rules are secret, except for these three: Players take turns in a clockwise direction, you may pick up a card if you cannot play, and the Joker is the 9 of Diamonds."

     • Take a card from the draw pile and lay it face up to start the play pile.

300. Players take turns, starting with the player on the dealer's left and continuing in a clockwise order.
301. To complete their turn, a player must:
     • Either play a valid card face-up to the play pile, or draw one card from the draw pile.
     • Take all other actions required of them on their turn, if any.
302. A card is valid if it has the same rank or suit as the last played card. If a player plays a card that is not valid, they may be penalized with the penalty call "Bad card".
303. If a player has no cards remaining in their hand, and has no remaining actions left to perform, and has not committed any infractions for which they could be penalized, they must say "Moo" to earn one Moo Token, and leave the game. If they fail to say "Moo", they may be penalized with the penalty call "Failure to say the name of the Great Bovine Deity".
304. A player may voluntarily donate a Moo Token to another player.
305. If the draw pile is exhausted, take all but the top card of the play pile, turn those cards face-down, and shuffle them. Those cards become the new draw pile.

400. People who are not in the game may join (or rejoin) the game at any time, by dealing themselves 5 cards from the draw pile.
401. People who are not in the game are not bound by the rules of Moo and cannot be penalized.
402. Players who left the game still retain any Moo Tokens they earned during that game.
403. Players may voluntarily leave the game at any time. If they do, they must abandon their card hand. The hand should be shuffled back into the draw pile.

500. If a player plays an Ace, the next player's turn is skipped.
501. If a player plays a 7, they must say "Have a nice day". On the next player's turn, instead of playing/drawing a card as usual, that player must either say "Thank you" and draw a card, or they may also play a 7 and say "Have a very nice day", in which case the next player must either say "Thank you very much" and draw 2 cards, or also play a 7. This loop repeats for as long as subsequent players are able to play 7s, with the number of "very"s and the number of cards drawn increasing by one each time.
502. If a player plays an 8, the turn order is reversed.
503. If a Jack is played, any player may call out the name of a suit. The next card played must either be of the called suit, or another Jack.
504. If a player plays a Spade, they must say the name of the card they played (eg. "4 of Spades").
505. If a player plays the 9 of Diamonds, they must say "That's the badger".
506. Playing a Joker is considered to be equivalent to playing a 9 of Diamonds.

600. If a player breaks a rule, any player may give them a penalty by saying the formal penalty call that corresponds to the infraction committed, and giving the offending player one face-down card from the draw pile. In these rules, the term "penalize" is equivalent to this penalty action.
     • 600.1. Players cannot be penalized more than once for the same instance of an infraction.
     • 600.2. If a single action by a player breaks multiple rules at the same time, they may be given separate penalties for each rule broken.
     • 600.3. Penalties must be issued within a short time of the infraction.
     • 600.4. Players may penalize their own infractions.
601. If a player calls an invalid penalty, they may be penalized, with the penalty call "Bad call". The penalty they were going to give is voided.
602. If a penalty is voided or revoked, return any penalty cards that resulted from the penalty to the draw pile face down, shuffling the draw pile if necessary.
603. If a rule says that a player must do something, and they do not do it, they may be penalized. The rule may provide a specific penalty call to be used. If it does not, the general call "Failure to (X)" can be used instead, where (X) is the thing they did not do.
604. If a player was penalized for failing to do something, and they continue to fail to do it, they may be penalized again with a penalty call of the form "Repeated failure to (X)". The penalty may be repeated until they take the required action. This only applies for as long as it is still legal for them to take that action.
605. If a rule requires a player to take an action, the player must be given a feasible amount of time to do so.
606. If multiple rules require actions to be taken simultaneously, the player may choose the order in which they take those actions, with the exception of saying "Moo" to earn a Moo Token, which must be the last action taken before leaving the game.

700. If a player has any Moo Tokens, they may spend one and say "Introducing new rule" to add a new secret rule to the game. If necessary, the player should also invent an appropriate penalty call for players who break it. New rules may amend existing rules.
701. If a new rule conflicts with an existing rule, the new rule takes precedence.
702. If a rule is invalid, it is considered void and players do not have to follow it.
     • 702.1. If a rule would not be applicable to all players equally once everyone has full knowledge of the rule, it is invalid.
     • 702.2. If a rule is not deducible, either from observation or from information provided in the penalty call, it is invalid.

800. If a player says "Point of Order" and a Point of Order is not currently in progress, a Point of Order is started.
801. Players must put down their cards at the start of a Point of Order, and must not touch them while the Point of Order is in progress. If they do, they may be penalized with the penalty call "Touching cards during a P of O".
802. During a Point of Order, normal gameplay is suspended. Players cannot play cards, the turn order does not advance, and the time limit for playing cards does not apply. All other rules remain in effect.
803. Players must not say "Point of Order" during a Point of Order, other than when making the call to end it. If they do, they may be penalized with the penalty call "Saying P of O in a P of O".
804. Players may propose a vote in a Point of Order. Votes may be used to change any aspect of the game, including amending or removing rules and reversing penalty decisions. If a majority of players agree, the vote passes and the game changes accordingly.
805. To end a Point of Order, any player may say "End of Point of Order". Gameplay resumes from where it was stopped.
     • 805.1. The 10 second turn timer is restarted when resuming play after a Point of Order.

900. On a player's turn, if they do not play a card or pick up a card from the draw pile within 10 seconds, they may be penalized. The penalty call for this is "Failure to play within 10 seconds".
901. If a player plays a card when it is not their turn, they may be penalized with the penalty call "Playing out of turn". Their play is not considered valid. They must take back any cards that they played.
902. If a player has only one card remaining in their hand, they must say "Last card".
903. If a player says "Moo" at any time other than when starting the game or when correctly doing so to earn a Moo Token, they may be penalized with the penalty call "Taking the name of the Great Bovine Deity in vain". For this and only this infraction, the penalty is 3 cards instead of the usual 1.
904. If a player says something which is untrue, they may be penalized with the penalty call "Lying". This applies even if the untruth is unintentional.
905. If a player performs an action which is considered unsporting, they may be penalized with the penalty call "Unsporting conduct". Players may use their own discretion to decide what is unsporting.
906. If a player performs an action which is considered to be cheating, they may be penalized with the penalty call "Cheating". In addition to the definitions of cheating provided in these rules, players may use their own discretion to to decide what is cheating.
     • 906.1. Discarding or removing a card from one's hand in any way not permitted by the rules, is cheating.
     • 906.2. Reordering the play pile is cheating.
     • 906.3. Peeking at or manipulating another player's hand cards without their consent is cheating.