Mao (or Mau) is a card game of the shedding family. The aim is to get rid of all of the cards in hand without breaking certain unspoken rules which tend to vary by venue. The game is from a subset of the Stops family and is similar in structure to the card game Uno or Crazy Eights.
The game forbids its players from explaining the rules, and new players are often informed that "the only rule you may be told is this one". The ultimate goal of the game is to be the first player to get rid of all the cards in their hand. Specifics are discovered through trial and error. A player who breaks a rule is penalized by being given an additional card from the deck. The person giving the penalty must state what the incorrect action was, without explaining the rule that was broken.
There are many variants of Mao in existence. While beginners sometimes assume that the dealer (sometimes called the "Chairman", the "Mao" or the "Grand Master") and other experienced players are simply making up possibly inconsistent rules (as in the games Mornington Crescent or Fizbin), the rules of Mao are consistent within each game and can be followed correctly.
History
Mao is most likely descended from the German game Mau Mau. It may have influenced the game Eleusis, which was published in Martin Gardner's column in Scientific American in June 1959. Both of these games share similar principles of inductive reasoning.
Other inductive games in which not all players know the rules include Penultima and Zendo; however, the secret rules in those games are made up at the start of play and disclosed at the end of each round, and the scope and subject matter of Eleusis, Penultima or Zendo rules may be more explicit and closely circumscribed.
Mao's name and rules are a reference to Chairman Mao Zedong's rule over China. The rules not being explained are an allusion to the laws in China at the time being in constant flux, leading to many people being arrested for laws they did not know existed.
Rules
Part of the traditional experience of Mao is a new player being forced to learn some or all of the rules of the game through observation and trial and error. Thus new players are not presented with a list of rules, as part of the game is to discover the rules through gameplay.
The exact set of rules divulged to new players varies between groups of players: some groups will say "the only rule I can tell you is this one", others will reveal the goal of eliminating cards, and some might outline the basic rules and, in most cases, no rules are revealed at all. However much information is revealed, the players will explain that they are not allowed to reveal any more, and that the new player must deduce the full rules during play.
Mao rules can vary widely between different groups with no individual set of rules being canonical.
Rules of play
Each player is dealt an initial hand of the same number of cards; the exact number of cards dealt varies, but is generally either three or seven. The size of the deck also varies; it is good to have approximately one 52-card deck for every two or three players, but missing or extra cards are not important to gameplay. Two or more combined decks is common; matching card backs is not important. Once the cards are dealt, the remaining cards are placed face down in a stack in the middle of the table, and the top card from the stack is turned over and placed next to it.
The rules are typically changed between games, either at the beginning or with each successive game. Many times, this is simply that the winner of the last game is allowed to construct their own rule. This new rule is made known to the dealer or not, depending on the game, though in many varieties it is required for the dealer to know the rule in order to confirm its use and to enforce it. Often the winner of the last game is also made the new dealer.
In another variant, players abandon all normal rules and have each player make up a rule of their own at the very beginning of the game. This variant is known as "Dutch Mao", or "The People's Democratic Dictatorship", and probably several other names. It has no restrictions on what cards to play (other than those made by the players) and can get very confusing when rules conflict.
Speaking
Many of the rules of Mao involve speech. Mostly this means that the right thing must be said at the right time. Saying the wrong thing, or speaking at the wrong time, will usually incur a penalty.
;No talking
:In most variants of Mao, no unnecessary speech is allowed, and one may only speak when required to do so by the rules. For example, if one plays a 6 of spades (with the declaring spades rule active), one is required to say "six of spades" and will be penalized for not doing so. But if one says, "six of spades, I didn't forget this time" one will be penalized for the additional unnecessary speech. A different but common way to say this is "excessive verbosity".
;Point of order
:Any player (or, in some variations, only the dealer) may at any time announce "point of order", Usually a player is given a reasonable amount of time to say "thank you" before being penalized. Failure to say "thank you" after a penalty card will usually result in another penalty card. One "thank you" will usually cover for all occurrences where it was required.
;Last card
:Some variants require the player to announce when they have only one card left in their hand.