Written by Howard Fosdick ©

Overview: Moon is a domino game in which you play dominoes to tricks, much like many card games. It's usually considered part of the 42 family of domino games, but it’s really a bit different because each trick won is valued at 1 point.

Players: Moon is for three players. It's often played by 42 enthusiasts when they don't have a fourth. (There's also a four-player partnership version we'll describe after the three-player game.)

Equipment: Take a 6-6 set of dominoes, and remove all tiles with blanks on them. This leaves the 21 tiles with which you play Moon.

The Suits: Moon uses the same suit system as 42, except that there are no blanks:

‹––high    Members    low––›
6-6  6-5  6-4  6-3  6-2  6-1
5-5  5-6  5-4  5-3  5-2  5-1
4-4  4-6  4-5  4-3  4-2  4-1
3-3  3-6  3-5  3-4  3-2  3-1
2-2  2-6  2-5  2-4  2-3  2-1
1-1  1-6  1-5  1-4  1-3  1-2
6-6  5-5  4-4  3-3  2-2  1-1

Each tile with two different numbers on its face is a member of the two suits on its face. Note that the doublets rank highest in each of these suits.

Doubles are members of the single suit number on their face, and also the "doubles suit".

Deal: Each of the three players takes 7 tiles.

Bidding: Starting to the left of the dealer, each player has one chance to either bid or pass. A bid is a contract to win at least the specified number of tricks. The highest bidder becomes the bid winner.

Bidding starts at 4 and can go as high as 7 (since each trick counts for 1 point and there will be 7 tricks played). Each bid must be higher than the previous one. You can also bid 21 for Game. A bid to take all tricks is called shooting the moon.

Prior to leading to the first trick, the bid winner announces the trump suit. The trump suit can be any of:

  • Any of the 7 suits listed in the above table -- including Doubles
  • No trump (which is commonly called "follow me")

Play: Rules of trick-play are the same as in 42. That is, if a trump is led, all players must follow with a trump if they can. If any non-trump tile is led, the higher number on each tile declares its suit, and all players are required to follow that suit if they can.

If a player can not follow suit, he is free to play any domino.

A trick is won by the highest trump, if any trumps were played to the trick. Otherwise, the trick is won by the highest tile of the suit led.

The Trump Suit: Once a suit has been declared as trump, any tile with that number on it is considered only a member of the trump suit!

For example, if 2's are declared trump, all tiles with 2's on them are only members of the trump suit for that deal. This means that if a player leads a 6-4 tile, and you have the 2-6 tile, you do not have to follow suit with your 2-6 tile, because that's a member of the trump suit for the deal -- it's not at all a member of the 6's suit.

Scoring: If the bidder makes his bid or more, he scores his bid. He does not score any extra for tricks he may have won above his bid.

If the bid winner does not make his bid, he is "set" and subtracts the bid from his score.

Each opponent always scores the number of tricks he or she takes.

Winning Game: Game is won by the first player to 21 points. Note that a bid of Game can win the Game in one deal, if the bid winner succeeds. (If he fails, he scores -21 points.)

Variations: You'll often see folks play with 22 tiles total, instead of 21. The extra tile is the 0-0. This tile is essentially "suitless" unless Doubles are declared as trump, in which case it ranks as the lowest in that suit.

When playing with 22 tiles, deal 7 to each player, and leave the last domino face-down as the widow. It is the bid winner's privilege to pick up the widow and decide whether he wants to discards some other tile from his hand to keep it. He does this prior to naming the trump suit.

As with 42, some prefer to score in "marks" rather than points. If the bidder wins he scores one mark. If the bid winner fails, his two opponents score one mark each. The first player to reach 7 marks wins Game.

Tips for Play: Moon differs from 42 in that there are no valuable counter tiles and all tricks are worth 1 point each. The two players opposing the bid winner form a natural, temporary alliance for the hand.

The purpose to winning the bid is to drive the hand by your leads that force suit control on your opponents. The same hand can be powerful or weak depending on the suits the tricks are played in.

Only bid Game if you're quite confident you can win all the tricks. Otherwise, you could end up with a negative score.


Partnership Moon

Moon can also be played by four players in two opposing partnerships. Use the full double six dominoes set, and deal 7 tiles to each player. Four tricks is the lowest permissible bid.

If the partnership that wins the bid makes their bid, they win the hand and score points for all the tricks they took. If they fail to make their bid, they score minus the amount of their bid. Note that scores can go negative on losing bids. The players opposing the bidders always score the number of tricks they take.

The first partnership to 21 points wins the game. Best of three games wins the match.

Sources: These rules were compiled from personal play, then cross-checked with numerous sources on the internet. I don't know that there is a single authoritative source for Moon rules, though the webpage at probably comes closest. You might also like to read our article on all domino trick-taking games.

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License: Feel free to print, copy, and distribute these rules, so long as you retain this paragraph. Written by Howard Fosdick © 2023, distributed under Creative Commons License BY-ND.      HOME