1. The Objective
Moon is a trick-taking game played with dominoes instead of cards. Each hand, one team bids how many of the seven tricks it can take, then tries to make that bid while the other team tries to stop it.
The first team to reach the target score — 250 points by default — wins the match. A successful Moon bid wins it on the spot.
2. The Table
- Players: four, in two partnerships. Partners sit across from each other: you and Jules against Rowan and Avery.
- Tiles: a double-six set. All 28 tiles are dealt, seven to each player, with nothing left over.
- Dealer: picked at random for the first hand, then passes to the left each hand.
3. Bidding
Bidding starts left of the dealer and goes around the table once. Each player either passes or bids the number of tricks their team promises to take.
- Bids run 3, 4, 5, 6, 7, then Moon: all seven tricks, with the game riding on it.
- Every bid must be higher than the one before it. A Moon bid ends the bidding at once.
- If all four players pass, the tiles are shuffled and dealt again.
The highest bidder's team becomes the bidding team; the other team are the defenders.
4. Calling Trumps
The winning bidder names the trump suit. There are two kinds of call:
A number, blanks to sixes
Every tile showing that number becomes a trump and belongs only to the trump suit. The double ranks highest, then the tile paired with six, then five, and on down. With fives as trumps, the order is 5–5, 5–6, 5–4, 5–3, 5–2, 5–1, 5–0.
Doubles
The seven doubles become the trump suit, from 6–6 down to 0–0, and they no longer belong to any number suit.
5. Playing the Tricks
The bidder leads the first trick. Whoever wins a trick leads the next one.
What suit a tile leads
- A trump leads trumps.
- A double that isn't trump leads its own number.
- Any other tile leads its higher number: a 5–3 leads fives.
Following suit
You must follow suit if you can. A tile like 5–3 can follow either fives or threes, but never trumps unless it is one. If trumps are led, you must play a trump if you have one. If you can't follow, you may play any tile, including a trump.
Who wins the trick
The highest trump played wins. If no trump was played, the highest tile of the suit led wins. A tile that didn't follow suit and isn't a trump can never win.
6. Scoring
- Bid made: 10 points per trick bid, plus 1 for each extra trick. Bid four and take five, and you score 41.
- Bid missed: minus 10 points per trick bid. Scores can drop below zero.
- Defenders score nothing — their job is to set the bidders.
- Moon made wins the game. Moon missed loses it.
Winning the match
The first team to reach the target wins. The default is 250, with 500 as a longer choice, or set any target you like.
7. House Rules & Options
Moon's rules vary from table to table. Don Dominoes plays Don's house rules by default, and you can switch on common variants under New game → House rules:
- Lowest bid of four instead of three.
- "Follow me" — no trumps; the tile led sets the suit.
- Forced dealer bid — if everyone else passes, the dealer must bid instead of redealing.
- Gentler missed Moon — lose 70 points instead of the game.
- Classic scoring — both teams score a point per trick, a missed bid loses the bid, a Moon is worth 21, and the first to 21 wins.
8. Strategy Tips
- Count your sure tricks before bidding. High doubles and the top tiles of a strong suit are your tricks; your partner usually adds one or two more.
- Call your longest suit. Four or more tiles of one number, especially with its double, make it a strong trump call.
- Pull trumps early. As the bidder, leading your top trumps clears them out of the defenders' hands so your other winners stay safe.
- Don't overtake your partner. If your partner is already winning the trick, play low and save your big tiles.
- Win cheaply. When you need the trick, take it with the smallest tile that will do.
- Keep count. Track which trumps and doubles have fallen, so you know when your tiles become the highest left.
- Only shoot the moon with a near-lock. One lost trick costs the whole game.
9. Questions
What is Moon dominoes?
Moon is a trick-taking domino game from Texas, a close cousin of 42. Players bid on how many of the seven tricks their team can take, the winning bidder names trumps, and teams try to make or stop the bid.
How many players does Moon need?
Moon on Don Dominoes is played by four players in two partnerships, with partners sitting across from each other. Classic Texas Moon is a three-player game with a widow; it isn't built here yet.
What does it mean to shoot the moon?
Shooting the moon is a bid to take all seven tricks. In Don Dominoes' house rules, making it wins the game on the spot, and missing it loses the game.
Do you have to follow suit in Moon?
Yes. If you can follow the suit that was led, you must. If trumps are led, you must play a trump if you have one. Only when you can't follow may you play any tile.
How is Moon scored?
With the house rules, a team that makes its bid scores 10 points per trick bid plus 1 for each extra trick. A missed bid loses 10 points per trick bid. Defenders score nothing. The first team to 250 wins.
How does Moon differ from 42?
Moon on Don Dominoes uses all 28 tiles with no count dominoes: every trick is worth the same, and the bidding is about tricks rather than points. Moon also adds the all-or-nothing Moon bid.