Dominoes rules and strategy: Block, Draw, Muggins and Latin teams

01The tiles and the goal

A domino is a tile divided into two halves, and each half shows a number of pips from 0 (blank) up to 6 in the standard double-six set. There is one tile for every pair of numbers, so the set has 28 tiles: seven doubles, such as 6-6 and 0-0, and 21 mixed tiles, such as 6-4 or 3-1. A bigger double-nine set has 55 tiles and is used for larger tables or longer games. Every number appears on seven tiles in the double-six set (ten in double-nine), a fact that drives most of the strategy.

The goal is to be the first to play every tile in your hand. You do that by adding tiles to a growing chain. Each new tile must match the number at one of the two open ends of the chain. When a hand ends, the winner scores points from the tiles that are left in the other hands, and the first player or team to reach the target, usually 100, 150 or 200 points, wins the match. Play dominoes online in your browser to follow along as you read.

02Setting up a hand

Shuffle the tiles face down and give each player 7 tiles in a double-six game, keeping them hidden from the others. Two players leave 14 tiles face down and three players leave 7. In the draw game that remaining pile is the boneyard. With four players and 7 tiles each, every tile is dealt and there is no boneyard, which is why four-player games are usually Block games.

The first hand of a match is opened by the player holding the highest double, who must play it. If nobody holds a double, the heaviest tile (most pips) opens. In later hands the winner of the previous hand opens with any tile they like. If the previous hand was a tied block, the opening moves to the next player.

• Double-six: 28 tiles, 7 each, usually Block or Draw.
• Double-nine: 55 tiles, 12 each for 2 or 3 players or 10 each for 4 in Block, fewer in Draw.
• Highest double starts the first hand. Winner of the last hand starts the next.
• Chain grows at both ends from the first tile.

03How a turn works

Play moves around the table. On your turn you choose a tile from your hand that has a half matching the number at one end of the chain, and you place it with the matching half touching that end. The other half of your tile becomes the new open end. A double matches only its own number, and it exposes that same number again at the end, which is why doubles can be awkward later in the game. On a phone you tap the tile and then the glowing end, or drag the tile onto the end.

If you have no matching tile, what happens depends on the game. In the Block game you pass. In the Draw game you draw tiles from the boneyard one at a time until you find one you can play. If the boneyard is empty and you still cannot play, you pass.

04Block dominoes and tranque

Block dominoes has no drawing, so the tiles each player holds are all that exists in the game for them. That makes it a game of memory and inference. Because every tile is dealt in a four-player game, when you see which numbers are being played you can work out exactly what the others hold. A game that ends when nobody can move is called a block, and in Spanish a tranque.

When a hand is blocked, each player adds the pips in their hand. The lowest total wins the block. The winner then scores the pips in the other hands (some groups use the difference, and some give the winner all pips including their own; the common Latin American rule is to score the opponents' pips). If two players tie for the lightest hand, the block is a draw and nobody scores. Block is the standard game in Cuba, the Dominican Republic and Puerto Rico, usually in teams of two.

05Draw dominoes and the boneyard

In the draw game you may not pass while there are tiles in the boneyard. If you cannot play, you take one tile at a time until you can. Doing this changes the game in two ways. It gets rid of dead hands, where you sit with no plays for many turns. And it hides information, because you do not know what the boneyard holds, only that it contains every tile not in your hand and not on the table.

Drawing is also a cost. Every tile you draw adds pips to your hand and gives your opponent more information about what you lack. A player who is forced to draw often ends up with an awkward, heavy hand. Draw is the best way to learn the basics because it is more forgiving of mistakes.

06Muggins and All Fives: scoring while you play

Muggins adds a second scoring system. After you play a tile, add the numbers at the two open ends. A double at an end counts both of its halves, so a 5-5 at the end of the chain counts as 10. If the total is divisible by 5, you score that number of points straight away. For example, after you play 6-4 so that one end is 4 and the other end is 6, the total is 10 and you score 10.

At the end of the hand the winner collects the pips in the opponents' hands, rounded to the nearest 5. A match to 100 with Muggins scoring is quick, because a good player takes 10s and 15s along the way. The strategy is different from plain pip counting: you play to make totals of 5, 10, 15, 20, 25 and 30, and you try not to leave your opponent an end total that is divisible by 5. Count the ends before every move.

• Open totals: 5, 10, 15, 20, 25 and 30 score for the player who made them.
• Doubles at an end count twice, so 5-5 gives 10, 6-6 gives 12, 3-3 gives 6.
• A play that scores nothing but leaves a safe total can be better than a small score that gives the opponent a big one.

07Playing in teams of two (Latin style)

In many countries dominoes is a partnership game for four. You sit across from your partner and take turns clockwise. You and your partner share a score and cooperate without speaking: the only information you may use is what happens on the table. When a team goes out, it scores the pips left in the other team's hands. If the hand is blocked, the teams compare the combined pips in both hands and the lighter team wins.

Partner play adds new ideas. If your partner passes, they hold no tiles of the numbers at the ends, so you should not rely on them there. If your partner plays a number and the next player passes on it, your partner may be signalling a strong suit. A partner who opens a number tends to hold more of it, so supporting their number when you can is usually right. Do not block your partner by closing a number they have been building. In PlayNest you can play a four-player game with a friend as your partner and computers in the other seats.

08Core strategy: count, read and plan

Count numbers. Each number appears on seven tiles in a double-six set. When you hold four of a number and three have been played, you know the last one is yours. When you hold none and six have been played, you know nobody has that number except possibly one player. Counting tells you when it is safe to leave a number at the end of the chain: if nobody else holds it, your opponents will be stuck.

Read the passes. A pass means the player has none of the numbers at the ends. That is a hard fact for the rest of the hand (in the draw game, after the boneyard is empty). If your opponent passes on a 4 and you can leave a 4 open, they cannot play again until the end changes. If your partner passes, avoid leaving that number if you can.

Plan the block. A block is a weapon when your hand is light. If you hold the last few tiles of a number and the rest of the hand is low pips, closing the board wins the hand even though you did not go out. When your hand is heavy, do the opposite: keep several numbers open, and play your biggest tiles first.

• Play doubles early. They can only go on their own number.
• Keep a spread of numbers. A flexible hand always has a move.
• Hold on to a number you control, and keep its tiles for the end of the hand.
• Do not open a new number if you can play on a number the opponent has passed on.
• In Draw, count the boneyard before choosing whether to force a block.

09How the computer decides

The Easy computer plays any legal tile. Normal uses a heuristic: it prefers heavier tiles and doubles, keeps numbers it can follow, scores in Muggins, and remembers passes. Hard uses determinization, a technique for games with hidden information. It writes down which tiles it cannot see, removes numbers a player has passed on, deals the rest at random to the hidden hands, and plays each possible move out to the end of the hand in a large number of imagined worlds. It chooses the move that does best on average. Because the sampled worlds obey the passes, Hard plays as if it were reading the table.

Use the Hint button to see what Hard would play and compare it with your own choice. You will often see it keep a number open that an opponent cannot answer.

10Common mistakes and how to avoid them

The first mistake is holding on to doubles. A double is easy to play early and nearly impossible later. The second is opening many numbers, which gives opponents more places to play. The third is ignoring passes: a pass is the best information the game gives you. The fourth is playing the highest tile every time without thinking about the ends. Heavy tiles are good to dump, but not if they leave your opponent a free play.

In Muggins, the biggest mistake is forgetting to count the ends. Every move changes the total, and giving the opponent a total of 10 or 15 is expensive. If you are not sure, play the tile that leaves a total like 7, 8, 9 or 11, which score nothing for anyone.

11Try it: a short plan for your first match

Start with Draw, double-six, two players against the Easy computer and a target of 100. Practice matching and notice when you are forced to draw. Then move to Block against Normal and watch the chain close. Add Muggins scoring when counting the ends feels natural. When you are comfortable, try four players in teams of two, first with computers and then with friends. You can learn more tile-and-memory skills from our Scopa guide, and the logic habit of ruling out possibilities is the same one used in Mastermind.