Rules

Dominoes has as many rulebooks as it has kitchen tables. Here is what this one does — the same text the app shows on its own Rules screen.

Dominoes has no single rulebook, and this page does not pretend otherwise. What follows is how the game plays out of the box and, beside each part, the agreement that changes it. Everything named in italics is a switch in Settings → Agreements.

The set and the deal

A double-six set: 28 tiles, every pair of numbers from 0:0 to 6:6, each exactly once. Two, three or four players take seven tiles apiece. At four, that is the whole set and there is nothing left over; at two or three, the rest is the boneyard to draw from.

Tiles dealt and number of players are both agreements. So is whether there is a boneyard at all — a four-handed game with no boneyard is the ordinary one, and a two-handed game without it is a short, sharp variant where you play what you were given.

Who opens

By default the lowest double on the table opens the round — 0:0 if anybody holds it, otherwise 1:1, and so on. If nobody has a double at all, the game falls back to the heaviest tile.

Opening rule also offers: the highest double, a named double (Kozyol uses 1:1), the heaviest tile, any tile at all, the previous round's winner, or a rotation by the day of the week. Each has a fallback for the deals where it cannot be applied.

Playing

Turns go round to the left. On your turn you add one tile to one open end of the board, matching the number that end shows: a 4:2 can go on an end showing a four or an end showing a two. The number on the other half becomes the new open end.

A double is normally laid across the chain rather than along it. It is not just decoration: it is how you can tell at a glance that the end is a double, and in some rule sets it is what opens further arms.

If you cannot go

With a boneyard, you draw. By default you draw until you can play; the alternatives are one tile and then pass, or drawing being entirely up to you. Two more switches decide whether the very last tile in the boneyard may be taken, and whether you may buy tiles while you already have a legal move.

With no boneyard — or with an empty one — you pass, and the game moves on. Consecutive passes all the way round the table mean nobody can go.

How a round ends

Two ways:

Domino. Somebody plays their last tile. The round stops there.
Blocked — ryba, "the fish". Nobody can go and there is nothing left to

draw. Everybody is stuck holding tiles.

A blocked round normally counts. A blocked round counts can be switched off, in which case the deal is thrown away and dealt again — but only if there is a boneyard, or the same hands would come back forever.

Scoring

By default the losers count the pips left in their hands and record them against themselves. The winner records nothing. Over a match those totals climb, and the target decides what reaching it means.

When a round is blocked, the default is that the player with the fewest pips collects everybody else's. The alternatives are the difference and the whole total to the worst hand.

Who records what	Losers take their own pips · only the worst hand records · the leader collects · free ends in multiples of five · pips of the tile played
A blocked round	Fewest pips collects · the difference · the whole total to the loser
Round scores to	Round each round's score to the nearest 5 or 10, as some tables do
Minimum to start recording	Kozyol's rule: nothing under 13 goes on the board
The target	Reaching it loses (the classic) · reaching it wins · or play a fixed number of deals

The shape of the board

Where the chain is allowed to grow is the biggest single difference between one game of dominoes and another.

One line	A single chain with two ends. It folds when it runs out of room, but it is still one chain.
Cross (Osyol)	The line runs both ways from the first double; once each side has taken its tiles, two more arms open off the spinner and the board has four ends.
House (Telefon)	All four arms open immediately off the opening double. No waiting.
Trains	A train for each player and one for the table. You feed your own and the communal one; the moment you cannot go, yours is thrown open to everybody until you come back to it.

Kozyol

The variant most people mean by "dominoes" in Russian-speaking countries, and the one the game starts with. Four players in two pairs, sitting opposite each other. The whole set is dealt, so there is no boneyard and being stuck means passing. 1:1 opens. Nothing under 13 points is recorded. The pair that reaches 101 is the goat.

Because the sides are pairs, the scores are kept as us and them rather than per seat — and playing a tile that strands your partner counts as your own mistake.

The old ceremonies

Kozyol collected traditions, and they are switches too:

General — close on the boar (6:6), or win having laid both key doubles

yourself, and you are the General.

Admiral — the match closes on both key doubles one after the other. The

loser is no longer the goat but the Admiral.

Snotty goat — the match closes on the blank. The loser becomes the snotty

goat, unless an Admiral finish outranks it.

The winner goes back to zero — after a finish like that, the winner's score

is wiped.

The other agreements

A handful more that do not belong to any one variant:

Doubles lie across — off, and a double is laid in line like anything else.
Two doubles in a turn — if you can lay two doubles at once, you may. There

is a Skip button when you would rather not.

A double may close an arm — Osyol's rule: a double nobody can cover shuts

that arm for good.

Extra turn when the ends add up to and draw two when the ends add up to —

Semyorka's rules, where the sum of the open ends decides what happens next.

Tiles before the cross opens — how much of the line has to be built before

the sides unlock.

The editor checks combinations as you make them. Two rules that cannot both be true are named on the spot and the set will not save; a rule that has no effect in the game you have built is greyed out with a note saying why.