Dominoes: a double-six table you can play one-thumbed on a phone

01  What it is

This is one-on-one dominoes on a standard double-six set: twenty-eight tiles, one for every pairing of two numbers from blank to six. You and the computer take seven each and the remaining fourteen go face down in the boneyard. You play tile for tile until one of you empties a hand, or until the game locks up with neither side able to move. The first to a hundred points wins the match, and a match is however many hands that takes.

The opening is fixed rather than chosen: whoever holds the heaviest double lays it and the other player moves first. If neither hand holds a double, the heaviest tile by pip count opens the line instead. After that you are matching the two open ends of the line, and that is the whole game.

It runs entirely in your browser, on a phone in portrait or on a desktop, with no account and nothing to install. Playable tiles are highlighted and each one is a real button, so tapping and the keyboard both work; if a tile fits only one end it goes there immediately, and if it fits both ends they glow and you pick. There is no undo and no hint button, which is the one place the app is deliberately unhelpful: a mis-tap costs you what it would cost you at a table.

02  Three rule sets that play nothing alike

The menu offers Block, Draw and All Fives, and the difference is what happens when you cannot move. In Block you simply pass, and the hand carries on. In Draw and All Fives you take tiles from the boneyard until you have something playable, or until it runs dry and only then do you pass. Draw games run longer and turn, honestly, on the luck of the draw.

Two passes in a row ends the hand. Nobody can move, so the player holding the lighter hand wins it — and takes the loser's entire pip total as points, not the difference. If the two hands are exactly equal on pips the hand is a tie and nobody scores. Going out instead of being blocked is worth the same thing: you score every pip left in the opponent's hand.

That one rule is why heavy tiles matter so much more than they look. A six-six stranded in your hand is twelve points handed over the moment the board locks. The line of play is also straight — you cannot branch a new arm off a double the way many people do at home. Two ends are live at any moment, ever, which makes the game tighter and more calculable than tabletop dominoes with a spinner.

03  All Fives is the one worth learning

All Fives keeps the same tiles and the same hands but moves the scoring inside the hand. After every tile laid, add the two open ends of the line together. If that total is a multiple of five, the player who just laid the tile banks it on the spot — an eleven is nothing, a fifteen is fifteen points right now. A brass counter under the line shows the running total and lights up when it is worth something.

Two details decide most of the points. A double lying at an end counts both of its halves, so a six-six sitting on the end is twelve, not six — and the moment another tile is laid on top of it, it is buried and counts for nothing. And the opening tile has both of its own faces showing, so a hand that opens with five-five or six-four starts ten points up.

End-of-hand scoring is rounded to the nearest five to match. Go out and you take the opponent's pips rounded — thirteen pays fifteen, twelve pays ten. If the hand locks up instead you only score the difference between the two hands, rounded the same way, so a close lock can genuinely be worth zero. Because counts land mid-hand, the match can also end in a way that surprises people: you can cross a hundred while losing the hand you are playing, and the scoreboard decides the match, not the last hand.

04  The Hard opponent is a formula you can read

Both difficulties only ever pick from the moves that are actually legal, and neither is random — ties are broken by the lowest pip count, then by tile, then by end. Easy is a greedy unloader: it plays its heaviest legal tile every turn, with no memory of anything.

Hard scores every legal move and takes the best. Shedding pips is worth a point per pip, so heavy tiles still go first. Playing a double adds three, because doubles only ever match one number and are dead weight late. Keeping tiles that match the new open ends adds half a point each. And laying a tile that leaves both ends on numbers you have already passed on — numbers it knows are dead in your hand — is worth four, the heaviest term in the formula and the one that actually beats people.

That memory is built only from your passes. Anytime you pass, the AI records both open-end numbers as voids for you and never forgets them for the rest of the hand. In Block that is airtight, because you cannot gain tiles. In Draw and All Fives it can go stale, because you can draw and later play a number the AI has written off — a small but real hole you can lean on. What it does not do is model which numbers are likely still live across the whole board; that term exists in its spec at weight zero. It remembers your passes and nothing else, so passing is not free information-wise even when it costs you nothing on the board.

05  Winning, the streak, and the card

Winning a match extends a win streak kept in your own browser and shown on the menu, so it is still there tomorrow. Losing a match resets the current streak to zero, though your best-ever figure survives. It is a small thing that changes how you play a close match: the twelfth win in a row is worth thinking about, where a single pick-up game is not.

At the end of a match you get a result card drawn on your own device — the ruleset, the difficulty, the number of hands and the final score, headed by "I beat the Hard AI" if that is what happened. You can share it straight out or save the image. It is a brag card rather than a leaderboard: there is no ranking to climb and no account holding your history.

Each hand's result is announced before the next is dealt, points spelled out, so you can always see why a hand was worth what it was worth.

06  Questions people ask

Is there a free dominoes game I can play against the computer online?

Yes — this one. It is free and ad-supported, plays on a standard double-six set, and needs no account, no download and no email address. Open the page and deal.

What is the difference between Block and Draw dominoes?

What you do when you cannot move. In Block rules you pass your turn immediately and the hand carries on. In Draw rules you take tiles from the boneyard until you can play, and only pass once it is empty. Draw games run longer and depend more on what you happen to pull.

How does All Fives scoring work?

After every tile, add the two open ends of the line together. If the total is a multiple of five, the player who laid that tile scores it immediately — a total of fifteen pays fifteen. A double sitting at an end counts both halves, so six-six on the end is twelve. Hand-end awards are rounded to the nearest five, and because points land mid-hand you can reach a hundred while losing the hand in front of you.

Can you play dominoes on a phone?

This one is built portrait-first for one-thumb play: tiles are sized to tap rather than drag, the board fits the screen without pinching, and it works the same way on a desktop.

How do you beat a computer at dominoes?

Against the Hard opponent here, three things matter. Shed heavy tiles early, because a locked hand pays your whole remaining pip total to whoever is lighter. Avoid passing when you have a legal move — every pass tells the AI exactly which numbers are dead in your hand, and that memory lasts the rest of the hand. And in All Fives, look at what your move leaves on the ends, because setting up a total of five or ten is an invitation for it to take those points on its next turn.

What happens if neither player can move?

Two passes in a row ends the hand as blocked. The player with the lighter hand wins it and scores the opponent's full pip total, unless the two hands are level on pips, in which case the hand is a tie and nobody scores.

07  More from the shelf

• Tilewright — Draw seven tiles. Outword the AI.
• Chess — Beat the engine. Post the win.
• Backgammon — Roll the race. Take the cube.
• Fiveaside — Score past the keeper. Post the scoreline.

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