How to do a domino prediction

Secretly take one domino (not a double) out of a full set and note its two numbers as your prediction. A spectator links the rest into one long chain, matching ends as in the game. The two numbers at the ends of the chain are always the two numbers you predicted. It works because a full set can always be laid out as a closed loop, and you removed one link.

What does the audience see?

You place a sealed envelope on the table and push a pile of dominoes towards a spectator. They mix the tiles face up, then build one long chain, joining each tile to the next by matching numbers, exactly as in a game of dominoes. They can start anywhere and join the tiles in any order they like, as long as every tile ends up in a single line. When the last tile goes down, you point to the two open ends of the chain. Say they show a 2 and a 5. The spectator opens the envelope. Inside: “2 and 5.”

What do you need?

• A complete set of dominoes. A standard double-six set has 28 tiles, with every pairing of the numbers 0 (blank) to 6 appearing once.
• An envelope, a card and a pen for the prediction.
• A pocket to hide one domino in.

Check the set is complete before you start. If a tile is already missing, the ends will not match your prediction.

How do you set it up?

1. Remove one tile that is not a double. For example, take the 2–5 and leave the 2–2 and 5–5 in the set.
2. Hide it. Put it in your pocket, under the table or in your wallet. It should never be seen again during the trick.
3. Write the prediction. Write the two numbers on a card (“2 and 5”), seal it in the envelope, and keep the envelope in view from the start.

How do you perform it?

1. Introduce the prediction. Set the sealed envelope down where everyone can see it, and ask someone to keep a hand on it.
2. Hand over the dominoes. Let the spectator mix them face up. Don’t count them out or draw attention to how many there are.
3. Explain the rule. Every tile must join the chain, and touching ends must show the same number. They can choose every connection.
4. Stay hands off. Step back while they build. The fewer times you touch a tile, the more impossible the ending feels.
5. Point to the ends. When the chain is finished, name the two open end numbers aloud.
6. Open the envelope. Have the spectator read the prediction.

Why does it work?

A full set of dominoes can always be joined into one chain that loops back and connects to itself. Every number appears on an even number of tile ends, so every end can be paired with a matching one and nothing is left over.

Taking one tile out breaks that loop at one link. Whatever order the spectator chooses, the chain they build is the loop with that link missing, so its two open ends must be the two numbers on the tile in your pocket. The cs4fn project at Queen Mary University of London explains the same principle and puts it simply: the end of the spectator’s chain “will be missing that link”.

That is also why you never remove a double. A double carries the same number on both ends, so taking it away doesn’t break the loop, and you would have nothing useful to predict.

Where does the trick come from?

Based on our research, the earliest mention we’ve found of naming the end numbers of a domino row is Professor Hoffmann in Modern Magic, 1876. Its chapter on tricks with dominoes and dice includes a trick in which someone arranges the dominoes in a row in your absence, and you then name the numbers at the two ends without seeing them.

How can you make it stronger?

• Use more than one envelope. Seal the prediction in an envelope inside another envelope, or keep it in plain view the whole time, so nobody thinks you wrote it at the end.
• Let them change their mind. Invite the spectator to undo part of the chain and rebuild it differently. The ends still match, which makes the free choice feel real.
• Repeat with care. If you do it twice for the same people, swap the hidden tile first, otherwise the same numbers come up again.
• Tie it to a story. Present it as a test of how people “connect” things, then reveal you knew how their chain would end.

What helps you take it further?

• Modern Magic by Professor Hoffmann, free from our public-domain library. Its contents include a full chapter of tricks with dominoes and dice alongside cards, coins and stage apparatus, each explained step by step with the original engravings.
• Trio by The Other Brothers: a triple prediction for parlour or stage in which three volunteers make choices that you prove you knew all along. It comes with large, full-colour predictions, a cloth bag with a special gimmick, custom envelopes and video instructions.

For more self-working mind-reading, try the dice total prediction, the magic number nine trick or the age cards trick, and browse our easy mentalism collection.

Frequently asked questions