Rows of small matchboxes glued together like a chest of drawers, each with a hand-drawn noughts and crosses grid, beside a pencilled game on paper
AI-generated image, not a photograph of a real person or place.
doodletictac

A CLASSIC IN MACHINE LEARNING

A machine made
of matchboxes.

SHAKE THE BOX the bead picks the move

  • One box per position
  • Beads are the odds
  • Results change the beads
  • Learning by trial and error

In 1961 a pile of matchboxes learned to play noughts and crosses.

Donald Michie had no computer to hand, so he built a learning machine from matchboxes and coloured beads. Each loss took beads away and each win added more, until it stopped losing. This independent guide explains how MENACE worked and what it shows about how machines learn.

Updated

Feed it a result

THE SHORT ANSWER

Reward the wins,
punish the losses.

MENACE had no program.
Its memory was the beads in each box.

THE BOXES

One box per position

Each matchbox showed one board position. Michie's 1963 paper counts 287 essentially distinct positions for the opening player; accounts of the machine give 304 boxes.

How it was built

THE MOVE

Shake, tilt, read the bead

Beads were colour-coded to squares. The operator shook the box and tilted it, and a V-shaped card picked the first bead to arrive: that was the move.

Play a turn

THE LEARNING

Beads change the odds

After a loss the chosen beads were confiscated; after a win, three extra beads were added to each box used. Good moves grew more likely.

Feed it a result

A QUICK RESULT CHECK

What happens
to the beads?

Pick how a game ended to see what the operator did to MENACE's matchboxes. The bar shows how strongly the moves it played are encouraged next time.

Bead check

Choose a result
MENACE lostBeads removed

The selected bead was confiscated from each box used, so those moves became less likely. If a box ran out of beads, MENACE resigned.

A drawOne bead added

In the maiden tournament a draw was reckoned a good result and earned a unit bonus: one extra bead of the chosen colour in each box used.

MENACE wonThree beads added

A win was treated as an exceptionally good result, rewarded with three extra beads in each box used, so winning moves were much more likely to recur.

Source: Michie, Experiments on the mechanization of game-learning, Part I (The Computer Journal, 1963).

Based on Michie's 1963 paper in The Computer Journal and accounts of the machine's maiden tournament.

TWO NUMBERS WORTH KNOWING

Learned in
about twenty games.

The maiden tournament pitted MENACE
against its builder, playing carefully.

220 games

Games in the maiden tournament

The tournament lasted 220 games over 16 hours. Playing the best strategy he knew, Michie found MENACE drew consistently after about 20 games.

THE TOURNAMENT · 1961

304 boxes

Matchboxes in MENACE

Rotations and mirror images were treated as the same position and MENACE always played first, which kept the number of boxes small enough to build by hand.

THE MACHINE

A Ferranti Pegasus 2 computer later simulated the machine, playing both sides at about a game a second. Michie noted that random games favour the opening player by about 2 to 1.

HOW ONE GAME WENT

Find the box,
shake, play.

A hand-drawn noughts and crosses game on squared paper next to small heaps of coloured beads sorted by colour
AI-generated image, not a photograph of a real person or place.

Playing MENACE needed a human operator. These are the steps described by Michie and in later accounts of the machine.

  1. Find the box for the board

    Locate the matchbox showing the current position, or a rotation or mirror image of it.

  2. Shake and tilt it

    The beads run to the front and the V-shaped partition selects the first bead to arrive.

  3. Play the colour's square

    Each colour stands for a square; put MENACE's mark there, set the bead aside and leave the tray ajar.

  4. Settle up at the end

    Remove the chosen beads after a loss, add one for a draw and three for a win.

WHY IT STILL MATTERS

Trial and error,
made visible.

An open matchbox tray holding coloured glass beads, with a V-shaped card at the front where one bead has rolled into the point
AI-generated image, not a photograph of a real person or place.

Michie wrote that the strength of reinforcement should be greatest for the last moves of a game and weaker towards the start. So the first-move box began with four beads of each colour, later boxes with three, two and then one, and each lost bead mattered more late in the game.

The University of Edinburgh traces its artificial intelligence research to a small group Michie set up at 4 Hope Park Square in 1963. MENACE is now a favourite teaching example of reinforcement learning, rebuilt in classrooms and simulated online.

Questions

Questions people ask

What was MENACE?

The Matchbox Educable Noughts And Crosses Engine, a learning machine built by Donald Michie around 1961 from matchboxes and coloured beads. It played noughts and crosses and improved by trial and error.

How did a matchbox choose a move?

Each box showed a board position and held beads whose colours stood for the empty squares. The operator shook and tilted the box, and the bead caught at the front by a V-shaped card gave the move.

How did it learn?

After each game the beads it used were changed: removed after a loss, one added for a draw and three added for a win. Successful moves became more likely, failing ones less likely.

Did MENACE become unbeatable?

Against careful play it learned to draw. In its 220-game maiden tournament it drew consistently after about 20 games, though Michie could sometimes beat it by switching openings until it adapted.

Is this page linked to any brand?

No. It is an independent guide to the history of a learning machine. The name is used only in the sense of tic-tac-toe, the American name for noughts and crosses.

Sources

Where the facts come from

  1. Michie (1963), Experiments on the mechanization of game-learning, Part I, The Computer Journal (PDF copy, MIT CSAIL)
  2. University of Edinburgh School of Informatics: History of Artificial Intelligence at Edinburgh
  3. Chalkdust magazine: Menace, the Machine Educable Noughts And Crosses Engine
  4. mscroggs.co.uk: MENACE, Machine Educable Noughts And Crosses Engine (with a playable simulation)
  5. Wikipedia: Matchbox Educable Noughts and Crosses Engine

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