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A calm warm study with shelves of books, a globe and glass bottles, a teenager planning a clever search strategy on a paper grid

TerminalSweep

Type your moves, then write a bot (out of rules, not code) and find out which strategy actually wins.

💻 Open the terminal →
A fresh rookie board, every square hidden. The terminal makes the first move for you, on the centre square, which is always safe. Tap to see it.

The rules are the cast

  • done. A number that already touches all its mines — its other neighbours are safe.
  • full. A number whose hidden neighbours are exactly the mines it still needs — flag them.
  • subset. One number’s hidden squares sit inside another’s — the difference is decided.
  • guess-safest. No sure move left: open the square with the lowest exact mine odds.
  • guess-random. No sure move left: open anything. (Is it really worse? Race it.)

TerminalSweep is for ages 15–18. Nothing is uploaded; there’s no leaderboard.

A case · you decide

A case: Tomasz’s tournament bot

Tomasz — a 16-year-old entering a solver bot in his coding club’s Minesweeper tournament

The idea in play: ORDER the rules — sure moves first, the least-bad guess last — and measure on the same boards.

Tomasz’s bot clears the easy boards but freezes on about a third of them. The tournament is Friday.

His bot knows three sound rules: open around a satisfied number, flag a number’s last hidden squares, and the subset rule. Whenever none of them fires, it stops — “stuck”.

A friend says: “Just guess randomly when you’re stuck.” Another says: “Guess first — it’s faster.” Tomasz decides to test instead of arguing.

Where does the guess block go?

His bot now wins 72%. How should he report it?

Build your own bot →

Where this game comes from

Mine-clearing number puzzles

Grid games where numbers tell you how many hidden mines are next door appeared on home computers in the early 1980s. The best-known version was made by Curt Johnson, and ported to Windows by Robert Donner; it came out in a Microsoft Entertainment Pack in 1990 and then with Windows 3.1 in 1992. In that classic game some boards force a guess, often a coin toss between two squares.

One thing to hold: Each number is a promise about the eight squares around it, and nothing else.

Why it matters: In 2000 the mathematician Richard Kaye proved that deciding whether a board’s numbers can all be true is among the hardest problems in a famous class called NP (it is “NP-complete”). A quick way to check any board would answer one of the biggest open questions in mathematics.

What we don’t know: Who wrote the very first one is still argued about; several early games had the same idea.

Dates:

  1. 1990 Curt Johnson and Robert Donner’s game ships in a Microsoft Entertainment Pack.
  2. 1992 It comes with Windows 3.1.
  3. 2000 Richard Kaye proves the board-checking problem is NP-complete.

Sources: Richard Kaye, “Minesweeper is NP-complete”, The Mathematical Intelligencer 22 (2000) · Microsoft Windows 3.1 (1992) · Wikipedia, “Microsoft Minesweeper” (read 2026-10-20)

What next? Pick a door

Chosen from what this app is about. What you open is remembered on this device only.