Minesweeper · Rules guide
Minesweeper rules: how to play
What the numbers mean, why flags are optional, what chording is, the three standard board sizes, and why your first click is always safe.
The short answer
- Open every square that is not a mine; opening a mine ends the game.
- Each number counts the mines among the eight squares touching it.
- Flags are bookkeeping — you can win without placing any.
- Chording opens all remaining neighbours of a number whose flags are complete.
- Standard sizes are 9×9 with 10 mines, 16×16 with 40, and 30×16 with 99.
The rules of Minesweeper
A grid hides a fixed number of mines. Open every square that is not a mine and you win; open one that is and you lose. Every number you uncover tells you exactly how many of its eight neighbours are mines — and that is the only information you ever get.
- Left-click (or tap) opens a square.
- A number counts the mines among its eight surrounding squares.
- An empty square has no neighbouring mines, so its neighbours open automatically — which is why whole regions clear at once.
- Flags mark squares you believe are mines. They are bookkeeping, not a requirement: you can win without placing a single one.
Board sizes and the first click
Three standard difficulties have been fixed since the early Windows versions, and every implementation still uses them:
| Level | Grid | Mines | Density |
|---|---|---|---|
| Beginner | 9×9 | 10 | 12.3% |
| Intermediate | 16×16 | 40 | 15.6% |
| Expert | 30×16 | 99 | 20.6% |
| Custom | Any | Any | Above ~25% becomes mostly luck |
The first click is safe
In every modern implementation your first click cannot be a mine, and in most — including this one — it opens a region rather than a lone number, so the game always starts with something to work with. This was not true of the earliest versions, where a first-click loss was possible.
Chording
If a number already has that many flags around it, clicking the number opens all its remaining neighbours at once. This is chording, and it is the main reason expert players are fast. Get a flag wrong and chording detonates the field.
Reading a field
Three habits turn the numbers into a system rather than a guessing game.
1. Work the edges
Only squares adjacent to a number carry information. The frontier between opened and closed squares is where every deduction happens — the interior of a closed region tells you nothing until the frontier moves.
2. Subtract what you know
A 3 with one flag already beside it is effectively a 2 for the remaining squares. Always read numbers as "how many mines are left among the squares I have not resolved".
3. Use overlaps
Two adjacent numbers usually share several squares. If a 1 and a 2 share two closed squares and the 2 has one extra square of its own, that extra square must be a mine. This is the entire basis of pattern solving, and it is covered in the strategy guide.
Common questions
Do you have to flag all the mines to win?
No. The game ends when every non-mine square is open. Flags are a bookkeeping tool — many fast players barely use them.
What does chording mean in Minesweeper?
Clicking a number that already has the right count of flags around it, which opens all its remaining neighbours at once. It is the main speed technique — and it detonates the field if a flag is wrong.
Is the first click always safe?
In modern versions, yes, and usually it opens a whole region rather than a single number. The earliest versions did not guarantee it.
How many mines are there on expert?
99 on a 30×16 grid, a density of about 20.6%. Intermediate is 40 mines on 16×16, beginner 10 on 9×9.
Do you ever have to guess in Minesweeper?
In the classic game, yes — some positions are genuinely 50/50. Modern no-guessing modes generate fields where logic is always sufficient.
What do the numbers mean?
Exactly how many of the eight squares touching that number are mines. Nothing else — not the distance, not the direction.
Play Minesweeper free, right now
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