Minesweeper rules
Updated July 2026
Minesweeper has three rules and one idea. The rules take a minute. The idea — that every move should be provable — takes the rest of the game.
The board
A rectangular grid of covered tiles. A fixed number of them hide mines; the rest are safe. You are told how many mines exist, never where. Your job is to uncover every safe tile. You do not need to find the mines, only to avoid them.
What the numbers mean
Open a safe tile and it shows a number from 1 to 8: how many of the eight surrounding tiles contain a mine — including diagonals. That is the only information the game ever gives you.
A tile with no adjacent mines shows nothing at all, and the game automatically opens its neighbours for you — which cascades, which is why one lucky click can clear half a board.
Flags
Right-click (or long-press on a phone) to plant a flag on a tile you believe hides a mine. Flags are purely for your own bookkeeping: the game does not verify them, you cannot lose by flagging wrongly, and you do not need them to win. Their real value is that a flagged tile is one your eyes can stop re-deriving.
How you win and lose
You win the moment every non-mine tile is uncovered. Flags are irrelevant to this — leave every mine unflagged and you still win.
You lose the moment you open a mine. In classic minesweeper that ends the game immediately, which is why the forced 50/50 at the end of a clean solve is so infuriating.
First-click safety
Nearly every modern implementation guarantees your first click is not a mine, and most also guarantee it opens a cascade rather than a bare number. Mines are placed after that click. It is a convention, not a law — very old versions could kill you on move one.
Chording
If a number already touches exactly that many flags, clicking it with both buttons (or middle-click) opens all its remaining neighbours at once. This is standard, legal, and the foundation of fast play. It also punishes sloppy flagging: chord against a wrong flag and you open a mine.
Standard sizes
Beginner — 9×9 with 10 mines (12% density).
Intermediate — 16×16 with 40 mines (16%).
Expert — 30×16 with 99 mines (21%).
Density is what makes expert hard, not size: at 21% the board rarely gives you the roomy cascades that make beginner boards feel generous.
What the rules do not promise
Nothing in the rules says the board is solvable. Mines are placed at random, so a classic board can leave you with two tiles, one mine, and no way to tell which. Some modern versions — including Grimlings — run a solver over every board first and throw away any layout that cannot be finished by logic. Why that matters.
Frequently asked
What does a number actually count?
Mines in the eight adjacent tiles, diagonals included. Never the tile itself.
Can I win without flagging anything?
Yes, and expert players usually do.
Is the first click always safe?
In modern versions, yes.
Three rules, real deduction — and never a coin flip.
