Minesweeper

How to play

Mines are hidden under the covered squares. Opening a square either sets one off, which ends the game, or reveals a number between one and eight telling you how many of the eight squares touching it are mined. A square with no mined neighbours shows nothing at all and takes its blank neighbours with it, which is why one lucky click can peel back a quarter of the board. You win by opening every square that is not a mine; the flags are only bookkeeping and the game does not require you to place a single one.

The opening click cannot lose, and not by luck. The board is genuinely empty when the page loads — no mines exist until you click — and only then are they scattered, with the square you picked and all eight of its neighbours excluded from the draw. That guarantees your first square shows a zero, so the game always begins by opening a region rather than a lonely 3 you can do nothing with.

Three sizes are available. Beginner is 9 by 9 with 10 mines, Intermediate is 16 by 16 with 40, and Expert is 16 rows by 30 columns with 99. Each keeps its own best time, shown in the third counter, and switching size deals a fresh board straight away.

Controls

• Mouse — left click opens a square, right click plants or removes a flag.
• Touch — tap to open, or press and hold for roughly half a second to flag. If holding is awkward, switch on Flag mode and every tap plants a flag instead until you switch it off again.
• Keyboard — the arrow keys walk the focus around the grid one square at a time, Enter or Space opens the focused square, and F flags it. Only one square is in the tab order at a time, so tabbing away from the board never means pressing Tab four hundred times.
• Mines left is the mine total minus the flags you have placed. It is arithmetic, not intelligence: flag ten wrong squares and it will happily read zero.

Subtraction, not luck

The single move that separates players who finish Expert from players who die on it is comparing two numbers instead of reading one. A number on its own only tells you something when it is satisfied — a 1 with exactly one covered neighbour, or a 3 with exactly three. Those are worth taking, and they run out fast.

The real supply of certainty comes from overlap. Take a 2 and a 1 sitting side by side along the edge of an opened region. Look at the covered squares each of them touches. If everything the 1 touches is also touched by the 2, then the mine the 1 is counting is one of the mines the 2 is counting, so the second mine of the 2 has to be in the squares only the 2 can see. Subtract the smaller clue from the larger, apply the difference to the squares that are not shared, and you get a fact rather than a hunch. Two clues, no guessing.

The same subtraction covers the pattern everybody eventually recognises by shape: a 1, a 2 and a 1 in a row along a wall of covered squares. The two ends are mines and the middle is safe, every time, and you do not have to memorise that as a rule because it falls straight out of comparing each pair.

Then there is the counter. Mines left is a constraint that applies to the entire board at once, and it decides more endgames than any local pattern. When it reads 2 and you can see a clue proving both of them sit in one corner, every remaining covered square anywhere else on the grid is safe and you can open them without looking. On Expert this frequently converts the last two minutes of careful crawling into ten seconds of clicking.

None of this makes guessing extinct. A minority of boards genuinely end with two covered squares, one mine between them and nothing in the numbers to tell them apart. When that happens you are not being careless, you are being unlucky, and the correct response is to pick one and move on.

Two conveniences this board leaves out

There is no chord click here — the trick where clicking a satisfied number opens all its unflagged neighbours at once. It is a speed tool that rewards accurate flagging, and leaving it out means flags stay optional rather than becoming compulsory admin. If you are chasing a fast time you will feel its absence; if you are playing to think, you will not notice.

There is also no question-mark state on squares. The middle marker is a habit from the original desktop game and in practice most players either ignore it or turn it off, because a maybe-flag looks too much like a flag when you are scanning quickly. Covered or flagged is the whole vocabulary here.

Where the game came from

Grid games built on counting hidden hazards were circulating on home computers in the early 1980s, but the version everyone actually met arrived with Microsoft Windows: Minesweeper shipped with Windows 3.1 in 1992, credited to Robert Donner and Curt Johnson, and stayed in the operating system for the best part of two decades. It was bundled partly as a mouse tutorial, which is why the two-button interaction of open and flag is so central to it.

Its afterlife is more interesting than its origin. Competitive players still keep timed records on the three classic sizes, and the game turns up in computer science courses because working out whether a given Minesweeper position is consistent is a genuinely hard problem, not a toy one. The implementation on this page is our own, written for this site; the rules and the three board sizes are the shared conventions everybody uses.

Questions players ask