Minesweeper rules

A field of closed squares, some of them hiding mines. Open every square that is safe and you have won. Open one that is not and the game is over.

You are not guessing blind. Every square you open that has no mine under it shows a number: how many mines touch it. Working out where the mines must be from those numbers is the whole game.

The board

There are three fields, the same three the game has always had:

• Easy: 9 × 9 squares, 10 mines
• Medium: 16 × 16 squares, 40 mines
• Hard: 30 × 16 squares, 99 mines

On a phone held upright the hard field is drawn standing up, sixteen across and thirty down, so that every square stays big enough for a finger. It is the same field either way.

Opening a square

Click a square to open it.

• A number from 1 to 8 is how many mines are in the eight squares around it — above, below, to the sides and on the diagonals.
• A blank square touches no mine at all. Since nothing around it can be dangerous, the squares around it open by themselves, and so on outwards until the open ground is edged with numbers. One click can clear a large part of the field.
• A mine ends the game.

The first square you open is always safe. The mines are laid only after your first click, and never on that square or next to it, so every game starts with a patch of open ground to work from.

Flags

When you are sure a square hides a mine, plant a flag on it: right-click it or click the mouse wheel on it, or on a touch screen hold your finger on it. There is also a switch beside the board that makes a plain tap plant flags instead of opening squares.

A flag does two things. It stops you opening that square by accident — a flagged square cannot be opened until you take the flag off again. And it counts: the mines left figure is the number of mines minus the flags you have planted.

Flags are for you. The game never checks them while you play, and a wrong flag does not cost you anything until you rely on it.

Flag a square a second time and the flag turns into a question mark: a note that you are not sure yet. It is not a flag — it does not count against the mines left, and it does not stop a click. A third time rubs it out.

Opening around a number

Click a number that is already open, or press the mouse wheel on it, and if you have flagged as many squares around it as the number says, every other square around it opens at once. Hold a number down and the closed squares around it that are not flagged light up: that is where its mines can still be.

Both are helps from the old game, and together they are Simple mode. It is off unless it is turned on: on your own before a game, and at a friend's table by whoever opened it, for everyone at once.

This is the quickest way through a field, and the most dangerous one. If one of those flags is wrong, the mine it should have marked is among the squares you just opened.

Winning and losing

You win when every square without a mine is open. You do not have to flag the mines — only to open everything else.

You lose the moment you open a mine. The field is then shown in full: every mine you had not found, and any flag that was on a safe square, crossed out.

Racing friends

Send the link to a table to up to three friends and you race each other across the same field, two, three or four of you.

• You each play on your own copy of it, at the same time. There are no turns.
• Whoever opened the table picks the field, and whether Simple mode is on. Before the start, every friend who has sat down presses Ready, and whoever opened the table sees it and presses Start (at least one friend has to be seated). The race is dealt for everyone seated at that moment; anyone who arrives later watches. The field then opens for all of you at the same moment, from the same patch of open ground, so nobody gets a luckier first click.
• Clear your field first and you win. The race ends there for everyone, and everyone else loses.
• Open a mine and you are out on the spot, and have lost, however far ahead you were. The others race on, and whoever is left alone in the race wins. You see where your mine went off, but no other mine until the race ends.
• You see your own field and how far each of the others has got, as a share of their field cleared. You never see which squares they have opened.
• Resign puts you out too, and you have lost. Someone who loses their connection has 60 seconds to come back; after that the others can race on without them, as if they had resigned.
• Anyone still racing can offer a draw. It is a draw only when everyone still racing agrees; declining it, or carrying on opening squares before agreeing, turns it down.

That makes the race a different game from playing alone. Speed wins it, but a single careless click throws it away, and the player who is behind can still win by being the one who does not blow up.

After a race, Play again deals a new field for the same players straight away, everyone moving one seat round, and keeps the score. Whoever opened the table can press Change settings instead, to pick another field first, and someone new can sit down then — the score is kept then too.

Reading the numbers

A few patterns come up in every game, and knowing them on sight is most of the difference between a slow game and a fast one.

• A 1 with one closed square next to it: that square is a mine.
• A number already satisfied: if a 2 has two flags beside it, every other square around it is safe.
• 1-1 from the edge of the board: when a straight row of numbers starts at the edge of the board with two 1s, those 1s share one mine, so the square beyond the second 1 is safe.
• 1-2-1 along a wall: the mines are under the two 1s, and the square under the 2 is safe.
• 1-2-2-1 along a wall: the mines are under the two 2s.

When nothing on the board decides a square, you have to guess. Guess where it costs least: a square far from the numbers, or one that will open the most ground if it is safe.