Minesweeper

How to play Minesweeper

The field is a grid of closed squares. Some of them hide mines. Your goal is to open every square that does not have a mine. You never have to find the mines by opening them; you find them by reasoning, and flags are just notes to yourself.

• Open any square to begin. Your first click is always safe: the mines are laid only after it, and never on that square or the eight around it, so it always opens a small area.
• A number on an open square says how many of its eight neighbours hold a mine. A blank square has no mines around it, so its neighbours open by themselves and the area spreads.
• When you are sure a square is a mine, flag it. The mine counter at the top left shows the total mines minus the flags you have placed.
• When a number already has that many flags next to it, click the number to open all its other neighbours at once. This is called chording, and it saves a lot of clicks.
• Open every safe square to win. Open a mine and the round is over.

Controls on computer and phone

With a mouse, left click opens a square and right click places or removes a flag. Click an open number, or use the middle button, or press both buttons together on a number, to chord. Hold a button down and you can see which squares will be pressed before you let go.

On a phone or tablet, tap to open and press and hold for about a third of a second to flag. If you prefer, switch the Dig and Flag toggle under the board: in Flag mode a tap flags and a long press opens. Tapping an open number chords in either mode.

The keyboard works too. Arrow keys move a cursor around the board, Space or Enter opens, F flags, D or C chords, R starts a new game, and P or Escape pauses. Pausing stops the clock and hides the board, and the game also pauses itself if you switch tabs.

Board sizes, the daily puzzle and options

There are the three classic sizes. Beginner is 9 by 9 with 10 mines, Intermediate is 16 by 16 with 40 mines, and Expert is 30 by 16 with 99 mines. On a tall, narrow screen such as a phone held upright, Expert is drawn turned on its side, 16 columns wide and 30 rows tall, so the squares stay big enough to tap. The neighbours of every square are the same either way, so the puzzle does not change. If the squares would still be too small, they stay at a tappable size and you can drag the board around inside its frame.

The Daily puzzle is an Intermediate board picked by the date, so everyone who plays today gets the same field. It starts with an area already open in the same place for everybody, it never needs a guess, and the clock waits for your first move.

No guessing is an option for the regular boards. With it on, the game keeps drawing boards until it finds one that can be solved from your first click using logic alone. Question marks is another option: with it on, right clicking or long pressing cycles a square through flag, question mark and clear, which is handy for marking squares you are unsure about.

Timer, best times and streaks

The clock starts on your first click and counts in tenths of a second. When you clear a board, your time is compared with your best for that size, and every remaining mine is flagged for you. Each size also keeps your win rate, your current winning streak and your best streak. If you start a new game in the middle of one you have already opened, that round counts as a loss, so streaks have to be earned. Daily boards are tracked separately, with your best time for each day. Everything is saved in this browser.

Minesweeper strategy that actually helps

Most of Minesweeper is a small set of patterns. Once you spot them, boards that looked like guesses turn into plain deductions.

• Start with the easy count. If a 1 touches only one closed square, that square is a mine. If a number already has all its mines flagged, every other closed neighbour is safe.
• Use the 1-1 pattern. When a line of clues starts at a wall with 1, 1, the square that only the second 1 can see is safe, because the first 1 already pins its mine into the squares both of them share.
• Learn the 1-2-1 and 1-2-2-1. On a straight edge, a 1-2-1 means mines under both 1s and none under the 2. A 1-2-2-1 means mines under the two 2s.
• Compare neighbours. If one number's closed squares are all inside another number's closed squares, the difference between the two numbers tells you how many mines sit in the extra squares. This one idea solves most hard spots.
• Chord whenever you can. Flag the mines you are sure of, then click the number to open the rest. It is faster and it reduces misclicks.
• Count at the end. When only a few squares are left, compare the mine counter with them. Sometimes the total number of mines settles a spot that the clues alone cannot.
• If you truly must guess, guess early and pick a square with the best odds, often one far away from known numbers. On a no-guessing board, a forced guess means you missed a deduction, so look again.

A short history of the classic

Games about clearing a minefield from number clues were around on home computers in the early 1980s, including Mined-Out for the ZX Spectrum in 1983 and Relentless Logic in 1985. The version most people know was written by Robert Donner and Curt Johnson and reached millions of office computers when it shipped with Windows in the early 1990s. Its three board sizes, 9 by 9, 16 by 16 and 30 by 16, are the same ones used here. The puzzle has a serious side too: in 2000 the mathematician Richard Kaye showed that deciding whether a Minesweeper position is consistent is NP-complete, which puts the humble game in the same family as some of the hardest problems in computer science.