Minesweeper

• Make your first click in the middle of the board rather than in a corner. A middle square opens the eight squares around it and a corner square opens three, so the same click buys nearly three times the information.
• Read every number against the flags already touching it. A 1 that touches one flag has had its mine accounted for, so every other square around that 1 is safe and can be clicked without further thought.
• The reverse rule is just as strong. If a number equals the count of its still-covered neighbours, all of those neighbours are mines: a 3 with exactly three covered squares beside it has told you where all three sit.
• Learn the 1-2-1 pattern. Three numbers reading 1, 2, 1 in a line, with three covered squares along their edge, always resolve the same way — the two outer covered squares are mines and the middle one is safe. It falls straight out of the counting and has no exceptions.
• The 1-2-2-1 pattern is its companion. Four numbers reading 1, 2, 2, 1 above four covered squares mean the two middle squares are mines and the two outer ones are safe, the opposite arrangement.
• When two numbers overlap, subtract one from the other. If every covered square that one number can see is also seen by a second number, and both still need the same count of mines, the extra squares only the second can see are all safe. Most positions that look like a guess come apart here.
• Keep the flag counter honest. You get exactly as many flags as there are mines, so if it reaches zero while covered squares remain, one flag is in the wrong place.
• Work the edges early. An edge square has five neighbours and a corner three, so those numbers constrain far fewer squares and resolve much faster than numbers in open ground.

This version needs a pointing device. Clicking or tapping a square uncovers it, and that works with a mouse, a trackpad or a finger. Placing a flag is different: it needs a genuine right-click — the right-hand mouse button, or a two-finger tap on a trackpad. Pressing and holding on a touchscreen does not place a flag here, and we would rather say so than have you keep trying. On a tablet with no mouse you can still finish and win any board, because winning only requires uncovering the safe squares; you hold the mine positions in your head instead of marking them. There is no keyboard control of the grid.

The squares are sized as a share of your window, so a wide window gives large squares and a narrow phone gives small ones — a computer, or a tablet turned to landscape, is the easier way to play. Numbers are colour-coded: 1 blue, 2 green, 3 red, 4 purple, 5 orange, all on white. The 6 and 7 are drawn in pale blue and yellow and are hard to read against white; they are also rare, and on Easy you will almost never meet one. Mines are drawn as a star rather than a bomb. A clock in the corner starts on your first click and counts upward, but it only records how long you took — nothing is timed against you and you may sit and think as long as you like. Your chosen difficulty is remembered on that device.

The version most people remember arrived with Windows. Curt Johnson wrote a game called PM Mine in 1989 to teach himself the OS/2 Presentation Manager interface, and his Microsoft colleague Robert Donner rewrote it for Windows as Win Mine. It reached the public in the first Microsoft Entertainment Pack in 1990, and in 1992 it was folded into the standard installation of Windows 3.1, where it replaced Reversi. That is how a small puzzle written to practise a graphics library ended up on a great many of the world's desks.

The idea is older, and its parentage is genuinely disputed. Mined-Out, published in 1983 for the ZX Spectrum, is often named as the first of the line, and Johnson has acknowledged borrowing his design from an earlier game while denying it was that one. What is not in doubt is why it lasted: a board of numbers that each describe their own eight neighbours is a small, entirely closed logic system, and almost every position can be reasoned out rather than guessed. If that is the part you enjoy, Nonogram and Sudoku work the same muscle.

This is a self-hosted, open-source version of Minesweeper (source), used under its MIT licence and hosted here so it loads fast and shows no third-party adverts inside the game. Browse all of our free games.