Minesweeper strategy

Most of Minesweeper comes down to a few rules and patterns. In the pictures below, grey squares are covered, red squares must be mines and green squares are safe.

The two basic rules

1. If a number has exactly as many covered squares around it as its value, all of those squares are mines.
2. If a number already has as many flags around it as its value, all its other covered neighbours are safe.

Rule 2 is what chording does for you in one click.

1-1 against a wall

Two 1s next to each other along an edge. The first 1 can only see two covered squares, and the second 1 shares both of them. The one mine of the second 1 is therefore among those two, so its third covered square is safe.

The 1-2 pattern

A 2 touches three covered squares, and the 1 next to it shares two of them and touches no other covered squares. At most one mine sits in the shared squares, so the 2’s third square must be a mine.

1-2-1

Three numbers 1, 2, 1 in a row along a straight line of covered squares. The mines are under the two 1s, and the square under the 2 is safe.

1-2-2-1

Four numbers 1, 2, 2, 1 in a row along a straight line of covered squares. The mines are under the two 2s, and the squares under the 1s are safe.

Both patterns are really the 1-2 pattern used from each end. Once you see that, you can work out longer rows yourself.

Chording saves time

When a number is “satisfied” (it has as many flags as its value), click the number to open all its other neighbours. Flag only the mines you need for chording. You do not have to flag every mine to win.

When you have to guess

Random boards sometimes reach a point where logic cannot tell which square is safe. Before you guess, check the whole board for a safe move you missed, and count the mines left. If you must guess, pick a square that will give you new information if it is safe. The daily board is chosen so it never needs a guess.

Play a game and try the patterns.