Minesweeper patterns

Most of a Minesweeper board is solved by a handful of shapes that come up again and again. Learn to spot them and you'll stop reasoning cell by cell and start clearing whole rows at a glance.

Each pattern below is shown twice: as you'd meet it on the board, and with the cells it proves marked, flags for mines and ticks for safe cells. The diagrams are small pieces of board whose edges are the edges of the board. Every marked cell has been checked by computer against every possible arrangement of mines.

A number with just enough covered cells

The first rule of Minesweeper: if a number touches exactly as many covered cells as it has mines, every one of those cells is a mine. The 2 at the top touches just two covered cells, so both are mines. The commonest case is a 1 with a single covered neighbour, often in a corner or along an edge.

A number whose mines are all found

The second rule is the mirror image: once a number touches as many known mines as it shows, its other covered neighbours are safe. The second 1 already touches the flag, so the two cells beside the flag are safe. Opening them shows nothing new here, but the third 1 now has just one covered cell left, the one on the right, and by the first rule that's a mine. Clicking a number like this opens its safe neighbours in one go.

The 1-1 at a wall

Two 1s side by side against the edge of the board. The 1 at the edge touches two covered cells, and one of them is a mine. The next 1 touches those same two cells plus a third. Its one mine is already accounted for by the first pair, so the third cell is safe. The same works against any wall of open cells, not only the edge of the board.

The 1-2

Look at the 1 and the 2 beside it on the bottom row. They share two covered cells, and the 1 says those two hold at most one mine. The 2 needs two, so its third cell, on the far side, must be a mine. That uses up the 1's mine within the shared pair, so the 1's own third cell, on the near side, is safe. Wherever a 1 sits next to a 2 along a line of covered cells, the cell beyond the 2 is a mine.

The 1-2-1

A 1-2-1 along a straight line of covered cells is the best-known pattern of all: the mines are opposite the two 1s, and the cell opposite the 2 is safe. It's the 1-2 seen from both ends: each 1-2 puts a mine beyond the 2, which gives the 2 both of its mines and clears the middle.

The 1-2-2-1

Its close cousin: in a 1-2-2-1, the mines are opposite the two 2s and the cells opposite the 1s are safe. Again it is two 1-2s, one from each end, each putting a mine beyond its 2.

Seeing patterns in the wild

On a real board the patterns rarely sit on a clean edge. Before using one, mentally take away the mines you already know: a 3 touching one flag behaves like a 2, and a 2 touching one flag like a 1. A row reading 2-3-2 with a flag along its other side is often a 1-2-1 in disguise. This "reduce the numbers first" habit is what turns pattern knowledge into speed. The strategy guide covers it in more detail.

Put them to work: play an Intermediate game.