Minesweeper: The Two Patterns That Solve Most Boards

The only two rules you need

The first: if a number has exactly that many unopened neighbours, every one of them is a mine. A 3 touching exactly three closed cells means all three are mines. Flag them and move on — there is nothing to work out.

The second: if a number already has that many flags around it, every other neighbour is safe. A 2 with two flags beside it means the rest of its neighbours can be opened without thinking about it.

Between them these two rules solve the large majority of any board. Most people already know both and still lose, because they apply them to the cell they are looking at rather than sweeping every number after each change.

The 1-2-1 pattern

Along a wall or an edge you will constantly meet three numbers in a row reading 1-2-1. It is worth learning as a shape rather than deriving each time: the mines are under the two 1s, and the cell under the 2 is safe.

Its sibling is 1-2-2-1, where the mines sit under the two 2s. Recognising these on sight is most of the difference between a two-minute board and a five-minute one, because they turn a piece of reasoning into a lookup.

When two numbers disagree

The genuinely useful technique is comparing overlapping neighbourhoods. If a 1 and a 2 share some closed cells, and the 1 has only one cell the 2 does not touch, then that cell is where the 1's mine must be — and the 2's remaining mine has to be somewhere else.

This sounds fiddly written down and becomes automatic quickly. It is the step that clears the places where the two basic rules stall, and it is the reason experienced players almost never end up guessing in the middle of a board.

Opening well

Your first click should be somewhere in the middle, not a corner. A middle cell has eight neighbours, so if it opens empty it cascades across a large area and hands you a lot of edge to work with. A corner has three neighbours and gives you almost nothing.

After that, work the edges of the opened region rather than poking at closed space. Every piece of information on the board lives on that boundary — a number is only useful when it touches something unopened. Clicking into the middle of a closed area is a guess even when it does not feel like one.

The guesses that are genuinely unavoidable

Some boards end in a real fifty-fifty: two cells, one mine, and no information anywhere on the board that distinguishes them. This is not a failure of your reasoning and there is no technique that resolves it. It is a property of the game.

It is rarer than it feels, though. Most positions that look like a coin flip are resolvable by counting the mines left against the closed cells remaining — the global count is information, and it is the one people forget to use. If eight mines are accounted for and two remain, and there are exactly two closed cells in one corner, you are done.