Minesweeper patterns: the shapes to know by sight

How to read the pictures

Each picture shows only the squares that matter. Raised teal squares are unopened. A green ring means the square is proved safe, a red ring means it is proved to be a mine, and a yellow flag is a mine you have already flagged. Flat squares with a faint dot are open squares whose own numbers don't matter for this pattern. The edges of a picture are the edges of the board unless a dot square closes them off.

If you are new to the game, start with how to play Minesweeper, which explains the numbers, flags and chording. This page is the reference you come back to: every shape, why it works, and how to spot it quickly.

Why patterns work

Almost every pattern is one idea used again and again. Take two numbers that touch some of the same squares. If one number's mines must all sit in the squares they share, the other number's remaining squares can be settled: safe if it has no mines left to place, mines if it needs exactly as many as it has squares left. Patterns are simply the shapes where that idea pays off so often that it is quicker to recognise them than to reason them out.

That matters because it means you never have to memorise a pattern you don't understand. If a shape looks almost like one below but not quite, fall back on the idea: which squares do these two numbers share, and how many mines can each of them still take?

1-1: the third square is safe

Two 1s side by side, where the first one sits against the edge of the board (or against open squares). The first 1 has only two unopened squares, so its mine is one of those two. The second 1 touches both of them too, so its single mine is already accounted for, and its third square is safe.

The 1-1 is the pattern you will use most. It shows up along every straight edge of an opening. Read it from the end that is blocked: the edge of the board, a flag that already satisfies the number, or a column of open squares.

1-2: the far square is a mine

A 1 next to a 2 along a straight edge. The 2 needs two mines among its three squares. At most one of them can be in the two squares it shares with the 1, so the square only the 2 touches is a mine. Turn it round and you also learn that the 1's mine is in the shared pair, so the square only the 1 touches is safe.

The 1-2 is the 1-1 with a twist: instead of finding a safe square on the far side, you find a mine. Many players learn it as "a 1-2 points at a mine".

1-2-1: mines under the 1s

A 2 with a 1 on each side along a straight row of unopened squares. From the left, the 1 and the 2 form a 1-2, so the square above the right-hand 1 is a mine. From the right, the same thing shows the square above the left-hand 1 is a mine. That is both of the 2's mines, so the square above the 2 is safe, and so are the squares beyond each 1, because each 1 now has its mine.

1-2-2-1: mines under the 2s

Two 2s between two 1s. Each 1-2 at the ends points at the square above the next 2 along, so the mines are above both 2s. Everything else in that row is safe. People often mix this up with 1-2-1; the quick way to remember it is that the mines always sit above the numbers one step in from each end.

Reduction: subtract the flags

Most patterns in a real game don't look like the clean versions above, because some numbers already have a mine flagged beside them. The trick is to subtract the mines you already know. A 3 with one flag next to it behaves exactly like a 2; a 2 with one flag behaves like a 1. Do that for every number in a row and the familiar patterns appear.

Chains round corners

Corners of an opening look awkward because the numbers there touch squares on two sides. The way through is to find one pattern on a straight side first and let it set off the next.

Here the top row is a 1-2, so the top-right square is a mine and the corner 1's mine is in the two squares it shares with the 2. That 1 has nothing left for the squares down its left side, so they are all safe. The 1 below it touches two of those safe squares and one more, so that last square must be its mine. Two squares in the top row are still undecided; the next number you open will settle them.

That is how most of a real board goes: not one big deduction but a chain of small ones, each unlocking the next. If you are stuck at a corner, look along each straight side for a 1-1 or a 1-2 before anything else.

The shapes no pattern solves

Some shapes cannot be settled by any reasoning about the numbers. The commonest is two unopened squares at the edge of the board, both touched by the same numbers and nothing else, with one mine between them. Another is a two-by-two block of unopened squares in a corner with two mines on a diagonal. On a fully random board you will meet these, and the only ways forward are the mine counter (if it says how many mines are left, that can settle it near the end) or a guess.

Recognising these early saves time: if a 50-50 is truly forced, take it as soon as you see it rather than clearing the rest of the board first. Or play no-guess Minesweeper, where every board has been checked so that shapes like this never decide the game.

Cheat sheet

How to spot patterns faster

• Scan edges, not middles. Patterns live on the boundary between open and unopened squares. Follow it like a coastline.
• Look for 1s first. A 1 with only two unopened squares is the start of most 1-1s and 1-2s.
• Reduce as you go. Each time you flag a mine, glance at the numbers round it and subtract.
• Finish a region before moving on. A pattern often opens squares that create the next pattern right beside it.
• Use a hint to learn, not to skip. In Yuzool's Minesweeper a hint rings the numbers it used and says in a sentence why the square follows, so you see the pattern being applied on your own board.