Minesweeper Patterns
The 1-2-1 pattern is three numbers, 1, 2 and 1, in a row along a straight edge of covered squares: the squares next to the two 1s are mines and the square next to the 2 is safe. The 1-2-2-1 works the same way, with mines next to the two 2s and safe squares at both ends.
A pattern is a small group of numbers that always means the same thing. Learn a handful of them by sight and you stop working through each square one at a time. You see the shape, and you know where the mines are.
This page covers the eight that matter most, in the order most players learn them. Each one has a small example. The 1-2-1 and 1-2-2-1 also have worked examples from real games on this site, and there's a section on boards where a pattern looks right but isn't. At the end there are practice puzzles to try them on.
How to read the examples
- Blue squares are still covered.
- Red squares are covered squares that must be mines.
- Green squares are covered squares that must be safe.
- Flags are mines the player had already marked.
- The edges of each example are the edges of the board. Patterns along a wall work the same way along any straight edge of opened squares.
Every example on this page is checked by a program when the site is built. It tries every possible way the mines could sit, so a square is only drawn red or green if the numbers really prove it.
1. Full numbers
Start here, because everything else builds on it. A number tells you how many mines touch it. If it touches exactly that many covered squares, they are all mines. If it already has all its mines, every other square around it is safe.
On most boards this simple check does more than half the work. Go round the edge of every opening and look at each number on its own before reaching for anything cleverer.
2. The 1-1 from an edge
When a 1 sits against the edge of the board, it touches only two covered squares. If the next number along is also a 1, it touches those same two squares plus one more. Its one mine must be the same mine as the first 1's, so the extra square is safe.
It works from any edge, including the end of a row of open squares, and it's one of the quickest ways to get going on a crowded board.
3. The 1-2
A 2 next to a 1 along an edge. The 2 needs two mines among its three squares. The 1 shares two of those squares and can only put one mine there. So the 2's other square, the one the 1 can't reach, is a mine.
The 1-2 turns up everywhere, and it's the building block of the next two patterns.
4. The 1-2-1
Three numbers in a row, 1, 2, 1, along a straight edge. The mines are next to the two 1s, and the square next to the 2 is safe. Read it as two 1-2s back to back: each one puts a mine on its outside square.
Worked example: a 1-2-1 from a real game
This is a Beginner board from this site, at the point where checking each number on its own stops giving anything. The opening in the middle has two rows of numbers along its edges. Look at the lower one: 1, 1, 1, 2, 1, 1. Inside it, on the right, is a 1-2-1 with a straight row of covered squares below.
- Find the 2. It touches three covered squares below it and needs two mines among them.
- The 1 on each side shares two of those squares and can hold only one mine there. So each 1 pushes a mine onto the square on its outside, below the 1 itself.
- That gives the 2 its two mines, so the square directly below the 2 is safe.
- Each 1 now has its mine, so the squares beyond them, at both ends, are safe too.
To play it, right-click the two red squares to flag them (press and hold on a phone), then click the three green ones. In this game they opened as a 2, a 3 and a 1, and the board carried on from there.
5. The 1-2-2-1
Four numbers in a row, 1, 2, 2, 1. Here the mines are next to the two 2s, and the squares at each end are safe. Again it's two 1-2s, this time pointing inwards.
The 1-2-1 and 1-2-2-1 are the two most useful shapes in the game. On Expert they appear on almost every board.
Worked example: a 1-2-2-1 from a real game
Another Beginner board from this site, again at the moment the single-number checks ran out. The top edge of the opening reads 1, 1, 1, 2, 2, 1, 1. The middle four, 1, 2, 2, 1, sit under a straight row of covered squares.
- Take the left 2 with the 1 beside it. The 1 can put only one mine in their shared squares, so the 2's last square, towards the middle, is a mine.
- Do the same from the right: the right 2 and its 1 put a mine on the other middle square.
- Both 2s now have their two mines, so the square above each 1 is safe.
- Each 1's mine is one of the middle pair, so the square beyond each 1, at both ends, is safe as well.
Flag the two red squares and open the four green ones. On this board they opened as 2, 2, 1 and 1.
When a pattern seems to fit but doesn't
The 1-2-1 and 1-2-2-1 are only safe to use when the numbers touch nothing except the straight row of covered squares beside them. Before you use one, check the squares around the ends of the row. These real boards show what to look for.
The covered edge bends
Here the bottom edge of the opening reads 2, 1, 2, 1, and the 1, 2, 1 on the right looks like a textbook pattern. But the last 1 sits on a corner: as well as the covered squares below it, it touches covered squares above it and to its right, where the edge turns upwards.
The simple reading says the square below that last 1 is a mine. It isn't proven: the 1's mine could be around the corner instead. In this game that square was empty, so flagging it would have been a mistake. Part of the pattern still holds: the numbers do prove the mine below the left 1 and the safe squares either side of it.
A flag is already touching a number
This board shows a 1, 2, 1 along the top of the opening, with a straight row of covered squares above. But a flag sits just below it, and that flag touches both the 2 and the right-hand 1.
Take the flag away first, as in section 6 below. The 2 becomes a 1 and the right-hand 1 becomes a 0, so the row is really 1, 1, 0. The 0 means both squares above it are safe, including the one the simple 1-2-1 reading would have flagged. The only mine left is above the left-hand 1. Whenever a flag touches any number in the row, do this subtraction before looking for a pattern.
The pattern runs into the edge of the board
This one looks risky but is fine. Go back to the first worked example. Its upper row of numbers ends 1, 2, 1 right against the right-hand edge of the board.
The pattern still works: a mine above each 1, and the square above the 2 is safe. The only change is that there's no end square on the edge side to open. We checked this across 20,000 Beginner games dealt by this site, and every one of the 353 straight-edge 1-2-1s and 1-2-2-1s that ran into the edge of the board still worked.
6. Take away the flags
Numbers that already touch flagged mines often hide a familiar pattern. Take the flags off each number in your head and look at what's left. A 2 that touches one flag acts like a 1. A 4 that touches two flags acts like a 2.
Good players call this reduction, and it's how the basic patterns keep working deep into a game, long after the first openings are gone.
7. Count the mines at the end
Near the end of a game, the mine counter becomes part of the logic. Sometimes a covered square doesn't touch any number at all, so nothing on the board can tell you about it. The counter can.
The counter shows the number of mines minus the flags you've placed, so it only helps if your flags are right.
8. The 50/50 no pattern can solve
It helps to recognise the spots that can't be solved too, so you don't waste time on them. Two squares against an edge, touched by the same numbers, with one mine between them: nothing on the board can ever tell them apart.
When you find one, clear every other part of the board first, since a new number can sometimes remove the need to guess. If you'd rather never meet one, play No guess mode, where every board can be cleared by logic. There's more on why these happen in why Minesweeper sometimes makes you guess.
Practice puzzles
Each puzzle is a board in the middle of a game. Click every square you can prove is safe. A wrong click doesn't cost anything, so take your time. The edges of each puzzle are the edges of the board.
Puzzles 7 to 11 are whole Beginner boards from real games on this site, each at a point where checking single numbers has run out.
Ready for a real board? Try today's Daily Minesweeper, which can always be solved with logic like this, or start with Intermediate. For tips beyond patterns, such as chording and when to guess, see the strategy page.
Questions people ask
What is a pattern in Minesweeper?
A small group of numbers that always means the same thing. Once you know a pattern by sight, you can mark its mines and safe squares without working through the logic each time.
Which patterns should I learn first?
Full numbers first, then the 1-2-1 and 1-2-2-1. Those three cover a large share of the deductions on Intermediate and Expert boards.
What does 1-2-1 mean in Minesweeper?
Three numbers, 1, 2 and 1, in a row along a straight edge of covered squares. The squares next to each 1 are mines and the square next to the 2 is safe.
Does the 1-2-1 still work against the edge of the board?
Yes. When the row of numbers runs into the edge of the board, the mines are still next to the two 1s and the square next to the 2 is still safe. The only difference is that there is no end square on the edge side to open.
Why did the 1-2-1 not work?
Usually because the covered squares are not in a straight line, or a flag already touches one of the numbers. If a number touches covered squares outside the straight row, or a flag, the simple reading no longer holds. Work through each number on its own instead.
Can patterns solve every board?
No. Some boards on the classic levels reach a point where two squares are equally likely to be the mine, and no pattern helps. In No guess mode every board can be cleared by logic.