Minesweeper Patterns: 1-2-1, 1-2-2-1 and More
Minesweeper patterns are shortcuts for reading neighbouring numbers along a straight line of closed squares. 1-2-1 means mines next to both 1s and a safe square next to the 2; 1-2-2-1 means mines next to both 2s and safe squares next to the 1s. Subtract any flagged mines from a number first, and many awkward borders turn into one of these.
How to use this pattern sheet
Patterns are read along a border: a straight row of numbers with a straight line of closed squares beside it. In every diagram below, the ringed numbers are the ones that prove the result, an orange spiky marker is a square that must be a mine, and a green tick is a square that must be safe. Unless a caption says otherwise, the picture is a short stretch of a longer border, so the board carries on past both ends.
If you're new to reading numbers, flagging and chording, start with How to Win Minesweeper. This page is the reference sheet to keep open next to the board.
| Pattern | What it tells you |
|---|---|
| 1-2 | The square only the 2 touches is a mine; the square only the 1 touches is safe. |
| 1-2-1 | Mines next to both 1s, the square next to the 2 is safe. |
| 1-2-2-1 | Mines next to both 2s, the squares next to the 1s are safe. |
| 1-1 from a wall | Starting at the board's edge, the third square along is safe. |
| Flags first | Subtract flagged mines: a 2-3-2 beside a flag can be a 1-2-1 in disguise. |
| 1-2-2-2-1 | Only the middle square is certain (a mine); the rest needs other numbers. |
1-2: the rule behind every pattern
Take a 1 and a 2 side by side along the border. Each touches three closed squares, and they share two. The 1 allows at most one mine in those shared squares, so the 2 has to find its second mine in the square only it touches. That same 1 has its single mine somewhere in the shared pair, so the square only the 1 touches is safe.
Every other pattern on this page is this comparison done twice, once from each end. When you meet a shape that isn't on any list, do the same thing: pick two neighbouring numbers, find the squares only one of them touches, and ask how many mines each must hold.
1-2-1: mines beside the 1s
Read the 1-2 rule from the left and then from the right. Each 1-2 pair puts a mine on the far side of the 2, so the mines land next to the two 1s. The 2 now has both of its mines, which makes the square straight next to it safe, and each 1 is satisfied, so the outer squares are safe too.
1-2-2-1: mines beside the 2s
Add one more 2 and the answer flips. The left 1-2 pair puts a mine next to the second 2; the right pair puts one next to the first 2. So both mines sit next to the 2s, and the 1s, already satisfied, make the squares beside them safe.
An easy way to remember both: in 1-2-1 the mines are under the 1s, in 1-2-2-1 they're under the 2s.
1-1 from a wall
A number against the edge of the board touches fewer squares, which makes it powerful. A 1 in the end position touches only two closed squares. The 1 next to it touches those same two plus one more. Its mine is already in the first two, so the third square along is safe. Open it, and the new number usually settles the whole corner.
The same thing happens next to any opened square, not just the board's edge: what matters is that the first number touches only two closed squares.
Flags first: patterns in disguise
Real boards are messier than pattern sheets. Numbers along a border often also touch a mine you've already found on the other side. Before you look for a pattern, subtract the flags: a 3 that touches one flag is really a 2 for the squares that are left. This is often called reduction, and it turns up hidden patterns all the time.
Check which numbers the flag actually touches. In the second picture the final 1 sits too far away, so it keeps its value; only the first three numbers drop by one.
1-2-2-2-1: the pattern that only half solves
Not every shape gives a full answer. A 1-2-2-2-1 along a straight border has exactly two ways to place its mines, and they agree on only three squares: the one beside the middle 2 is always a mine, and the squares beyond each end of the pattern are always safe. The other four squares pair up: either the second and fifth are mines, or the third and sixth are.
So take what's certain (flag the middle mine, open the two safe squares) and let the new numbers decide the rest. The lesson goes beyond this one shape: a pattern is only a pattern if it forces an answer. When a shape looks familiar but you can draw two different mine layouts that both fit, keep looking elsewhere.
Practise the patterns
On GameLake every board is generated so it can be solved by logic from your first tap, which makes it a good place to drill these shapes: when you're stuck, a deduction is always there. Tap Teach me and Hop rings the numbers to read and the squares they decide, then explains why in plain words, the same way the diagrams on this page do.
- Play Easy (9×9, 10 mines) until you spot 1-2-1 and 1-2-2-1 without counting.
- Move to Medium (14×10, 21 mines) and make subtracting flags a habit before every pattern check.
- On Hard (18×12, 36 mines), look for 1-2 pairs first: they're the most common and they unlock the rest.
For the full rules and where the game came from, see Minesweeper rules and history.
Frequently asked questions
What does 1-2-1 mean in Minesweeper?
Along a straight line of closed squares, the mines are next to both 1s and the square next to the 2 is safe.
What does 1-2-2-1 mean in Minesweeper?
Along a straight line of closed squares, the two mines are next to the 2s, and the squares next to the 1s are safe.
What is reduction in Minesweeper?
Subtracting mines you already know about from each number. A 3 touching one flag acts as a 2 for its other squares, which often reveals a familiar pattern.
Do Minesweeper patterns work vertically?
Yes. Patterns work in any direction along a straight border: rows, columns, and next to the edge of the board.
Does every pattern solve completely?
No. A 1-2-2-2-1, for example, only proves the middle mine and the squares beyond its ends. The other squares need information from other numbers.