Minesweeper strategy

Minesweeper Patterns and Logic

A pattern is a repeated relationship between clues and their covered neighbours. Learning the relationship matters more than memorising a picture: the same deduction may be rotated, reflected, wrapped around a corner, or hidden behind known flags.

Diagram key Safe to reveal Mine to flagCovered and not yet resolved

Pattern catalogue

The common catalogue falls into six logical families. The first three are covered below; reductions, high-complexity positions, and endgames continue in the advanced guide.

Direct clue rules

Start with the two deductions behind every named pattern: a clue can force covered cells to be mines, or confirm that its other neighbours are safe.

The 2 has exactly two covered neighbours, so both can be flagged.

Foundation

Complete-neighbour rule

When a clue still needs as many mines as it has covered neighbours, every one of those neighbours is a mine.

  1. Subtract any adjacent flags from the clue.
  2. Compare the remaining mine count with the number of unflagged covered cells.
The 1 already touches a flag. The two marked cells cannot contain another mine.

Foundation

Satisfied clue rule

Once a clue already touches its full number of confirmed mines, every other covered neighbour is safe.

  1. Count flags touching the clue.
  2. If that count equals the clue, reveal the other covered neighbours.

Edge and subset patterns

These patterns compare overlapping groups of covered cells. The smaller group fixes part of the larger clue, exposing what the extra cells must contain.

The rightmost covered cell is outside the first 1 group and is safe.

Core

1-1 safe extension

At an edge, the first 1 places one mine inside a small pair. If the next 1 sees that same pair plus one extra cell, the extra cell is safe.

  1. Treat the first clue's covered neighbours as a one-mine group.
  2. The second 1 is already satisfied somewhere in that group, leaving its additional neighbour empty.
The extra neighbour belonging only to the 2 must be a mine.

Core

1-2 forced extension

If a 1 and a neighbouring 2 share the 1 group, the 2 must obtain its second mine from the extra covered cell.

  1. The cells shared with the 1 contain exactly one mine.
  2. The 2 needs one additional mine, so its unshared neighbour is forced.
Flag the two outside cells and reveal the centre cell.

Core

1-2-1

Along a straight frontier, 1-2-1 forces mines on the two outside covered cells and leaves the middle covered cell safe.

  1. Apply the 1-2 extension from the left to force the right outside mine.
  2. Mirror the same deduction from the right to force the left outside mine.
The middle pair are mines. The cells above the outer 1s are safe.

Core

1-2-2-1

A straight 1-2-2-1 frontier places mines in the two middle covered cells; the two outside covered cells are safe.

  1. The left 1-2 comparison forces the second covered cell to be a mine.
  2. The mirrored 2-1 comparison forces the third, satisfying both outer 1s.

Holes, offsets, and triangles

Board edges are not always straight. The common catalogue separates three hole layouts and five triangle layouts, but each is a rotated or widened subset comparison: the smaller candidate set still controls the larger one.

The lower 1 confines one mine to the shared pair, so the upper 1 cannot use the marked extra cell.

Intermediate

Offset 1-1 (hole family)

Two separated 1s can still share the same candidate pair. If one clue sees only that pair while the other sees an extra cell, the extra cell is safe.

  1. Trace the covered neighbours of each 1 instead of relying on a straight number row.
  2. Mark the cells belonging only to the larger neighbour set as safe.
The stepped outline changes the shape, not the 1-2 subset deduction.

Intermediate

Offset 1-2 (triangle family)

When an offset 2 contains every candidate of a nearby 1 plus one additional covered cell, that additional cell is a mine.

  1. Identify the one-mine subset controlled by the 1.
  2. The 2 must take its second mine from the pointed end of the larger set.

Continue with advanced logic

Learn reductions, corner saturation, opposing subsets, dependency chains, mine counting, and contradiction checks.

Advanced patterns