🎮 How to Play
- Left-click to reveal a cell. The number shows how many mines are adjacent.
- Right-click to flag a suspected mine.
- Reveal all non-mine cells to win. First click is always safe.
About this game
Minesweeper is a single-player logic puzzle in which you clear a grid of hidden cells while avoiding buried mines, using the numbers on revealed cells to deduce exactly where the mines sit. Every number tells you how many mines touch that cell, and reading the numbers against one another is the whole game.
The game traces back to 1980s mainframe puzzles, but the version everyone knows was written by Curt Johnson and Robert Donner and bundled with Microsoft Windows 3.1 in 1990. For a generation it was the first puzzle game people ever opened on a PC. Beneath the simple grid lies real computer science: in 2000, mathematician Richard Kaye proved that deciding whether a given Minesweeper board is consistent is NP-complete, putting it in the same complexity class as some of the hardest unsolved problems in computing.
How the deduction works
Each revealed number is a constraint. When the number of unrevealed neighbours equals the number, all of them are mines; when the satisfied mine count is already met by flags, the remaining neighbours are all safe. Comparing overlapping constraints solves the rest.
For a revealed cell showing N: unrevealed_neighbours = U, flagged_neighbours = F if (U - already_revealed) == N - F: all unflagged neighbours are MINES if F == N: all other neighbours are SAFE Mine density = mines / (rows x cols) // Beginner 0.12, Expert 0.21
- Number = count of mines among the up-to-eight adjacent cells.
- Blank cell = zero adjacent mines; the board flood-fills a whole connected blank region at once.
- Flag = your marker for a cell you have deduced is a mine; it does not affect the board, only your bookkeeping.
- First click = always safe, because mines are placed after you open the first cell.
Worked example: solving a 1-2-1 edge
You have revealed a straight wall of three numbers reading 1, 2, 1, with three unrevealed cells directly beneath them. Here is the deduction.
- The left 1 touches the left and middle unrevealed cells, so exactly one of those two is a mine.
- The right 1 touches the middle and right unrevealed cells, so exactly one of those two is a mine.
- The central 2 touches all three unrevealed cells and needs two mines.
- Combine: the only arrangement satisfying all three is mines under the left and right cells.
- Conclusion: the middle cell is guaranteed safe, so you click it with zero risk.
Standard difficulty levels
The three Microsoft presets differ in grid size and mine density. Higher density forces more guesses and shorter games, which is why speed records are set on Expert.
| Level | Grid | Mines | Density |
|---|---|---|---|
| Beginner | 9 x 9 | 10 | ~12 percent |
| Intermediate | 16 x 16 | 40 | ~16 percent |
| Expert | 30 x 16 | 99 | ~21 percent |
| This game (Easy) | 9 x 9 | 10 | ~12 percent |
| This game (Hard) | 20 x 20 | 80 | ~20 percent |
Common pitfalls
- Guessing before exhausting logic. Most early losses happen because a player clicks at random while a forced-safe cell exists elsewhere on the board. Scan every number first.
- Forgetting diagonals. A cell's count includes all eight neighbours, not just the four orthogonal ones. Miscounting diagonals is the most common deduction error.
- Over-flagging. Flags are a memory aid, not progress. Planting flags you are unsure about pollutes later deductions; only flag cells you have actually proven.
- Ignoring the mine counter. Late in a game the remaining-mines number is itself a constraint. If two cells are left and the counter says one mine, global counting can break a local tie.
- Opening corners and edges first. Corner cells have only three neighbours, so they yield the least information. Expert openers click the centre to maximise the flood-fill.
- Panicking on a forced guess. When no logic remains, pick the cell with the lowest mine probability rather than freezing or quitting. Sometimes a calculated guess is simply correct play.
Related tools
Frequently asked questions
Is the first click in Minesweeper always safe?
Yes, in the standard Windows rules and in this version. The mine layout is generated after your first click so that the clicked cell, and usually its neighbours, are guaranteed mine-free. This is why expert players open with a click in the middle: it tends to flood-fill a large empty region and give the most starting information. Without this rule a player could lose on move one through no fault of their own, which would make the game far more luck-based.
Is Minesweeper a game of pure logic or does luck play a part?
Most of a board is solvable by pure deduction, but not all of it. Researchers have shown the general Minesweeper consistency problem is NP-complete, and many boards reach a position where two or more cells are equally likely to hide a mine and no logic can separate them. At that point you must guess. Strong players minimise guessing by clearing all forced cells first and, when a guess is unavoidable, choosing the cell with the lowest mine probability.
What do the numbers on a revealed cell mean?
A number is the count of mines in the up-to-eight cells touching that cell (horizontally, vertically, and diagonally). A 1 means exactly one of its neighbours is a mine; a 3 means three are. A blank revealed cell has zero adjacent mines, which is why the board auto-opens a whole connected region of blanks at once. Reading these counts against each other is the entire deductive engine of the game.
What is the 1-2-1 pattern and why is it useful?
The 1-2-1 pattern is a row of three numbered cells reading 1, 2, 1 along the edge of the unrevealed area. It forces a fixed solution: the mines sit under the two cells beneath the 1s, and the cell beneath the 2 is always safe. Memorising a handful of these set patterns (1-2-1, 1-2-2-1, and corner reductions) lets you clear large stretches instantly instead of re-deducing each cell from scratch.
What are the standard Minesweeper difficulty levels?
The classic Microsoft presets are Beginner (a 9x9 grid with 10 mines, about 12 percent density), Intermediate (16x16 with 40 mines, about 16 percent), and Expert (a 30x16 grid with 99 mines, about 21 percent). Higher mine density means more forced guesses and faster games. World-record Expert times sit around 30 to 40 seconds, achieved with no-flag play and heavy pattern recognition.