💣 Minesweeper
Avoid all mines and reveal every safe cell to win!
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The Puzzle That Shipped With Windows (and Broke Computer Science)
Minesweeper's modern form crystallized in Microsoft's 1990 Windows Entertainment Pack — legend says to train users in precise right-clicking, the way Solitaire trained dragging. It became one of the most-played games in history, and then, remarkably, a serious research object: in 2000, Richard Kaye proved that deciding whether a Minesweeper configuration is consistent is NP-complete, tying this desktop time-killer to the P vs NP problem, the most famous open question in computer science. The game on your screen is, formally, as hard as problems get.
In practice, though, most boards yield to a handful of learnable rules — each number states exactly how many of its eight neighbors are mines, and cross-referencing those constraints solves ~90% of situations with certainty.
The Pattern Library Every Solver Memorizes
- Flag-counting, both directions. If a number already has that many flags around it, every other neighbor is safe (use "Reveal All Adjacent" to clear them at once). If its unrevealed neighbors exactly equal the remaining count, they're all mines. This one rule, applied relentlessly, clears most of any board.
- 1-2-1 against a wall of unknowns: mines sit under the two 1s; the cell under the 2 is safe. Burn it in — it appears constantly.
- 1-2-2-1: mines under the two 2s; the cells under the outer 1s are safe.
- Constraint subtraction: when two adjacent numbers share neighbors, subtract the smaller from the larger — the difference is the mine count in the non-shared cells. A 3 next to a 1 sharing two cells means the 3's exclusive cells hold exactly two mines. This is the key that opens tangled endgames.
- When you truly must guess, pick the cell with the lowest local mine density and the most open ground behind it; corners are statistically the worst gambles. The remaining-mines counter is a global constraint players forget — in endgames it often turns a guess back into a deduction.
Speedrun Culture: 3BV and the No-Flag Purists
Competitive Minesweeper is a real scene with decades of world records. Its central metric is 3BV ("Bechtel's Board Benchmark Value") — the minimum number of clicks needed to clear a board — and rankings measure how close your click count and time get to that floor. Elite players sub-40-second expert boards; many play no-flag (NF), holding all mine positions in their head because planting flags costs clicks. You don't need any of that to enjoy the game, but two habits trickle down usefully: plan clicks in batches rather than one at a time, and treat chording ("Reveal All Adjacent") as your primary clearing tool rather than a novelty.
For custom boards, mine density is the difficulty dial: the classic levels run ~12% (beginner) to ~21% (expert), and 15–20% is the sweet spot where logic dominates. Above ~25%, unsolvable-without-guessing positions multiply and the puzzle degrades into a lottery.
Frequently Asked Questions
Do I have to flag every mine to win?
No — the win condition is revealing every safe cell. Flags are memory aids (and fuel for flag-counting deductions). Skilled players often flag only where it enables a chord.
How do I flag on a touchscreen?
Tap a cell to open the quick-action menu and choose the flag icon; tap again to remove. Desktop users right-click as usual.
Can the first click hit a mine?
Mines are placed at deal time, and the game auto-reveals a safe region near the center so you start with real information. Clicking blindly outside it can still detonate — expand from the revealed border by deduction instead.
What is "Reveal All Adjacent" exactly?
The chord move: on a number whose flag count matches it, this opens all remaining neighbors in one action. It's the fastest tool in the game — and it trusts your flags completely, so a wrong flag means an instant boom.