What this game is
Minesweeper is not about luck, it is about deduction. The field is covered, mines are hidden underneath, and the only source of information is the numbers on the cells you have already opened.
Every number says the same thing: how many mines sit among its eight neighbours. On its own that means almost nothing, but two adjacent numbers together often give an exact answer — this cell is safe, that one is a mine. A game is a chain of such small proofs, built along the border between the opened and the covered.
Rules
- The field is covered and holds a known number of mines. The counter beside it shows mines minus flags, and below it runs the clock.
- A left click opens a cell. The digit inside counts the mines among its eight neighbours, diagonals included.
- A cell with no mines around it opens empty and takes its whole connected region with it, out to the digits that fence the region in.
- The first click is always safe: the mines are laid only afterwards, and neither the clicked cell nor any of its eight neighbours may carry one — so the opening move always uncovers a region.
- The right button, Ctrl+click or a long press on a touch screen sets and clears a flag. A flagged cell cannot be opened.
- Clicking an already opened digit that is surrounded by exactly as many flags as it shows opens all its remaining neighbours at once. If even one of those flags was wrong, you blow up.
- Open every cell without a mine to win: the remaining mines are flagged for you and your time is shown.
- Open a mine and you lose. The field is uncovered, and flags placed on empty cells are shown as crossed-out mines.
How to play better
- Work the border, not single cells. The only useful digit is one that still has covered neighbours.
- Two simple rules carry most of a game. If a digit has exactly as many covered neighbours as it shows, all of them are mines. If it already has that many flags around it, every other neighbour is safe.
- When a single digit says nothing, compare two of them. If the covered cells of one lie entirely inside those of the other, subtract: the difference tells you how many mines hide in the leftover strip.
- Learn the 1-2-1 pattern along a wall: the mines sit under the ones and the cell under the two is clean. Patterns save more time than fast clicking ever will.
- The mine counter is evidence too. Late in a game it often settles a fork that the digits alone cannot.
- Sometimes the logic really does run out and you have to guess. Then pick the cell touched by the fewest digits: it has the better chance of being empty.
A bit of history
Minesweeper had ancestors long before Windows. Mainframes of the 1970s already ran games in which you crossed a field of invisible mines guided by numeric hints, and in the 1980s the same idea spread to home computers — Mined-Out from Quicksilva (1983), among others.
The Minesweeper everybody knows was written by two Microsoft employees. Curt Johnson made the game for OS/2 and Robert Donner ported it to Windows. It shipped in 1990 inside the Microsoft Entertainment Pack, and from 1992 it came with Windows 3.1 as standard, taking the place of Reversi. That is how a minefield ended up on tens of millions of desktops.
The game has a mathematical biography as well. In 2000 Richard Kaye published a proof in The Mathematical Intelligencer that deciding whether any arrangement of mines is consistent with a shown field is NP-complete. In plain terms, Minesweeper has no fast general solver — so the feeling that a position sometimes hits a wall is well founded.
This version follows the applet that ran on this site from 2005: the same three classic fields, the guaranteed safe first click and the open-by-flags shortcut on a digit. Minesweeper is the only solitaire among the games here, so in the site-wide score a cleared field counts as your win and a detonation as the computer's.
About the levels
Here a level is not the strength of an opponent. There is no opponent at all: the computer thinks about nothing and adapts to nothing, it only scatters the mines at random after your first click. All that changes is the size of the field and the density of the mines.
Beginner is 9×9 with 10 mines, about twelve per cent of the cells. A short game, and almost always solvable by logic alone.
Intermediate is 16×16 with 40 mines, about sixteen per cent. Fewer open regions, more border, and noticeably longer reasoning.
Expert is 16×30 with 99 mines, about twenty-one per cent. The field is wider than a phone screen, the regions are small, and positions where logic runs out and only a guess is left turn up regularly. That is where most games are lost.