Minegrid

How It Works

How to play: Left-click to reveal a cell. Right-click to place or remove a flag on a suspected mine. Your first click is always safe — mines are placed after you click.

Chord-click: Left-click a revealed number cell when you've flagged exactly that many neighboring mines to auto-reveal the remaining neighbors. Use this to clear areas quickly once you're confident in your flags.

Strategies: The "1-1 pattern" occurs when two adjacent numbered cells share the same unrevealed neighbors — the difference in their counts reveals which cells are safe. Corners and edges reduce the number of possible mine positions, making them easier to deduce.

This style of mine-sweeping game was popularized by Microsoft Windows in 1990. The game is NP-complete in the general case — determining whether a valid mine placement exists for a given board state is as hard as any problem in NP.