Minesweeper

A revealed number is the count of mines in the eight surrounding cells.; A cell with no adjacent mines shows blank and cascades, auto-revealing its neighbours until numbers are reached.; If a number already touches that many flags, its remaining neighbours are provably safe.

Beginner: 9×9 grid, 10 mines.; Intermediate: 16×16 grid, 40 mines.; Expert: 30×16 grid, 99 mines.

Uncover every cell that does not contain a mine. Flagging is an aid only — the game is won by clearing safe cells, not by flagging mines correctly.

Clicking a satisfied number — one with the correct count of flags around it — uncovers all its remaining neighbours at once. This is where most of the speed in expert play comes from, and misplacing a flag beforehand makes it instantly fatal.

There is no score. The metric is time to clear the board, recorded separately per difficulty.

No governing body exists; competitive Minesweeper is organised around community ranking sites and their conventions: Standard board sizes (beginner, intermediate, expert) are the only recognised categories for records.; Timing runs from first click to final safe cell.; No-guess boards are usually...

In the standard implementation the first click is always safe; the board is generated or adjusted around it. Older versions did not guarantee this, which is why very old Minesweeper could end on move one.