Minesweeper Rules — Complete Guide

The Board

A Minesweeper board is a rectangular grid of cells. Each cell is initially hidden. Beneath the surface, a fixed number of mines are randomly distributed across the grid (with the guarantee that the first cell you click is never a mine). The remaining cells are safe — they either border at least one mine and display a number, or they border no mines and display nothing (blank).

Standard dimensions are 9×9 (Beginner, 10 mines), 16×16 (Intermediate, 40 mines), and 30×16 (Expert, 99 mines). Custom boards with arbitrary dimensions and mine counts are also possible.

Mines

Mines are the hazards of the game. They are invisible until you either click on one (ending the game) or successfully complete the board (at which point all mine locations are revealed). The total number of mines is always shown in the mine counter at the top of the board.

A mine occupies exactly one cell. Mines do not "spread" or have blast radii — only the exact cell that contains the mine is dangerous. Clicking any safe cell adjacent to a mine simply reveals its number; only clicking the mine cell itself causes a loss.

Numbers

When you reveal a safe cell that is adjacent to one or more mines, the cell displays a number from 1 to 8. This number is the exact count of mines in the eight neighboring cells (horizontally, vertically, and diagonally adjacent). Numbers are the primary source of information in Minesweeper — all logical deductions flow from them.

A blank cell (no number) means none of its eight neighbors contain a mine. Revealing a blank cell triggers an automatic cascade: the engine reveals all connected blank cells and their numbered borders simultaneously, potentially opening a large section of the board.

Flags

Right-clicking an unrevealed cell places a flag (🚩) on it. Flags are markers that communicate your belief that a mine is hiding there. They serve two purposes: they prevent accidental clicks on cells you've identified as mines, and they enable chording (see below).

The mine counter decrements by 1 for each flag placed, giving you a running tally of how many mines remain unaccounted for. Importantly, the game does not check whether your flags are placed correctly — you can flag a safe cell, and the counter will still decrement. Only winning or losing reveals the truth.

On some implementations a second right-click cycles through a question-mark state (?) before removing the flag. On this site, right-clicking toggles directly between flagged and unflagged.

Chording

Chording is an advanced mechanic that speeds up play significantly. When a revealed number cell has exactly as many adjacent flags as its number value, you can chord-click it to instantly reveal all remaining non-flagged neighbors.

For example: a "2" cell with two adjacent flags can be chorded to reveal its remaining neighbors in a single click. If all your flags on that cell are correctly placed, all revealed neighbors will be safe. If any flag is wrong (placed on a safe cell), the chord will detonate a mine and end the game.

This is why flag accuracy matters so much at higher levels. A misplaced flag doesn't just waste time — it makes chording on that cluster impossible until you correct it.

Win Condition

You win when every cell that does not contain a mine has been revealed. The game does not require you to flag all mines — only to clear all safe cells. When the last safe cell is revealed, the game ends immediately with a win, your timer stops, and your time is recorded as a personal best if it qualifies.

On completion, all mine locations are shown — flagged mines appear with a flag, unflagged mines appear as revealed bomb icons. If you flagged a safe cell (a wrong flag), it's shown with an X through it.

Lose Condition

You lose the moment you reveal a cell containing a mine. The game ends immediately, regardless of how many safe cells remain. All mines on the board become visible, and the mine you clicked is highlighted to indicate your fatal click.

A loss triggered by incorrect chording (chording a number when a neighbor flag is misplaced) follows the same rule — the mine underneath the incorrectly flagged cell is revealed, and the game ends.

First-Click Safety Rule

The standard rule in modern Minesweeper implementations, including this one, is that the first cell you click is always safe. The board generates mine placements only after your first click, ensuring you never detonate a mine immediately.

Some implementations guarantee not just that the first cell is safe, but that a cascade opens from the first click, so the game always starts with some information revealed. This site uses this stronger guarantee.

No-Guess Mode

Standard Minesweeper sometimes places mines in positions where the only way to proceed is to guess — a 50/50 situation with no additional logical information available. Skilled players accept these guesses as part of the game, but many players find them frustrating.

No-Guess mode (available on this site) generates boards that are guaranteed to be solvable by logic alone, from start to finish, with no guessing required. The generation algorithm rejects any mine layout that would create an unavoidable guess. This produces a slightly different game experience — every bomb location is logically deducible — but it also means the boards are not identically distributed to classical Minesweeper and times are not directly comparable.

Timer

The timer starts on your first click and stops the moment you reveal the last safe cell (win) or click a mine (loss). Time is displayed in seconds to two decimal places. The official measure of skill in competitive Minesweeper is time, though derived metrics like 3BV/s (board complexity per second) and efficiency are also tracked on the leaderboard.