Minesweeper Rules
A reference, not a tutorial. If you want the rules explained by playing through a game, use the beginner walkthrough instead.
Objective
Reveal every cell that does not contain a mine. Nothing else is required.
Board configurations
| Difficulty | Width × Height | Cells | Mines | Density | Safe cells |
|---|---|---|---|---|---|
| Beginner | 9 × 9 | 81 | 10 | 12.3% | 71 |
| Intermediate | 16 × 16 | 256 | 40 | 15.6% | 216 |
| Expert | 30 × 16 | 480 | 99 | 20.6% | 381 |
Notes:
- Expert is 30 wide by 16 tall. Written as 16×30 in some sources; the board is landscape either way.
- These three are the decades-old standard used for record keeping. Custom boards are valid but not comparable.
- Density is the main driver of difficulty. Expert's 20.6% is where forced guesses become common.
Cell states
| State | Appearance | Can be clicked? | Notes |
|---|---|---|---|
| Covered | Blank raised tile | Yes | Unknown contents |
| Revealed, numbered | Digit 1–8 | Chord only | Digit = adjacent mine count |
| Revealed, empty | Flat blank tile | No | Zero adjacent mines; triggers cascade |
| Flagged | Flag marker | Flag toggle only | Player annotation; blocks opening |
| Mine (revealed) | Mine marker | — | Only shown after a loss |
Numbers
| Rule | Detail |
|---|---|
| Meaning | Count of mines in the up-to-8 cells directly surrounding it |
| Range | 1–8 |
| Adjacency | All 8 directions, including diagonals |
| Corner cell | 3 neighbours — max possible number is 3 |
| Edge cell | 5 neighbours — max possible number is 5 |
| Interior cell | 8 neighbours — max possible number is 8 |
| Zero | Displayed as blank, never as "0" |
Controls
| Action | Mouse | Touch | Keyboard (this site) |
|---|---|---|---|
| Reveal cell | Left click | Tap | Space / Enter |
| Toggle flag | Right click | Press and hold (~0.5s) | F |
| Chord | Both buttons, or middle click, or double click | Tap a revealed number | Space / Enter on a revealed number |
| Move cursor | — | — | Arrow keys |
| Restart | Click reset button | Tap reset button | — |
Win condition
| Condition | Every non-mine cell is revealed |
| Flags required | None. A game can be won with zero flags placed |
| Incorrect flags | Do not prevent a win, as long as they never blocked a safe cell |
| On win | Timer stops; board locks; reset button shows ✓ |
| Remaining mines | Stay covered. You never have to open or flag them |
Loss condition
| Condition | A mine is revealed |
| On loss | Timer stops; all mine locations shown; incorrectly flagged cells marked as wrong |
| Flagged mine | Cannot be triggered — flags block reveal |
| Undo | None. A loss is final |
Flag rules
| Rule | Detail |
|---|---|
| Purpose | Player annotation and a prerequisite for chording |
| Effect on win | None — flags are not part of the win condition |
| Correctness feedback | None during play. A wrong flag looks identical to a right one |
| Blocks revealing | Yes — a flagged cell cannot be opened until unflagged |
| Blocks cascade | Yes — flood fill stops at flagged cells |
| On revealed cells | Not allowed |
| Quantity limit | None. You may place more flags than there are mines |
| Removal | Toggle off with the same input |
Mine counter
| Rule | Detail |
|---|---|
| Displays | Total mines minus flags placed |
| Counts | Flags only — not mines correctly identified |
| Reaching 000 | Means you've placed that many flags. Does not mean you've won |
| Negative values | Possible when flags exceed mine count; shown as e.g. -05 |
| Reliability | Only as accurate as your flags |
Cascade (flood fill)
| Rule | Detail |
|---|---|
| Trigger | Revealing a cell with zero adjacent mines |
| Behaviour | Auto-reveals neighbours, spreading outward |
| Stops at | Numbered cells (revealed, not expanded past) and flagged cells |
| Numbered cells | Opened by the cascade, but do not propagate it |
| Risk | Zero — a cascade can never open a mine |
Chord rules
Chording opens all unflagged neighbours of a revealed number in one action.
| Condition | Requirement |
|---|---|
| Target cell | Must be revealed and show a number 1–8 |
| Flag count | Adjacent flags must exactly equal the number |
| Too few flags | No effect — board unchanged |
| Too many flags | No effect — board unchanged |
| Flags correct? | Not checked. Chording with a misplaced flag opens a mine and loses |
Chording is a shortcut for actions you could perform individually — it grants no information you didn't already have. Tactical usage is on the strategy page.
First click
| Rule | Detail |
|---|---|
| Classic (1990) | Could hit a mine immediately |
| Modern standard | First click is guaranteed safe |
| This site | First click is safe and guaranteed to have zero adjacent mines, so it always cascades |
| Mechanism | Mines are generated after the first click, excluding that cell and its 8 neighbours |
Implementation detail: how the engine works.
Timer
| Rule | Detail |
|---|---|
| Starts | On first click — not on page load |
| Stops | On win or loss |
| Resolution | Whole seconds |
| Display cap | 999 |
| Pause | Not supported |
Commonly misunderstood rules
"You must flag every mine to win." False. The win condition is revealing all safe cells. Flags are optional throughout.
"The game tells you when a flag is wrong." False. There is no feedback during play. Incorrect flags are only marked after a loss.
"Getting the counter to 000 wins the game." False. The counter tracks flags placed, not mines found. Ten flags on ten empty cells reads 000 with zero progress.
"The first click can kill you." False on this site and on most modern implementations. True in the original 1990 version.
"Every board can be solved with logic." False. Boards are randomly generated and not validated for solvability. Some positions require a genuine guess — see why some boards are unsolvable.
"Numbers only count horizontal and vertical neighbours." False. All eight surrounding cells count, diagonals included. This is the single most common beginner misreading.
"Chording is safe because the game checks it." False. The game verifies only that the flag *count* matches the number, never that the flags are on real mines.
"A cascade might open a mine." False. Cascades only propagate from cells with zero adjacent mines and cannot reach a mine.
Rule variants
| Variant | Difference |
|---|---|
| No-guess mode | Generator rejects boards requiring a guess. Not standard |
| Question marks | Optional ? annotation state, cycled after flag. Disabled here |
| Flagless / NF | Self-imposed style: no flags, chord-free. Legal under standard rules |
| Custom boards | Arbitrary dimensions and mine counts. Not comparable for records |
| Multi-mine cells | Cells holding >1 mine. A different game |
Rules confirmed. Next: the patterns that resolve most positions, or play a board on the home page.