The rules of Démineur

The goal

Open every square that does not hide a mine, without ever opening one that does. The grid size and number of mines depend on the selected level:

The numbers

An open square shows the number of mines among its 8 neighbors: left, right, above, below, and in the four diagonal directions. An edge square has fewer neighbors, and a corner square has only three. A square with no neighboring mines stays blank: its value is zero.

Cascading openings

When an open square has a value of zero, none of its neighbors contains a mine: the app automatically opens them all, and repeats this for each newly opened square with a value of zero. A single tap can therefore open a large area bordered by numbers.

The first tap is protected

The app only places the mines on the first tap, and never within the 3 × 3 square area centered on the tapped square. That square therefore always has a value of zero, and the app opens at least that square and all its neighbors. In the grid below, generated by the app, the first tap (the square outlined in brown) opened only this square area: 9 squares.

In a corner, the protected square area is cut off by the edges, leaving just four squares.

Flags

A flag marks a square you think contains a mine. There are two ways to place one:

• long-pressing a hidden square places or removes a flag once the game has started;
• flag mode: the selector in a corner of the screen switches from number mode to flag mode; each tap then places or removes a flag.

A flagged square does not open when tapped: the flag prevents accidental taps. The mine counter shows the number of mines minus the number of flags placed. The app does not limit flags: if you place too many, the counter goes below zero. There is no question mark.

Chording: opening a number's neighbors

Tapping a number that is already open opens all its hidden neighbors at once, on one condition: there must be exactly as many flags around it as the number's value. Otherwise, nothing happens. If any of these flags is wrong, chording opens a mine and the game is lost.

• hidden cell
• open cell
• ⚑ flag
• number used
• deduced safe cell
• deduced mine

Here, the number in column 4, row 3 already has as many flags around it as its value: tapping it opens its last hidden neighbor, 1 safe square.

Winning and losing

• You win as soon as all squares without mines are open, even if some mines are still unflagged.
• You lose as soon as a mine is opened, either by tapping or by chording.

The app does not award points: it measures time. The timer starts on the first tap and stops when paused, in menus, and at the end of the game. For each grid size, the statistics record games played and won, streaks, and best times.