The mine-count technique says: when every mine is flagged, everything still hidden is safe; and when the hidden squares left are exactly as many as the mines left, they’re all mines. It’s the one technique that uses the counter instead of the numbers, and it’s for the end of a game.
This is the fifth of the Minesweeper techniques.
The rule
- Read the counter: the mines left, if your flags are right.
- If it’s 0, open every hidden square.
- If it equals the number of hidden squares, flag them all.
In a real game
On the Expert board every technique page follows, it’s the very last move, step 215. All 99 mines are flagged, and one square is still hidden: the bottom-left corner. No number touches it, because its three neighbours are all mines, so none of the other techniques can say anything about it. The counter can: no mines left, so it’s safe.
How often you’ll need it
Rarely: on 1 of 200 Beginner boards, 2 Intermediate and 1 Expert. But when a square is walled in by mines like this one, nothing else will do.