LOGIC PUZZLE
No-guess Minesweeper
Classic minesweeper has one flaw: sooner or later it puts two indistinguishable squares in front of you and makes you lose on bad luck. Not here. Every grid goes through a solver before it reaches you, and if it does not close by reasoning it gets thrown away. If you step on a mine, the mistake is yours — not the dice.
Mouse: left click digs, right click plants a flag, clicking a number that is already satisfied opens its remaining neighbours. Touch: tap to dig, long press to flag. Spacebar swaps tools.
How to play
Mines are hidden under the grid. Every square you uncover shows how many mines touch that square, diagonals included: from 0 to 8. If the number is zero the area opens by itself up to the first numbers.
Your job is not to uncover everything: it is to uncover every square without a mine. Flags are for you, to remember where you have already worked out that a mine sits.
The first square is always safe and always opens an area: the field is built around your first click, not before it.
The three moves that almost always suffice
The direct count
A 1 that already has a flag beside it has no others: all its remaining covered squares are safe. Conversely, a 3 with exactly three covered squares around it has all of them mined. That is 90% of the moves in a game.
The 1-2-1 pattern
Three numbers in a row reading 1 2 1 along an uncovered edge: the mines sit under the two 1s, never under the 2. The reason is that the constraint of the 2 contains those of the two 1s, and the difference between the sets resolves itself. It holds in every direction.
Subtracting between neighbours
When two numbers share some covered squares, look at the difference: if a 2 and a 1 share two squares, the extra square belonging to the 2 is certainly a mine. This is the general form of the pattern above, and it is also what the solver uses to decide whether a grid is acceptable.
The options
- Difficulty — 9×9 with 10 mines, 16×16 with 40, or 20×16 with 60.
- Lives — 1 (the classic: one mine and it is over), 3, or unlimited. On unlimited the mine is flagged and you carry on.
- Auto flags — when a mine becomes certain, the flag plants itself.
- Hints — uncover a random safe square.
- Resume — the game saves itself: close the tab and find it where you left it.
Frequently asked questions
What does «no-guess» mean?
It means you will never face two indistinguishable squares and have to pick at random. Every grid is simulated by a solver that uses deduction only: if the solver gets stuck, the grid is discarded and another one is generated. Traditional minesweeper does not run this check, which is why you sometimes lose without having done anything wrong.
Can the first square be a mine?
No. The field is generated after your first click, excluding that square and the eight around it: a game always starts with an open area, never with an isolated number.
Is it free?
Yes, it plays free in your browser. No sign-up, no account, no advertising and no data collection: the whole game runs on your device.
Does it work on a phone?
Yes. A tap digs, a long press plants a flag, and the buttons at the bottom let you switch tool, adjust the zoom or fit the grid to the screen.
Is progress saved?
Yes. The game in progress is kept in your browser's local storage, so you can close the tab and pick up where you left off. The save never leaves your device and is dropped once the game ends.
How it is built
The game is a single page, no libraries and no backend. The part that matters is not the minesweeper — that is an afternoon of work — but the filter that runs before it.
The solver reasons on three levels, from the cheapest to the most expensive. The first is the count on a single square. The second compares pairs of constraints: if the covered squares of one number are a subset of another's, the difference between the two resolves itself — the rule that formalises the 1-2-1 pattern. The third, when the other two stall, enumerates every mine arrangement compatible with the frontier and keeps only what holds in all of them; it is capped at 22 squares, beyond which it would cost too much.
If the grid does not close after all three, it gets thrown away. Measured on random grids: 85% survive on easy and only 28% on hard, and the generator tries 2.5 of them on average before finding a good one. That discarded 72% is exactly the set of games that would have made you lose on bad luck.
It comes out of the same way of working I apply to products: Miraviso is a real case, and if you need a hand with something similar, start here.