Signal Sweep

Reading the board in Signal Sweep

Sixty-four cells, ten hazards, one guaranteed opening

The grid is eight by eight with ten hazards hidden in it, so just under sixteen percent of the board is dangerous. A revealed safe cell shows a number: how many of its up-to-eight surrounding cells contain a hazard. A blank means zero, and blanks automatically cascade outward to reveal their neighbours.

Hazards are not placed until after your first click. The game excludes your chosen cell and all of its neighbours from the placement pool, which guarantees the opening reveal is not only safe but always opens into a blank region rather than a lone number. There is no such thing as a first-click loss.

You win by revealing all 54 safe cells. Flagging is a bookkeeping aid for you rather than a win condition — flagging all ten hazards does not by itself end the game.

Every number is a complete constraint

A number tells you exactly how many hazards sit among its unrevealed neighbours, which makes two deductions available immediately and constantly. First: if a number equals the count of unrevealed cells around it, every one of those cells is a hazard. Second: if a number equals the count of flags already around it, every remaining unrevealed neighbour is safe and can be revealed without risk.

Those two rules alone solve most of a board. When they run out, use the subtraction pattern on adjacent numbers. If a 1 and a 2 sit side by side and share some unrevealed neighbours, the cells belonging only to the 2 must account for the difference — often pinning a hazard exactly where neither number could identify it alone.

Work the edges and corners first when you have a choice. A corner cell has only three neighbours and an edge cell five, so each number there constrains a much smaller set of possibilities than the eight-neighbour numbers in the open middle.

Board odds worth knowing

With ten hazards among 64 cells, a blind click on an untouched board is dangerous about one time in six. That average is misleading once play begins, though, because information concentrates: the cells adjacent to a high number are far more dangerous than average, and the cells adjacent to a satisfied number are entirely safe.

The practical consequence is that a guess is almost never as risky as it feels, provided you guess in the right place. When you genuinely must guess, pick the cell furthest from any high number rather than the one that simply looks isolated.

Common mistakes

Three of these are habits carried over from versions of the game that behave differently.

• Opening in a corner to be cautious. It is the worst opening square: three neighbours means the smallest possible first cascade and the least information from a guaranteed-safe click.
• Flagging everything you suspect. Flags are a note to yourself, not a claim the game validates. A wrong flag propagates into every deduction you make afterwards.
• Forgetting the satisfied-number rule. Once a number has its full count of flags around it, every other neighbour is provably safe — that is free progress people routinely leave on the board.
• Assuming flagging all ten hazards wins. The win condition is revealing all 54 safe cells; correct flags alone do not finish the board.

What is different about this version

Hazard placement happens after your first reveal and deliberately excludes that cell and its entire neighbourhood, so the opening move is guaranteed to be both safe and productive. Many implementations only protect the clicked cell itself, which still permits an opening that reveals a bare number and no cascade.

Flagging is a mode toggle rather than a right-click requirement, so the whole game is playable with single taps or single clicks. That is what lets it work identically on a touchscreen, a trackpad, and a keyboard without a hidden second input.

Written by the Silverweb Games team from this game’s own implementation. Last reviewed July 31, 2026.