The rules
- White
- Black
- Black out cells until every number counts what it sees.
- Black out some cells. A numbered cell is never blacked out.
- A number says how many white cells it sees in a straight line — up, down, left and right — counting its own cell and stopping at the first black cell or the edge of the board.
- No two black cells ever share an edge. Corners are fine.
- All the white cells form one connected area.
- Two mistakes are pointed out as you play: a number that can no longer count out, and two black cells side by side. White cells cut off from the rest are not marked — so a full board with no warnings on it can still be wrong.
- Tap a cell to black it out, tap again to clear it. Press and hold to mark it white instead. Drag to black out a run of cells.
- Every puzzle here is solvable by reasoning alone. You never have to guess.
- Got it
How to play here
Three ways to play
Campaign
Chapters that start gently and bring in one new idea at a time.
Daily puzzle
A new board every day, the same for everyone. Solve every one in a month and that month's trophy is yours.
Endless
Keep going as long as you like, in Easy, Medium, Hard and Expert.
Common questions
Is Conspectus free?
Yes. You can play here without paying and without an account. Ads keep the lights on.
Where is my progress saved?
In this browser, on this device. If you clear the site data, your progress goes with it. A free Solvarium account keeps it safe.
Does it work on a phone or tablet?
Yes. It runs in any current browser on phones, tablets and computers, and the board resizes to fit the screen.
Does every puzzle really have one solution?
Yes. Every board goes through a solver before it ships, and anything with more than one solution is thrown out.