How to play Shadeout
Shadeout is a daily number shading puzzle. You start with a grid full of numbers and shade some of them until no number repeats in any row or column. A puzzle takes one to six minutes.
The rules
- No repeats. Among the tiles left showing, every number appears at most once in each row and each column.
- Shaded tiles never touch side by side. They may meet at a corner.
- One group. All the tiles left showing must connect to each other through their sides, so no tile or patch of tiles is cut off by shading.
- Shade only repeats. A tile is shaded to hide a repeat, so every shaded number still shows once somewhere in its row or column.
Every puzzle has exactly one answer, and you can always reach it by logic alone.
Controls
- Tap once to shade a tile.
- Tap twice to circle it instead, your note that this number stays showing. A third tap clears the tile.
- Drag across tiles to circle several at once. Dragging from a marked tile clears instead.
- On a keyboard: arrow keys move, Space cycles a tile, S shades, C circles, Backspace clears.
- With Auto circles on in Settings, the tiles beside a shaded tile get a dashed circle, since they can never be shaded.
- Hint highlights the next step you can prove and explains why.
- Broken rules show up right away: shaded tiles that touch get a red frame, a number circled twice in one line turns red, and tiles cut off from the rest get a dotted red outline.
Eight techniques that solve every board
Every Shadeout puzzle can be finished with the moves below. Easy puzzles need only the first six. Medium puzzles add a short what-if check. Hard puzzles need the longer what-if at least once.
1. Shade the twins
Once you know a number stays showing, every copy of it in the same row and column must be shaded. Circle tiles as you prove them, then shade their twins.
2. Circle the neighbors
Shaded tiles never touch side by side, so the up to four tiles beside a shaded tile all stay showing. Circle them, then use technique 1 on each of them. These two moves feed each other through most of a puzzle.
3. Numbers that are already alone
A number with no copy in its row or column has nothing to hide, so it always stays showing. The same holds later in the puzzle once every other copy in its lines has been shaded.
4. The sandwich
Look for the same number on both sides of one tile, like 3 1 3 in a row. If the middle tile were shaded, neither 3 could be shaded next to it, so both 3s would show. That breaks the first rule, so the middle tile stays showing.
5. The side-by-side pair
Two equal numbers next to each other, like 2 2, can't both show and can't both be shaded, so exactly one of them is shaded. That one already hides the repeat, so any other 2 in the same line must be shaded. A run of three, 2 2 2, follows at once: both ends are shaded and the middle stays.
6. Keep it connected
Before you shade a tile, check that it doesn't wall off part of the board. A tile that is the only link between two areas must stay showing. Corners and edges are where this bites first: two shaded tiles that meet diagonally around a corner tile would cut it off.
7. What if, one step
Pick a tile and imagine it shaded. Its neighbors would have to show, and their twins would be shaded. If that quick follow-up already makes two shaded tiles touch, leaves a number showing twice, or cuts the board apart, the tile stays showing. The same works the other way round: imagine a tile showing and see whether its shaded twins clash.
8. What if, followed through
On hard boards, make the same guess but keep going with every technique above, sandwiches and pairs and connection included, until something breaks. If it does, the opposite is true. Start with tiles beside a pair or in a crowded corner, where the chain stays short.
Questions
When does a new puzzle come out?
At midnight in your own time zone. The board grows through the week, from 5×5 on Monday to 8×8 on Saturday and 9×9 on Sunday.
Do I need an account?
No. Your streak, times and progress are saved in this browser. Clearing browser data removes them.
Do I have to circle the tiles I keep?
No. Circles are notes for you. The puzzle is solved the moment the right tiles are shaded.
Does using a hint break my streak?
No. Your result just shows how many hints you used.
Is Shadeout the same as Hitori?
The rules come from a classic Japanese pencil puzzle known as Hitori. Shadeout has its own boards made by our own generator, a new puzzle every day, 300 practice puzzles and step-by-step hints.
Can a puzzle need a guess?
No. Before a puzzle is published, a solver works through it with the techniques above, step by step, and a separate checker confirms it has exactly one answer. If either fails, the puzzle is thrown away.