Puzzle guide
How to solve Shakashaka
Shakashaka is a puzzle of black triangles. You put half-cell triangles into white cells so that every white space left over is a rectangle, either standing straight or tilted like a diamond. The numbers on the black cells tell you how many triangles touch them.
The rules
- You may put a black triangle into a white cell. It fills one corner, half of the cell. Or you leave the cell empty.
- A number on a black cell says how many of the cells right next to it (above, below, left, right) hold a triangle.
- The white parts that are left must all be rectangles: standing straight, or tilted like a diamond.
- Black cells stay black.
A solved puzzle
Your first moves
- Put a dot on every cell next to a 0: no triangle goes there.
- Find numbers that need every free neighbour, like a 4, or a 2 with only two free cells left. Those neighbours all get a triangle.
- Think about the white shapes: a white area may only have square corners. A sharp, pointed white corner is never allowed.
- Look for diamonds: four triangles around a point make a tilted square.
Techniques, step by step
A 0 wants no triangles
A black cell with a 0 has no triangle in any of the four cells beside it. Put a dot in each of them: they stay completely white. Those white cells then decide which way the triangles around them may lean.
A number that needs every neighbour
If a number is as big as the free cells beside it, every one of them holds a triangle. And once a number has all its triangles, the rest of its neighbours stay white with a dot. Counting this way is the first step on every board, though it does not yet tell you which corner each triangle fills.
No sharp white corners
Every white area must be a rectangle, so all of its corners are square. A triangle that would leave a pointed white tip, against a black cell, the edge, or another triangle, is in the wrong corner. That is how you pick the corner: of the four ways a triangle could lean, usually only one leaves the white space with square corners.
Read one grid point
Look at one point where four cells meet. The white space around it may only turn there by a right angle, run straight past it, or surround it completely. So the four pieces around a point can only combine in a few ways. Try them: if every way that works puts the same piece in a cell, that piece is right. Then do the same with two neighbouring points, the six cells around one edge.
The turned square
Four triangles leaning away from a common point make a tilted white square, a diamond. Bigger diamonds and long tilted rectangles are built the same way, with triangles along their edges. Once you see one side of a tilted shape, the triangles on the other sides usually follow.
Common mistakes
- Counting diagonal cells. A number counts only the four cells directly above, below, left and right of it.
- Pointed white shapes. A white area must be a real rectangle. A triangle-shaped white gap means a triangle is in the wrong corner.
- Forgetting tilted rectangles. Diamonds and tilted rectangles are allowed and are often the answer.
- Filling white cells by habit. A cell may stay completely white. Not every cell needs a triangle.
Questions and answers
Ready to play?
Count the triangles each number needs, never leave a pointed white corner, and read the board one point at a time. That is how Shakashaka's rectangles appear.