What is Shakashaka?
Shakashaka is played on a grid of black and white cells. You may place a black right-triangle in any white cell, choosing one of four orientations, so that the triangle covers exactly half the cell along a diagonal. A white cell can also be left completely empty.
Two rules govern your choices. First, every region of remaining white space must be a rectangle — either an ordinary upright rectangle or a rectangle rotated 45 degrees into a diamond. Second, a number written in a black cell states exactly how many of its orthogonally adjacent cells contain a triangle.
- Each white cell is empty or holds one of four right-triangles.
- The triangle covers half the cell along a diagonal.
- Every leftover white region must be a rectangle.
- Rectangles may be upright or tilted at 45 degrees.
- A number in a black cell counts triangles in its four neighbours.
Why a lone triangle is never allowed
A single triangle in an otherwise empty area leaves a triangular piece of white space behind, and a triangle is not a rectangle. So triangles can never stand alone — they always come in groups that close the white space back into rectangles.
The smallest legal group is a diamond made of four triangles meeting at a corner, or a pair of triangles that square off the end of a white strip. Whenever you place one triangle, ask what other triangles it forces nearby to keep every white region rectangular.
Reading the number clues
The numbers do a lot of the work. A 0 means none of that black cell's neighbours may hold a triangle, so those cells are either empty or, if they need a triangle for the rectangle rule, the layout around them has to change. A 4 means all four neighbours are triangles.
Most useful are the small and large numbers near the edges and corners, because edge cells have fewer neighbours. A 2 next to a corner, where the black cell has only two neighbours, fixes both of them as triangles at once.
- 0: none of the four neighbours is a triangle.
- 4: all four neighbours are triangles.
- Edge and corner clues are strongest — fewer neighbours to satisfy.
- Combine clues with the rectangle rule, not in isolation.
- A black cell with no number gives no triangle count, just a wall.
How to play here
Click a white cell to drop in a triangle; click again to spin it through the four orientations and then back to empty. Right-click steps backwards through the orientations. There is nothing to type — every move is a single click.
Triangles that do not match the solution are highlighted so you can correct course, and the puzzle completes the moment every white area is a rectangle and every number is satisfied. Use Hint to place one correct triangle, or Clear to start the shapes again.
- Left-click a white cell to cycle triangle, then empty.
- Right-click to cycle the orientations backwards.
- Wrong triangles are highlighted in red.
- Use Hint for one correct cell, or Clear to reset.
- Solve reveals the finished arrangement.
Difficulty levels and why play online
Easy Shakashaka uses a 5x5 grid where the diamonds are small and the number clues lead you by the hand. Medium moves to 6x6, Hard to 7x7, and Expert to a 8x8 grid where the tilted rectangles get larger and the deductions chain further.
Playing online keeps the geometry honest: triangles snap cleanly into place, wrong tiles show in red, and your progress saves locally in your browser. Every grid is generated and checked for a single solution, so a Shakashaka always rewards careful shape logic over guessing.
- Easy: a 5x5 grid to learn the diamonds.
- Medium: a 6x6 everyday challenge.
- Hard: a 7x7 grid with larger tilted rectangles.
- Expert: an 8x8 grid for confident solvers.