Play Shakashaka Online — Free
Place right triangles in white cells so that all remaining white space forms rectangles. Numbers in black cells tell you how many adjacent white cells contain triangles.
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About Shakashaka
Shakashaka is a Japanese puzzle where you place right triangles in the white cells of a grid that also contains numbered black cells. Each triangle half-fills its cell (a NE triangle fills the upper-right half, for example). The goal: every white region not occupied by a triangle must form a complete rectangle, and each numbered black cell must be adjacent to exactly as many triangles as its number indicates.
The interaction between triangle placement and rectangle formation is the key challenge. Two adjacent triangles must combine into a complete rectangle — an upper-right triangle next to a lower-left triangle in the adjacent cell forms a complete square. Tracing these geometric pairings across the grid requires spatial reasoning unlike any other puzzle type.
Shakashaka is inventive and visually distinctive. Watching triangles click into rectangular pairs as you solve gives it a uniquely satisfying geometric quality. It’s one of the most original puzzle concepts to emerge from Japan in recent years, offering a fresh experience for veterans of grid-logic puzzles.
Start with numbered black cells at 0 (no adjacent triangles) and at maximum (all orthogonal neighbors contain triangles). These immediately lock down large areas of the grid and establish the geometric pairs that propagate outward.
Frequently asked questions
What is Shakashaka?
Shakashaka is a logic puzzle where you place right triangles in white cells. When filled, all remaining white space (not covered by triangles) must form rectangles. Numbers on black cells tell you how many of their adjacent cells contain triangles.