How to Play Hitori
Hitori is a masterpiece of Japanese deductive logic. Rather than filling in empty squares with numbers, you begin with a grid full of numbers and shade out the duplicates to restore balance.
🚫 No Row/Col Duplicates
In the unshaded white cells, each number can only appear once per row and column.
⬛ Black Cells Can't Touch
Shaded black squares cannot share a horizontal or vertical edge.
🌐 Connected White Network
All remaining white squares must form a single unbroken orthogonal region.
Essential Hitori Solving Techniques
- The Sandwich Rule (ABA): If the same number appears separated by one cell (e.g.
2 - 5 - 2), the middle number (5) must always be white/circled. If it were black, the two 2s would both have to be black, violating Rule 2! - Surrounding Black Cells with White: Whenever a cell is shaded black, all 4 orthogonal neighbor cells are immediately confirmed white/circled.
- Corner Traps: Avoid shading cells that would cut off a corner square, because a corner square only has 2 orthogonal exits.