Takuzu
Fill the grid with two symbols so that every row and column obeys three simple rules.
Rules
- No triples: Three consecutive identical symbols in a row or column are not allowed.
- Equal count: Each row and column must contain exactly the same number of ● and ○.
- Unique lines: No two rows may be identical, and no two columns may be identical.
Pre-filled cells (shown in bold) are locked and cannot be changed. The puzzle is solved when every cell is filled and all three rules are satisfied.
The context row below the grid shows the current cursor row and column counts for
0 and 1. Count chips invert when a line reaches its quota and turn into an
error chip if a line goes over quota.
Controls
| Key | Action |
|---|---|
Arrows / wasd / hjkl |
Move cursor |
Mouse left-click |
Move to a cell, or cycle the current editable cell |
z / 0 |
Place ● (filled) |
x / 1 |
Place ○ (open) |
Backspace |
Clear cell |
Ctrl+H |
Toggle full help |
Ctrl+R |
Reset puzzle |
Escape |
Return to main menu |
Tips
- Sandwich rule: If two identical symbols are next to each other, the cells on either side must be the opposite symbol. For example, ● ● means the neighbours are both ○.
- Count what you have: When a row or column already has its full quota of one symbol, the context row marks that count so every remaining empty cell in that line must be the other symbol.
- Avoid the third: Before placing a symbol, glance one and two cells ahead in each direction. If placing it would create three in a row, it has to be the other symbol.