About Trinairo
Fill paper charts with A, B and C. Every line needs an equal share of each letter, while double-framed squares must differ from their neighbours.
Explore 219 original puzzles across two open shelves: 106 small 6×6 charts and 113 larger 9×9 charts. Combine line counts with neighbour exclusions to work toward one complete grid.
How to play
- Goal
- Fill every square with A, B or C, balancing each row and column and respecting the marked squares.
- How it ends
- A chart is solved when every row and column contains equal numbers of each letter and every marked square differs from all its orthogonal neighbours.
- Record
- Your fastest first solve is kept for each chart; later solves are practice.
- Select an empty square, then choose A, B or C. Printed letters stay fixed.
- Each row and column needs equal numbers of all three letters: two of each on a 6×6 chart, three of each on a 9×9 chart.
- A double-framed square must differ from every square immediately above, below, left or right of it. Diagonal neighbours may match.
- Unmarked neighbours may match. Repeated rows, repeated columns and triples are allowed; this is not Takuzu.
- Pencil keeps optional candidate letters. Erase, Undo and Redo let you revise entries. The chart finishes automatically when every rule agrees.
Controls
| Input | Action |
|---|---|
| Tap / click a square, then A / B / C | Select a square and write its letter |
| Pencil / Erase | Toggle candidate notes / clear the selected entry |
| Arrow keys; A / B / C; Delete | Move the grid cursor; write a letter; erase |
| N; Z / Y; R | Toggle pencil; Undo / Redo; open Restart |
| Escape | Close a panel or return to the atlas |
Tips
- Count the missing letter When a row already has its full share of A and B, its remaining squares must be C.
- Use the marked frame Two different letters beside a double-framed square exclude both, leaving the third letter.
Good to know
Progress and Undo history save in this browser. The first clock starts on chart selection and continues through menus and Restart. Reloads, clock changes or browser suspension make an attempt local only. Later solves are practice. Large charts scroll without shrinking their squares.
Watch how to play
Questions
Is this the same as Takuzu?
No. Trinairo uses three letters and marked-square neighbour exclusions. Repeated lines and three matching letters in a row are allowed when the actual rules hold.
Must diagonal neighbours differ?
No. Only orthogonal neighbours of a marked square must differ from it.
