An example 12×12 Sudoku: twelve symbols fill every row, column and 3×4 box (a few 1-9 shown).
12×12 Sudoku is a twelve-by-twelve grid divided into 3×4 boxes, filled with the digits 1-12. Each row, column and box must hold all twelve values once. It is one of the friendlier large formats - bigger and more absorbing than a 9×9, but built on exactly the same logic.
The rule: 1-12 in every row, column and 3×4 box
Fill the grid so no value repeats in any row, any column or any 3×4 box (three cells tall, four wide). A single box already holds a full set - below, one 3×4 box is filled with 1 through 12 to show the range you work with.
One 3×4 box holds all twelve values (1-12). The full grid has twelve such boxes.
Same logic, more to track
A 12×12 is not conceptually harder than a 9×9 - the techniques are identical - but there is more to hold in your head: twelve candidates per cell and 144 cells in all. Careful pencil-marking matters more, because a single missed elimination is easy to make and slow to find. Treat it as a longer, more meditative solve than the 9×9.
Numbers past nine
Because the digits run to 12, each cell can be two characters wide (10, 11, 12). Some puzzles instead use letters or hexadecimal-style symbols to keep every cell a single character, but the logic is unchanged - the symbols are just labels for twelve distinct values.
Solving strategy
- Pencil-mark methodically. With twelve possible values per cell, candidate notes are essential.
- Work box by box. Finish scanning one 3×4 box before moving on, so you don't lose your place.
- Hunt hidden singles per value. Take one value at a time and place it wherever it is confined to a single cell.
- Use the same techniques as 9×9. Naked pairs, hidden singles and X-Wings all scale up unchanged.
Common mistakes
- Expecting square boxes. The boxes are 3×4 rectangles - check the borders before reasoning about a box.
- Forgetting a value. All twelve must appear - it is easy to overlook 10, 11 or 12 while scanning.
- Sloppy candidate marks. On a grid this size, one wrong pencil mark can derail the whole solve.
- Rushing. The 12×12 rewards steady, careful work far more than speed.
Can I play it here?
Not yet - Sudoku 12×12 isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile:
- Try the closely related Classic, which you can play right now.
- Browse all the Sudoku variants we do offer.
- Or print free puzzles from the printable PDF page.
Where to play it
Sudoku 12×12 belongs to the size variant family and runs on 12×12. It is not one SudokuStreak generates yet - but the deduction it trains is the deduction every Sudoku runs on.
Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Expert Sudoku leaves 25 of the 81 cells filled, where the beginner tools dry up almost entirely; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.