Autosave — Your current game is saved in your browser after every move. If you leave the page, you'll be able to resume exactly where you left off. Saves are kept for 7 days.
Settings ⚙️ — For advanced players, the gear at the top of the page turns on the ✏️ Auto button: it fills in every candidate of the grid at once, or only the cleaned candidates (locked candidates removed). This second option counts as a hint: the game won’t count towards “No hints”. You’ll also find large print there, for easier reading.
Even-Odd Sudoku stats — They are kept separate from your classic 9×9 sudoku stats and the other variants. They're stored locally in your browser and never sent to a server.
Even-Odd Sudoku: shaded cells and white cells
Even-Odd Sudoku takes the classic 9×9 grid and adds a hint to every cell: shaded, it expects an even number (2, 4, 6 or 8); white, an odd number (1, 3, 5, 7 or 9). All the classic sudoku rules still apply.
That hint changes the way you play. A white cell never has more than five candidates, a shaded cell never more than four. The puzzles therefore start with fewer givens than a classic sudoku: the colour of the cells does part of the work.
Sudoku-Land offers 3 levels (easy, medium, hard), notes mode, a step-by-step solver for hints, autosave, a dark theme and the ⚙️ Settings menu. Every puzzle has a single solution and cannot be solved without the shaded cells: each one has been checked individually.
Even-Odd Sudoku rules
- Just like classic sudoku — every row, every column and every 3×3 box contains the numbers 1 to 9, once each.
- Shaded cell = even number — it takes a 2, a 4, a 6 or an 8.
- White cell = odd number — it takes a 1, a 3, a 5, a 7 or a 9.
Tips for solving an Even-Odd Sudoku
- Count the shaded cells — every row, every column and every box has exactly four, one per even number. When three even numbers are placed in a row, the last shaded cell takes the fourth.
- Split the two families — in a row, the even numbers only compete for the shaded cells, and the odd ones only for the white cells. Each group splits into two smaller, easier puzzles.
- Look for the cell that is left — if an odd number can only go in one white cell of a box, that is the one, even while shaded cells are still empty.
- Let your notes do the sorting — with the ✏️ Auto button in the ⚙️ menu, the notes only offer numbers of the right parity.
All the grids on Sudoku-Land
Frequently asked questions
What is Even-Odd Sudoku?
It is a 9×9 sudoku where every cell shows the parity of its number: a shaded cell takes an even number (2, 4, 6 or 8), a white cell an odd number (1, 3, 5, 7 or 9). The classic sudoku rules stay the same.
Why does the puzzle start with so few numbers?
Because the shaded and white cells already tell you a lot. Every row, every column and every box has exactly four shaded cells, for the four even numbers, and five white cells, for the five odd ones. So fewer givens are needed for the puzzle to have a single solution.
Is Even-Odd Sudoku harder than classic sudoku?
Rather the opposite, at the same level: a white cell never has more than five candidates, a shaded cell never more than four. The challenge comes mostly from the small number of givens. Sudoku-Land levels are graded with the same techniques as classic sudoku.
Does the Hint button work like in classic sudoku?
Yes: the Hint button opens a step-by-step solver that takes the shaded cells into account. It explains each deduction on a small grid where the even cells are shaded, and says when a cell is ruled out by its colour. Reading the steps is free; only “Apply this move” uses up a hint.