Easy Odd/Even Sudoku

Shaded cells must hold odd digits; unshaded cells hold even digits. Parity clues cut candidates in half and make every placement count. Free online.

Easy Medium Hard Expert

New to Odd/Even Sudoku? Purple-ringed cells must hold odd digits (1,3,5,7,9) and yellow cells must hold even digits (2,4,6,8). Start here.

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4
8
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2
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9
8
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6
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1
9
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7
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9
5
3
Mistakes
0/3
Score
-
Time
00:00
Try Medium Odd-Even Sudoku →
Progress0%
Odd Even

What is Odd / Even Sudoku?

Difficulty
★★★☆☆
3/5
Constraint Type
Cell Relationships
Typical Givens
20–26
Avg. Solve (Easy)
6 min

Solving Techniques for Easy Level

Technique Description Level
Immediate Candidate Halving Marked cells instantly reduce to 5 odd candidates (1,3,5,7,9) or 4 even candidates (2,4,6,8). Apply this before any other technique. Beginner

Ready to go deeper? Try Medium Odd / Even Sudoku to unlock Intermediate techniques.

Techniques to Master at Easy

  • Last Possible Number technique — Shaded cells start at four or five candidates instead of nine — parity does half the elimination before you even cross-check row, column, and box.
  • Last Remaining Cell technique — An odd digit hunting for a home can skip every even-shaded cell in the unit, so the "only place left" moment arrives much sooner than in classic Sudoku.

Average Solve Time by Difficulty

Easy
6 min
Medium
14 min
Hard
28 min
Expert
50 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Odd / Even Sudoku →

Related Variants

Greater Than Sudoku

Builds on value reasoning — inequality chains bound cells from both ends much like parity halves them.

Kropki Sudoku

Moves from cell properties to cell relationships: dots encode consecutive and doubled neighbours.

Consecutive Sudoku

Neighbour-difference logic with a strong negative constraint — a natural next step from parity counting.

Frequently Asked Questions — Easy Odd/Even Sudoku

What is Odd/Even Sudoku?
Odd/Even Sudoku is a Sudoku variant where some cells are shaded to indicate their parity. Purple-ringed cells must contain an odd digit (1, 3, 5, 7, or 9). Yellow cells must contain an even digit (2, 4, 6, or 8). All standard Sudoku rules for rows, columns, and 3×3 boxes still apply.
Which digits are odd and which are even in Odd/Even Sudoku?
Odd digits are 1, 3, 5, 7, and 9. Even digits are 2, 4, 6, and 8. Notice there are five odd digits and only four even digits in the range 1–9. This asymmetry matters when a row or column has many parity-marked cells — it constrains which digits can go where.
How do I use the parity clues to solve the puzzle?
When you see a purple-ringed (odd) cell, immediately remove 2, 4, 6, and 8 from its candidates. When you see a yellow (even) cell, remove 1, 3, 5, 7, and 9. Apply this reduction to every shaded cell before you start scanning rows and columns. The parity constraints dramatically narrow down candidates from the first move.
How do I start an easy Odd/Even Sudoku?
First, apply parity restrictions to all shaded cells. Then scan rows, columns, and boxes for digits that appear many times — with parity already cutting many candidates, naked singles are easy to spot. Easy puzzles have enough parity markings that basic scanning and parity elimination are all you need.
What happens if I put an even digit in an odd cell?
The game counts it as a mistake. Odd cells (purple ring) must contain one of 1, 3, 5, 7, or 9 — placing 2, 4, 6, or 8 violates the parity constraint. Make sure to apply parity elimination before entering any digit to avoid accidental mistakes.

More questions? See the full Odd/Even Sudoku guide.