Evil Odd Even Sudoku Puzzles

About Odd-Even Sudoku

Odd Even Sudoku is a special type of Sudoku puzzle with extra rules. Some cells are marked to show if they must have odd numbers (like 1, 3, 5, 7, 9) or even numbers (like 2, 4, 6, 8). This adds an extra challenge and makes solving the puzzle more interesting.

Rules / How to Play

• Grid Size: he grid is typically 9x9, divided into 9 smaller 3x3 sub grids.
• Unique Numbers: Each row, column, and 3x3 sub-grid must contain the digits 1 through 9 without repetition.
• Odd/Even Constraint: Cells marked with a symbol (e.g., a circle or a square) must contain a digit of the specified parity (odd or even).
• Unmarked Cells: Cells without any parity designation can contain any digit from 1 to 9, following the standard Sudoku rules.

Solving Tips and Techniques:

• Parity Elimination: If a cell is designated as "odd," you can eliminate all even digits from its possibilities. Similarly, if a cell is designated as "even," you can eliminate all odd digits.
• Start with Obvious Numbers: Check the rows, columns, or sub-grids to see if certain numbers are limited because of the "Even" or "Odd" markings. For example, if a sub-grid already has four even numbers filled in and a cell is marked as "Even," the rest of the numbers in that subgrid must all be odd.
• Use Cross-Hatching: Like in regular Sudoku, you can use cross-hatching (looking at how rows and columns overlap) to figure out where numbers go. This is especially helpful for cells marked with odd or even numbers.
• Candidate Elimination: Use the parity rules to reduce the possible numbers for each cell. For example, if a cell is in a row and subgrid where many odd numbers are already filled in, the remaining choices for that cell might only be even numbers.
• Odd and Even Numbers Distribution: Each 3x3 grid in the puzzle must have exactly 5 odd numbers and 4 even numbers, or 5 even numbers and 4 odd numbers. Keeping track of this balance can help you make decisions, especially as you get closer to finishing the puzzle.

Odd Even Sudoku adds a fun twist to the regular Sudoku game. It mixes the usual logic with a new rule about numbers being odd or even. By understanding this new rule, players can solve harder puzzles more easily.