Sudoku 10×10 – Hard

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Sudoku 10x10 is a variant of the classic Sudoku puzzle, but with a slightly larger grid and altered regions. The grid is made up of 10x10 squares instead of the traditional 9x9. The objective remains to fill in the grid in a way that adheres to certain rules, ensuring each number is used precisely once in each row, column, and region.

Basic Rules

1. Grid Structure: The puzzle consists of a 10x10 grid, which is further divided into 5x2 regions.
2. Pre-filled Numbers: Some cells in the grid are pre-filled with numbers; these are fixed and cannot be changed.
3. Number Range: Numbers 1 through 10 are used to fill the grid.

Additional Rules

• Unique Numbers: Each number (1-10) must appear exactly once in each row, column, and defined region.

Basic Solving Tips

1. Scan First: Always start by looking for rows, columns, or regions where most numbers are already filled in.
2. Single Possibility: If a square has only one possible number, fill it in.
3. Exclusion: Exclude impossible numbers in a square by checking its row, column, and region.
4. Double Pairs: Look for any rows, columns, or regions where only two numbers are missing, as these can often be solved quickly.
5. Avoid Guessing: Try to ensure that every number you fill in is definite and avoid random guesses.