Objective of the Game
The goal of Sudoku is to fill all the empty cells in a 9x9 grid with the digits 1 to 9 in such a way that each digit appears exactly once in each row, column, and each of the nine 3x3 subgrids (also known as "boxes").
Setup
A Sudoku puzzle consists of a 9x9 grid divided into nine 3x3 subgrids. At the beginning of the game, some of these cells are already filled with numbers from 1 to 9, while others are empty.
Rules
- Row Rule: Each number from 1 to 9 must appear exactly once in each row.
- Column Rule: Each number from 1 to 9 must appear exactly once in each column.
- Box Rule: Each number from 1 to 9 must appear exactly once in each of the nine 3x3 subgrids.
Gameplay
- Players fill in the empty cells with numbers. An entry is correct if it does not violate the above rules.
- There is no fixed order in which the numbers must be filled in, but the correctness of the entries is crucial.
- The game ends when all cells are correctly filled.
Strategies
- Visible Uniqueness: Look for numbers that are almost entirely filled in a row, column, or box; the missing number must then be placed in the only remaining empty cell.
- Exclusion: Check where numbers cannot go to determine where they must go.
- Pencil Marks: Mark possible numbers in empty cells to narrow down possibilities.
- Systematic Approach: Work systematically row by row, column by column, or box by box to find overlooked numbers.
Special Features
- Difficulty Level: Easy Sudokus have many prefixed numbers, while difficult ones have very few.
- Variants: There are variants like Killer Sudoku, where the sums of specific areas must be considered in addition to the basic rule.
Sudoku is a pure logic and combination game without any element of chance, and it can be solved alone or cooperatively in groups.
