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How to Play Sudoku: A Beginner's Guide

Sudoku is a logic-based number placement puzzle played on a 9x9 grid. This guide explains the rules, strategies, and tips to master Sudoku online.

Sudoku Game Objective

Fill the 9x9 grid with numbers from 1 to 9 so that each row, column, and 3x3 subgrid contains all digits from 1 to 9 exactly once, without repetition.

Sudoku Rules

• Grid Setup: The 9x9 grid is divided into nine 3x3 subgrids. Some cells start with numbers ("givens"), while others are empty.
• Number Placement: Place numbers 1 to 9 in empty cells.
• Constraints:
  • Each row must have all numbers 1 to 9 without repetition.
  • Each column must have all numbers 1 to 9 without repetition.
  • Each 3x3 subgrid must have all numbers 1 to 9 without repetition.
• Winning: Solve the puzzle by filling all cells correctly.

Basic Sudoku Strategies

• Start with Obvious Placements: Find cells with only one possible number based on givens.
• Elimination: Rule out numbers already present in a cell's row, column, or subgrid.
• Single Candidate: Place a number if it's the only one that fits a cell.
• Hidden Singles: Place a number if it's the only cell in a row, column, or subgrid that can hold it.

Advanced Tips

• Pencil Marks: Use our notes feature to track possible numbers for each cell.
• Naked Pairs/Triples: If two or three cells in a unit can only contain the same numbers, eliminate them from other cells in that unit.
• Locked Candidates: If a number in a subgrid can only appear in one row or column, eliminate it elsewhere in that row or column, and vice versa.

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