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Lesson 1: Understanding the Grid
⏱ 5 minLearn the 9×9 grid structure, rows, columns, and 3×3 boxes. Understand the terminology every Sudoku solver uses.
Grid anatomyRows, columns, boxesCell coordinates
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Beginner Level
Master the fundamentals of Sudoku. No prior knowledge needed — just curiosity and a bit of patience.
Lessons 1–5⏱ ~45 min total🆓 Free
Lesson List
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Lesson 2: The Core Rules
⏱ 5 minWhat makes a valid Sudoku solution? Master the three constraints that every digit must satisfy.
No duplicates per rowNo duplicates per columnNo duplicates per 3×3 box
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Lesson 3: Scanning Technique
⏱ 10 minUse cross-hatching to scan rows and columns, eliminating where a digit cannot go to reveal where it must go.
Cross-hatchingRow eliminationColumn elimination
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Lesson 4: Single Candidate Cells
⏱ 10 minFind cells where only one digit is possible by eliminating all others from the row, column, and box.
Naked SinglesCandidate countingForced placements
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Lesson 5: Your First Complete Solve
⏱ 15 minA step-by-step guided walkthrough solving an Easy puzzle from start to finish using everything you've learned.
Apply scanningUse singlesFull puzzle solve
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