Classic Sudoku · 41
Classic Sudoku · 41: a 9×9 Sudoku with 36 clues and one solution. Play online, use pencil notes and hints, or compare the complete answer.
Use rows and columns: R1C1 is row 1, column 1. Enter digits inside the squares.
Read the position, one decision at a time
Follow the deductions in order. Each step uses the grid after the preceding entry.
Reveal step-by-step explanations
Deduction 1: R7C3 = 2
After the preceding deductions, row 7, column 3 has only candidate 2. Its row, column and box exclude every other digit. Enter 2, then update the remaining candidates; this conclusion does not require consulting the completed answer.
Check the existing digits: row 7: 1; column 3: 1, 4, 5, 6, 7, 8, 9; box: 1, 3, 6, 9. Each digit already present rules out that candidate in this cell.
Deduction 2: R5C3 = 3
After the preceding deductions, row 5, column 3 has only candidate 3. Its row, column and box exclude every other digit. Enter 3, then update the remaining candidates; this conclusion does not require consulting the completed answer.
Check the existing digits: row 5: 4, 5, 6, 9; column 3: 1, 2, 4, 5, 6, 7, 8, 9; box: 5, 6, 7, 9. Each digit already present rules out that candidate in this cell.
Deduction 3: R1C6 = 4
This cell has candidates 4, 7, but 4 occurs in only this cell of row 1. This is a hidden single, not a guess between its candidates.
Check the existing digits: row 1: 1, 8; column 6: 1, 2, 5, 9; box: 1, 2, 3, 5, 6. Each digit already present rules out that candidate in this cell.
Deduction 4: R1C8 = 5
This cell has candidates 2, 3, 5, 6, 7, but 5 occurs in only this cell of row 1. This is a hidden single, not a guess between its candidates.
Check the existing digits: row 1: 1, 4, 8; column 8: 1, 4, 9; box: 1, 4, 9. Each digit already present rules out that candidate in this cell.
Understand this position
9×9 grid · 3×3 boxes · 36 clues · 45 empty cells
Start by inspecting row 7, column 3. From the starting grid, its legal candidates are 2. Check the filled digits in that row, column and box before entering a number. Only one candidate remains: this is a naked single.
Read the complete answer by row
7 · 2 · 8 · 9 · 1 · 4 · 3 · 5 · 63 · 6 · 5 · 7 · 2 · 8 · 9 · 4 · 19 · 1 · 4 · 3 · 6 · 5 · 7 · 8 · 26 · 5 · 9 · 2 · 8 · 3 · 1 · 7 · 42 · 8 · 3 · 1 · 4 · 7 · 6 · 9 · 51 · 4 · 7 · 6 · 5 · 9 · 2 · 3 · 84 · 7 · 2 · 5 · 9 · 1 · 8 · 6 · 35 · 9 · 1 · 8 · 3 · 6 · 4 · 2 · 78 · 3 · 6 · 4 · 7 · 2 · 5 · 1 · 9