Mini Sudoku · 49
Mini Sudoku · 49: a 4×4 Sudoku with 7 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: R2C1 = 3
After the preceding deductions, row 2, column 1 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 2: 4; column 1: 1, 2; box: 2, 4. Each digit already present rules out that candidate in this cell.
Deduction 2: R1C2 = 1
After the preceding deductions, row 1, column 2 has only candidate 1. Its row, column and box exclude every other digit. Enter 1, then update the remaining candidates; this conclusion does not require consulting the completed answer.
Check the existing digits: row 1: 2, 4; column 2: 4; box: 2, 3, 4. Each digit already present rules out that candidate in this cell.
Deduction 3: R1C3 = 3
After the preceding deductions, row 1, 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 1: 1, 2, 4; column 3: 4; box: 4. Each digit already present rules out that candidate in this cell.
Deduction 4: R2C4 = 1
After the preceding deductions, row 2, column 4 has only candidate 1. Its row, column and box exclude every other digit. Enter 1, then update the remaining candidates; this conclusion does not require consulting the completed answer.
Check the existing digits: row 2: 3, 4; column 4: 2, 3, 4; box: 3, 4. Each digit already present rules out that candidate in this cell.
Understand this position
4×4 grid · 2×2 boxes · 7 clues · 9 empty cells
Start by inspecting row 2, column 1. From the starting grid, its legal candidates are 3. 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
2 · 1 · 3 · 43 · 4 · 2 · 14 · 2 · 1 · 31 · 3 · 4 · 2