The 17 Clue Sudoku
Here is a 17 Clue Sudoku. We have solved this puzzle step-by-step by using two techniques; Naked Single and Hidden Single.
Solution to the 17 Clue Sudoku
To begin with, we need to right down all the candidate numbers for all the empty cells.
Step 1: Naked Single in cell ( G5 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7, and candidate 7 removed from cells (G2, G3, G6, G8, A5, B5, C5, E5, H5, I5, H6).
Step 2: Hidden Single in cell ( D6 )
The cell is the only cell in row D with the candidate value 1. Hence this cell is solved with the value 1, and candidate 1 removed from cells (B6, C6, E6, E5).
Step 3: Hidden Single in cell ( D8 )
The cell is the only cell in row D with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (B8, C8, F8, G8, H8, F7, F9).
Step 4: Hidden Single in cell ( E9 )
The cell is the only cell in row E with the candidate value 1. Hence this cell is solved with the value 1, and candidate 1 removed from cells (G9, I9).
Step 5: Hidden Single in cell ( F6 )
The cell is the only cell in row F with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (A6, B6, C6).
Step 6: Hidden Single in cell ( F2 )
The cell is the only cell in row F with the candidate value 4. Hence this cell is solved with the value 4, and candidate 4 removed from cells (E2, I2).
Step 7: Hidden Single in cell ( F4 )
The cell is the only cell in row F with the candidate value 3. Hence this cell is solved with the value 3, and candidate 3 removed from cells (A4, B4, C4, D4).
Step 8: Hidden Single in cell ( F1 )
The cell is the only cell in row F with the candidate value 7. Hence this cell is solved with the value 7, and candidate 7 removed from cells (A1, C1, E1, H1, I1, E2).
Step 9: Hidden Single in cell ( G2 )
The cell is the only cell in row G with the candidate value 1. Hence this cell is solved with the value 1, and candidate 1 removed from cells (B2, I2, I1).
Step 10: Hidden Single in cell ( B5 )
The cell is the only cell in row B with the candidate value 1. Hence this cell is solved with the value 1, and candidate 1 removed from cells (C5).
Step 11: Hidden Single in cell ( C1 )
The cell is the only cell in row C with the candidate value 1. Hence this cell is solved with the value 1.
Step 12: Hidden Single in cell ( G9 )
The cell is the only cell in row G with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (A9, B9, C9, H9, H7).
Step 13: Hidden Single in cell ( H1 )
The cell is the only cell in row H with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (A1).
Step 14: Hidden Single in cell ( I7 )
The cell is the only cell in row I with the candidate value 1. Hence this cell is solved with the value 1.
Step 15: Hidden Single in cell ( E1 )
The cell is the only cell in box 4 with the candidate value 5. Hence this cell is solved with the value 5, and candidate 5 removed from cells (E8, A1).
Step 16: Hidden Single in cell ( E8 )
The cell is the only cell in box 6 with the candidate value 9. Hence this cell is solved with the value 9, and candidate 9 removed from cells (E2, B8, C8, G8, H8, I8).
Step 17: Naked Single in cell ( E2 )
The cell has a single candidate with the value 6. Hence this cell is solved with the value 6, and candidate 6 removed from cells (E4, E5, A2, B2, D2, D1, D3).
Step 18: Hidden Single in cell ( D4 )
The cell is the only cell in row D with the candidate value 6. Hence this cell is solved with the value 6, and candidate 6 removed from cells (A4, B4, C4).
Step 19: Hidden Single in cell ( A1 )
The cell is the only cell in column 1 with the candidate value 6. Hence this cell is solved with the value 6, and candidate 6 removed from cells (A3, A5, A7, A9, B3, C3).
Step 20: Hidden Single in cell ( C5 )
The cell is the only cell in column 5 with the candidate value 6. Hence this cell is solved with the value 6, and candidate 6 removed from cells (C7, C8, C9).
Step 21: Hidden Single in cell ( C7 )
The cell is the only cell in row C with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (A7, B7).
Step 22: Hidden Single in cell ( B2 )
The cell is the only cell in row B with the candidate value 8. Hence this cell is solved with the value 8, and candidate 8 removed from cells (A2).
Step 23: Hidden Single in cell ( A5 )
The cell is the only cell in row A with the candidate value 8. Hence this cell is solved with the value 8.
Step 24: Hidden Single in cell ( E5 )
The cell is the only cell in column 5 with the candidate value 4. Hence this cell is solved with the value 4, and candidate 4 removed from cells (E6).
Step 25: Hidden Single in cell ( G6 )
The cell is the only cell in box 8 with the candidate value 5. Hence this cell is solved with the value 5, and candidate 5 is removed from cells (G8, A6, B6, C6).
Step 26: Naked Single in cell ( G8 )
The cell has a single candidate with the value 6. Hence this cell is solved with the value 6, and candidate 6 is removed from cells (G3, B8, F8, H8, H7, H9).
Step 27: Naked Single in cell ( G3 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (A3, B3, C3, D3, H3, I3, I1, I2).
Step 28: Naked Single in cell ( I2 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7, and candidate 7 is removed from cells (I3, I8, A2, H3).
Step 29: Naked Single in cell ( I1 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2, and candidate 2 is removed from cells (I3, I5, D1, H3).
Step 30: Naked Single in cell ( D1 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (D2).
Step 31: Naked Single in cell ( I3 )
The cell has a single candidate with the value 4. Hence this cell is solved with the value 4, and candidate 4 is removed from cells (I8, I9, H3).
Step 32: Naked Single in cell ( I5 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3, and candidate 3 is removed from cells (I8, I9, H5, H6).
Step 33: Naked Single in cell ( D2 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3, and candidate 3 is removed from cells (D3, A2).
Step 34: Naked Single in cell ( H3 )
The cell has a single candidate with the value 6. Hence this cell is solved with the value 6.
Step 35: Naked Single in cell ( H5 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2, and candidate 2 is removed from cells (H6).
Step 36: Naked Single in cell ( I8 )
The cell has a single candidate with the value 5. Hence this cell is solved with the value 5, and candidate 5 is removed from cells (I9, B8, C8, F8).
Step 37: Naked Single in cell ( A2 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (A4, A6, A7, A9).
Step 38: Naked Single in cell ( D3 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2.
Step 39: Naked Single in cell ( F8 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2, and candidate 2 is removed from cells (F9, B8).
Step 40: Naked Single in cell ( H6 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (H7, H9, B6, C6).
Step 41: Naked Single in cell ( I9 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (B9, C9).
Step 42: Naked Single in cell ( H7 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7, and candidate 7 is removed from cells (H8, A7, B7).
Step 43: Naked Single in cell ( A7 )
The cell has a single candidate with the value 5. Hence this cell is solved with the value 5, and candidate 5 is removed from cells (A3, A4, A9, B7, F7, B9, C9).
Step 44: Naked Single in cell ( F7 )
The cell has a single candidate with the value 6. Hence this cell is solved with the value 6, and candidate 6 is removed from cells (F9, B7).
Step 45: Naked Single in cell ( B7 )
The cell has a single candidate with the value 9. Hence this cell is solved with the value 9, and candidate 9 is removed from cells (B4).
Step 46: Naked Single in cell ( F9 )
The cell has a single candidate with the value 5. Hence this cell is solved with the value 5.
Step 47: Hidden Single in cell ( B9 )
The cell is the only cell in row B with the candidate value 6. Hence this cell is solved with the value 6.
Step 48: Hidden Single in cell ( C4 )
The cell is the only cell in row C with the candidate value 9. Hence this cell is solved with the value 9.
Step 49: Hidden Single in cell ( C3 )
The cell is the only cell in row C with the candidate value 5. Hence this cell is solved with the value 5, and candidate 5 is removed from cells (B3).
Step 50: Hidden Single in cell ( B4 )
The cell is the only cell in row B with the candidate value 5. Hence this cell is solved with the value 5.
Step 51: Hidden Single in cell ( B6 )
The cell is the only cell in row B with the candidate value 2. Hence this cell is solved with the value 2, and candidate is 2 removed from cells (A6, E6, A4).
Step 52: Naked Single in cell ( A4 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7, and candidate 7 is removed from cells (A3, A6, E4, C6).
Step 53: Naked Single in cell ( E6 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7.
Step 54: Naked Single in cell ( A3 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3, and candidate 3 is removed from cells (A6, A9, B3).
Step 55: Naked Single in cell ( E4 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2.
Step 56: Naked Single in cell ( A6 )
The cell has a single candidate with the value 4. Hence this cell is solved with the value 4, and candidate 4 is removed from cells (A9, C6).
Step 57: Naked Single in cell ( B3 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7, and candidate 7 is removed from cells (B8).
Step 58: Naked Single in cell ( A9 )
The cell has a single candidate with the value 2. Hence this cell is solved with the value 2.
Step 59: Naked Single in cell ( B8 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3, and candidate 3 is removed from cells (C8, H8, C9).
Step 60: Naked Single in cell ( C6 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3.
Step 61: Naked Single in cell ( C9 )
The cell has a single candidate with the value 4. Hence this cell is solved with the value 4, and candidate 4 is removed from cells (C8, H9).
Step 62: Naked Single in cell ( H8 )
The cell has a single candidate with the value 4. Hence this cell is solved with the value 4.
Step 63: Naked Single in cell ( C8 )
The cell has a single candidate with the value 7. Hence this cell is solved with the value 7.
Step 64: Naked Single in cell ( H9 )
The cell has a single candidate with the value 3. Hence this cell is solved with the value 3.
