Sudoku Solution No. 119

Hard Score 72 / 100
Digits appear one by one.

Step-by-step solution

Steps 64 Estimated time 104 – 156 min Hardest technique X-Wing Clues 23
Given digit (clue) Solved digit Placement (✓ RlCc=d) Elimination (✗ RlCc≠d)
1 Hidden Single ✓ R4C7=8
Scan the empty cells in this box where 8 could go. Across the whole box, 8 has only one possible spot left. So R4C7 = 8.
2 Hidden Single ✓ R5C8=2
Scan the empty cells in this box where 2 could go. Across the whole box, 2 has only one possible spot left. So R5C8 = 2.
3 Hidden Single ✓ R7C9=5
Scan the empty cells in this box where 5 could go. Across the whole box, 5 has only one possible spot left. So R7C9 = 5.
4 Hidden Single ✓ R8C9=8
Scan the empty cells in this box where 8 could go. Across the whole box, 8 has only one possible spot left. So R8C9 = 8.
5 Hidden Single ✓ R9C7=2
Scan the empty cells in this column where 2 could go. Across the whole column, 2 has only one possible spot left. So R9C7 = 2.
6 Naked Single ✓ R9C2=3
Look at cell R9C2. Every other digit already appears in its row, column or box. Only one option remains: R9C2 = 3.
7 Hidden Single ✓ R3C9=1
Scan the empty cells in this column where 1 could go. Across the whole column, 1 has only one possible spot left. So R3C9 = 1.
8 Hidden Single ✓ R6C2=2
Scan the empty cells in this column where 2 could go. Across the whole column, 2 has only one possible spot left. So R6C2 = 2.
9 Naked Pair ✗ 3 eliminations
Spot R2C7 and R3C7 in this box. These two cells can only hold 5 and 9: they reserve those digits. 5 and 9 are therefore removed from the other cells of the box.
10 Naked Single ✓ R1C9=6
Look at cell R1C9. Every other digit already appears in its row, column or box. Only one option remains: R1C9 = 6.
11 Naked Single ✓ R5C9=3
Look at cell R5C9. Every other digit already appears in its row, column or box. Only one option remains: R5C9 = 3.
12 Naked Single ✓ R4C9=9
Look at cell R4C9. Every other digit already appears in its row, column or box. Only one option remains: R4C9 = 9.
13 Naked Single ✓ R4C8=6
Look at cell R4C8. Every other digit already appears in its row, column or box. Only one option remains: R4C8 = 6.
14 Naked Single ✓ R4C2=1
Look at cell R4C2. Every other digit already appears in its row, column or box. Only one option remains: R4C2 = 1.
15 Naked Single ✓ R2C2=6
Look at cell R2C2. Every other digit already appears in its row, column or box. Only one option remains: R2C2 = 6.
16 Hidden Single ✓ R1C1=2
Scan the empty cells in this box where 2 could go. Across the whole box, 2 has only one possible spot left. So R1C1 = 2.
17 Hidden Single ✓ R1C3=8
Scan the empty cells in this box where 8 could go. Across the whole box, 8 has only one possible spot left. So R1C3 = 8.
18 Hidden Single ✓ R2C1=1
Scan the empty cells in this row where 1 could go. Across the whole row, 1 has only one possible spot left. So R2C1 = 1.
19 Hidden Single ✓ R6C3=6
Scan the empty cells in this column where 6 could go. Across the whole column, 6 has only one possible spot left. So R6C3 = 6.
20 Hidden Single ✓ R7C5=2
Scan the empty cells in this box where 2 could go. Across the whole box, 2 has only one possible spot left. So R7C5 = 2.
21 Hidden Single ✓ R8C3=2
Scan the empty cells in this box where 2 could go. Across the whole box, 2 has only one possible spot left. So R8C3 = 2.
22 Hidden Single ✓ R1C6=9
Scan the empty cells in this row where 9 could go. Across the whole row, 9 has only one possible spot left. So R1C6 = 9.
23 Hidden Single ✓ R6C5=9
Scan the empty cells in this box where 9 could go. Across the whole box, 9 has only one possible spot left. So R6C5 = 9.
24 Hidden Pair ✗ 5 eliminations
Find where 1 and 6 can go on this column. These two digits only fit in R5C4 and R9C4 on the column. The other candidates in R5C4 and R9C4 are therefore eliminated.
25 Hidden Single ✓ R5C1=8
Scan the empty cells in this box where 8 could go. Across the whole box, 8 has only one possible spot left. So R5C1 = 8.
26 Hidden Single ✓ R6C4=8
Scan the empty cells in this column where 8 could go. Across the whole column, 8 has only one possible spot left. So R6C4 = 8.
27 Hidden Single ✓ R9C6=8
Scan the empty cells in this row where 8 could go. Across the whole row, 8 has only one possible spot left. So R9C6 = 8.
28 Pointing ✗ 3 eliminations
(1) Look at where 5 can go in this box. (2) Look at where 5 can go in this box. (1) All its spots lie on a single row (R4C1 and R4C3). (2) All its spots lie on a single row (R9C1 and R9C3). (1) 5 is therefore removed from that row outside the box. (2) 5 is therefore removed from that row outside the box.
29 Hidden Single ✓ R2C4=5
Scan the empty cells in this column where 5 could go. Across the whole column, 5 has only one possible spot left. So R2C4 = 5.
30 Hidden Single ✓ R2C7=9
Scan the empty cells in this box where 9 could go. Across the whole box, 9 has only one possible spot left. So R2C7 = 9.
31 Hidden Single ✓ R3C7=5
Scan the empty cells in this box where 5 could go. Across the whole box, 5 has only one possible spot left. So R3C7 = 5.
32 Hidden Pair ✗ 2 eliminations
Find where 1 and 5 can go on this column. These two digits only fit in R5C6 and R8C6 on the column. The other candidates in R5C6 and R8C6 are therefore eliminated.
33 Hidden Single ✓ R3C6=6
Scan the empty cells in this column where 6 could go. Across the whole column, 6 has only one possible spot left. So R3C6 = 6.
34 Skyscraper ✗ 2 eliminations
Find 3 on two rows, each with exactly two candidate positions. A shared column connects one end of each pair. Whichever way the logic falls, one of the two free ends must hold 3. R3C1 and R4C3 is seen by both free ends: 3 is therefore eliminated there.
35 Two-String Kite ✗ 1 elimination
Find 7 on one row and one column, each with two candidate positions, sharing a box. The two strands meet in the shared box. One of the two free ends must hold 7. R3C1 is seen by both free ends: 7 is therefore eliminated there.
36 Naked Single ✓ R3C1=9
Look at cell R3C1. Every other digit already appears in its row, column or box. Only one option remains: R3C1 = 9.
37 Naked Single ✓ R7C1=4
Look at cell R7C1. Every other digit already appears in its row, column or box. Only one option remains: R7C1 = 4.
38 Naked Single ✓ R9C1=5
Look at cell R9C1. Every other digit already appears in its row, column or box. Only one option remains: R9C1 = 5.
39 Naked Single ✓ R9C3=9
Look at cell R9C3. Every other digit already appears in its row, column or box. Only one option remains: R9C3 = 9.
40 Naked Single ✓ R9C8=1
Look at cell R9C8. Every other digit already appears in its row, column or box. Only one option remains: R9C8 = 1.
41 Naked Single ✓ R8C8=3
Look at cell R8C8. Every other digit already appears in its row, column or box. Only one option remains: R8C8 = 3.
42 Naked Single ✓ R9C4=6
Look at cell R9C4. Every other digit already appears in its row, column or box. Only one option remains: R9C4 = 6.
43 Naked Single ✓ R9C5=4
Look at cell R9C5. Every other digit already appears in its row, column or box. Only one option remains: R9C5 = 4.
44 Naked Single ✓ R5C4=1
Look at cell R5C4. Every other digit already appears in its row, column or box. Only one option remains: R5C4 = 1.
45 Naked Single ✓ R5C6=5
Look at cell R5C6. Every other digit already appears in its row, column or box. Only one option remains: R5C6 = 5.
46 Naked Single ✓ R7C8=9
Look at cell R7C8. Every other digit already appears in its row, column or box. Only one option remains: R7C8 = 9.
47 Naked Single ✓ R8C5=5
Look at cell R8C5. Every other digit already appears in its row, column or box. Only one option remains: R8C5 = 5.
48 Naked Single ✓ R8C6=1
Look at cell R8C6. Every other digit already appears in its row, column or box. Only one option remains: R8C6 = 1.
49 Naked Single ✓ R5C5=6
Look at cell R5C5. Every other digit already appears in its row, column or box. Only one option remains: R5C5 = 6.
50 Hidden Single ✓ R1C4=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R1C4 = 7.
51 Hidden Single ✓ R1C8=4
Scan the empty cells in this box where 4 could go. Across the whole box, 4 has only one possible spot left. So R1C8 = 4.
52 Hidden Single ✓ R2C6=4
Scan the empty cells in this column where 4 could go. Across the whole column, 4 has only one possible spot left. So R2C6 = 4.
53 Hidden Single ✓ R2C8=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R2C8 = 7.
54 Hidden Single ✓ R3C3=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R3C3 = 7.
55 Hidden Single ✓ R3C5=3
Scan the empty cells in this box where 3 could go. Across the whole box, 3 has only one possible spot left. So R3C5 = 3.
56 Hidden Single ✓ R4C3=5
Scan the empty cells in this row where 5 could go. Across the whole row, 5 has only one possible spot left. So R4C3 = 5.
57 Hidden Single ✓ R4C4=4
Scan the empty cells in this row where 4 could go. Across the whole row, 4 has only one possible spot left. So R4C4 = 4.
58 Hidden Single ✓ R4C5=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R4C5 = 7.
59 Hidden Single ✓ R6C1=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R6C1 = 7.
60 Hidden Single ✓ R6C6=3
Scan the empty cells in this box where 3 could go. Across the whole box, 3 has only one possible spot left. So R6C6 = 3.
61 Hidden Single ✓ R7C4=3
Scan the empty cells in this box where 3 could go. Across the whole box, 3 has only one possible spot left. So R7C4 = 3.
62 Hidden Single ✓ R7C6=7
Scan the empty cells in this box where 7 could go. Across the whole box, 7 has only one possible spot left. So R7C6 = 7.
63 Naked Single ✓ R2C3=3
Look at cell R2C3. Every other digit already appears in its row, column or box. Only one option remains: R2C3 = 3.
64 Naked Single ✓ R4C1=3
Look at cell R4C1. Every other digit already appears in its row, column or box. Only one option remains: R4C1 = 3.