Step-by-step solution
Steps 66
Estimated time 108 – 162 min
Hardest technique X-Wing
Clues 23
Given digit (clue)
Solved digit
Placement (✓ RlCc=d)
Elimination (✗ RlCc≠d)
Scan the empty cells in this column where 3 could go.
Across the whole column, 3 has only one possible spot left.
So R4C3 = 3.
Scan the empty cells in this column where 4 could go.
Across the whole column, 4 has only one possible spot left.
So R5C8 = 4.
Scan the empty cells in this row where 3 could go.
Across the whole row, 3 has only one possible spot left.
So R6C4 = 3.
Scan the empty cells in this box where 1 could go.
Across the whole box, 1 has only one possible spot left.
So R6C6 = 1.
Scan the empty cells in this row where 8 could go.
Across the whole row, 8 has only one possible spot left.
So R7C2 = 8.
Scan the empty cells in this column where 6 could go.
Across the whole column, 6 has only one possible spot left.
So R7C7 = 6.
Scan the empty cells in this row where 9 could go.
Across the whole row, 9 has only one possible spot left.
So R8C8 = 9.
Scan the empty cells in this box where 2 could go.
Across the whole box, 2 has only one possible spot left.
So R9C8 = 2.
Scan the empty cells in this box where 1 could go.
Across the whole box, 1 has only one possible spot left.
So R9C9 = 1.
Scan the empty cells in this box where 4 could go.
Across the whole box, 4 has only one possible spot left.
So R1C4 = 4.
Scan the empty cells in this box where 9 could go.
Across the whole box, 9 has only one possible spot left.
So R2C4 = 9.
Scan the empty cells in this box where 9 could go.
Across the whole box, 9 has only one possible spot left.
So R4C2 = 9.
Scan the empty cells in this box where 5 could go.
Across the whole box, 5 has only one possible spot left.
So R4C6 = 5.
Scan the empty cells in this row where 2 could go.
Across the whole row, 2 has only one possible spot left.
So R6C2 = 2.
Scan the empty cells in this box where 9 could go.
Across the whole box, 9 has only one possible spot left.
So R6C7 = 9.
Scan the empty cells in this box where 5 could go.
Across the whole box, 5 has only one possible spot left.
So R7C5 = 5.
Scan the empty cells in this row where 4 could go.
Across the whole row, 4 has only one possible spot left.
So R7C6 = 4.
Scan the empty cells in this row where 1 could go.
Across the whole row, 1 has only one possible spot left.
So R2C5 = 1.
Scan the empty cells in this row where 4 could go.
Across the whole row, 4 has only one possible spot left.
So R4C1 = 4.
Scan the empty cells in this column where 1 could go.
Across the whole column, 1 has only one possible spot left.
So R8C4 = 1.
(1) Find where 2 and 9 can go on this column. (2) Find where 2 and 9 can go in this box. (3) Find where 3 and 8 can go in this box.
(1) These two digits only fit in R1C3 and R3C3 on the column. (2) These two digits only fit in R1C3 and R3C3 in the box. (3) These two digits only fit in R1C5 and R3C5 in the box.
(1) The other candidates in R1C3 and R3C3 are therefore eliminated. (2) The other candidates in R1C3 and R3C3 are therefore eliminated. (3) The other candidates in R1C5 and R3C5 are therefore eliminated.
Scan the empty cells in this box where 1 could go.
Across the whole box, 1 has only one possible spot left.
So R1C2 = 1.
Scan the empty cells in this row where 4 could go.
Across the whole row, 4 has only one possible spot left.
So R3C2 = 4.
Scan the empty cells in this box where 1 could go.
Across the whole box, 1 has only one possible spot left.
So R3C7 = 1.
Scan the empty cells in this column where 4 could go.
Across the whole column, 4 has only one possible spot left.
So R9C3 = 4.
Spot R1C5 and R3C5 on this column.
These two cells can only hold 3 and 8: they reserve those digits.
3 and 8 are therefore removed from the other cells of the column.
Look at where 6 can go in this box.
All its spots lie on a single row (R5C2 and R5C3).
6 is therefore removed from that row outside the box.
Look at where 6 can go on this column.
All its spots lie within a single box (R1C1 and R2C1).
6 is therefore removed from the rest of the box.
Find 5 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 5.
R1C1 is seen by both free ends: 5 is therefore eliminated there.
Look at where 5 can go in this box.
All its spots lie on a single row (R2C1 and R2C3).
5 is therefore removed from that row outside the box.
Spot R1C7 and R2C8 in this box.
These two cells can only hold 7 and 8: they reserve those digits.
7 and 8 are therefore removed from the other cells of the box.
Find 8 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 8.
R6C1 is seen by both free ends: 8 is therefore eliminated there.
Look at cell R6C1.
Every other digit already appears in its row, column or box.
Only one option remains: R6C1 = 5.
Look at cell R6C8.
Every other digit already appears in its row, column or box.
Only one option remains: R6C8 = 8.
Look at cell R2C8.
Every other digit already appears in its row, column or box.
Only one option remains: R2C8 = 7.
Look at cell R4C7.
Every other digit already appears in its row, column or box.
Only one option remains: R4C7 = 7.
Look at cell R4C9.
Every other digit already appears in its row, column or box.
Only one option remains: R4C9 = 2.
Look at cell R5C2.
Every other digit already appears in its row, column or box.
Only one option remains: R5C2 = 6.
Look at cell R5C3.
Every other digit already appears in its row, column or box.
Only one option remains: R5C3 = 8.
Look at cell R5C4.
Every other digit already appears in its row, column or box.
Only one option remains: R5C4 = 7.
Look at cell R5C5.
Every other digit already appears in its row, column or box.
Only one option remains: R5C5 = 2.
Look at cell R5C9.
Every other digit already appears in its row, column or box.
Only one option remains: R5C9 = 5.
Look at cell R7C8.
Every other digit already appears in its row, column or box.
Only one option remains: R7C8 = 3.
Look at cell R7C9.
Every other digit already appears in its row, column or box.
Only one option remains: R7C9 = 7.
Look at cell R9C2.
Every other digit already appears in its row, column or box.
Only one option remains: R9C2 = 7.
Look at cell R9C4.
Every other digit already appears in its row, column or box.
Only one option remains: R9C4 = 6.
Look at cell R1C7.
Every other digit already appears in its row, column or box.
Only one option remains: R1C7 = 8.
Look at cell R1C8.
Every other digit already appears in its row, column or box.
Only one option remains: R1C8 = 5.
Look at cell R2C3.
Every other digit already appears in its row, column or box.
Only one option remains: R2C3 = 5.
Look at cell R2C6.
Every other digit already appears in its row, column or box.
Only one option remains: R2C6 = 6.
Look at cell R4C4.
Every other digit already appears in its row, column or box.
Only one option remains: R4C4 = 8.
Look at cell R4C5.
Every other digit already appears in its row, column or box.
Only one option remains: R4C5 = 6.
Look at cell R8C2.
Every other digit already appears in its row, column or box.
Only one option remains: R8C2 = 5.
Look at cell R8C3.
Every other digit already appears in its row, column or box.
Only one option remains: R8C3 = 6.
Look at cell R8C5.
Every other digit already appears in its row, column or box.
Only one option remains: R8C5 = 7.
Look at cell R1C5.
Every other digit already appears in its row, column or box.
Only one option remains: R1C5 = 3.
Look at cell R1C9.
Every other digit already appears in its row, column or box.
Only one option remains: R1C9 = 9.
Look at cell R2C1.
Every other digit already appears in its row, column or box.
Only one option remains: R2C1 = 8.
Look at cell R3C1.
Every other digit already appears in its row, column or box.
Only one option remains: R3C1 = 7.
Look at cell R3C5.
Every other digit already appears in its row, column or box.
Only one option remains: R3C5 = 8.
Look at cell R3C6.
Every other digit already appears in its row, column or box.
Only one option remains: R3C6 = 2.
Look at cell R3C9.
Every other digit already appears in its row, column or box.
Only one option remains: R3C9 = 3.
Look at cell R1C1.
Every other digit already appears in its row, column or box.
Only one option remains: R1C1 = 6.
Look at cell R1C3.
Every other digit already appears in its row, column or box.
Only one option remains: R1C3 = 2.
Look at cell R1C6.
Every other digit already appears in its row, column or box.
Only one option remains: R1C6 = 7.
Look at cell R3C3.
Every other digit already appears in its row, column or box.
Only one option remains: R3C3 = 9.