Step-by-Step Solution
for Sunday 22nd December Tricky


Before

Step

After


Sudoku puzzle
First step:
Add in all possible valid pencilmarks.
Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (9,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (7,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (6,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (8,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (1,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (1,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (1,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (1,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (9,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (1,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (9,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (9,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (1,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (9,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (9,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

For row 1, number 5 is only possible in cell (3,1)

Single Position

Sudoku puzzle

Sudoku puzzle

For box 9, candidates for 9 are all in column 7, so you can remove candidates from other blocks.

Candidate Lines

Sudoku puzzle

Sudoku puzzle

Hidden Pair for 1 and 4, can remove other candidates from these cells.

Hidden Pairs

Sudoku puzzle

Sudoku puzzle

For box 2, candidates for 3 are all in row 1, so you can remove candidates from other blocks.

Candidate Lines

Sudoku puzzle

Sudoku puzzle

For box 3, candidates for 3 are all in row 2, so you can remove candidates from other blocks.

Candidate Lines

Sudoku puzzle

Sudoku puzzle

Naked Pair for 1 and 4, can remove these as candidates from other cells.

Naked Pairs

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (5,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

For row 5, number 8 is only possible in cell (3,5)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 8, number 8 is only possible in cell (4,8)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 5, number 9 is only possible in cell (8,5)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 6, number 9 is only possible in cell (3,6)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 5, number 3 is only possible in cell (7,5)

Single Position

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (7,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (8,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (6,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (5,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (4,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (3,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (8,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (4,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (4,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (4,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (8,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (3,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (2,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (2,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (7,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (6,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (2,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (2,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (3,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (5,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (5,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (6,2).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (6,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (7,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (8,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (3,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (5,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (2,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (7,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (2,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (4,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 3 is the only value possible in cell (5,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (6,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (7,9).

Single Candidate

Sudoku puzzle


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