Step-by-Step Solution
for Thursday 24th November Fiendish


Before

Step

After


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

Sudoku puzzle

For row 1, number 7 is only possible in cell (1,1)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 7, number 7 is only possible in cell (9,7)

Single Position

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Sudoku puzzle

For row 1, number 1 is only possible in cell (2,1)

Single Position

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Sudoku puzzle

For column 8, Number 2 is only possible in cell (8,6)

Single Position

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Sudoku puzzle

For box 6, Number 9 is only possible in cell (9,4)

Single Position

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Sudoku puzzle

For row 1, number 3 is only possible in cell (8,1)

Single Position

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Sudoku puzzle

For row 3, number 3 is only possible in cell (2,3)

Single Position

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Sudoku puzzle

For column 9, Number 3 is only possible in cell (9,5)

Single Position

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Sudoku puzzle

For box 2, candidates for 6 are all in row 3, so you can remove candidates from other blocks.

Candidate Lines

Sudoku puzzle

Sudoku puzzle

For box 6, candidates for 8 are all in column 7, so you can remove candidates from other blocks.

Candidate Lines

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Sudoku puzzle

For box 4, candidates for 5 are all in column 1, so you can remove candidates from other blocks.

Candidate Lines

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Sudoku puzzle

Candidates for 8 in boxes 1 and 3 force the candidates in box 2 to be in the remaining line.

Multiple Lines

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Sudoku puzzle

Candidates for 4 in boxes 1 and 3 force the candidates in box 2 to be in the remaining line.

Multiple Lines

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Sudoku puzzle

Hidden Pair for 5 and 6, can remove other candidates from these cells.

Hidden Pairs

Sudoku puzzle

Sudoku puzzle

For row 2, number 8 is only possible in cell (1,2)

Single Position

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Sudoku puzzle

For box 3, candidates for 4 are all in row 3, so you can remove candidates from other blocks.

Candidate Lines

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Sudoku puzzle

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

Hidden Pairs

Sudoku puzzle

Sudoku puzzle

For column 7, Number 5 is only possible in cell (7,2)

Single Position

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

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Sudoku puzzle

Naked Triple for 4, 5 and 8, can remove these as candidates from other cells.

Naked Triples

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Sudoku puzzle

For box 5, candidates for 5 are all in column 4, so you can remove candidates from other blocks.

Candidate Lines

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Sudoku puzzle

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

Single Position

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Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (9,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (8,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (7,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Naked Pair for 6 and 7, can remove these as candidates from other cells.

Naked Pairs

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Sudoku puzzle

Naked Pair for 2 and 9, can remove these as candidates from other cells.

Naked Pairs

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Sudoku puzzle

Number 5 is the only value possible in cell (1,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (4,6).

Single Candidate

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Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (3,6).

Single Candidate

Sudoku puzzle

Sudoku puzzle

For row 4, number 3 is only possible in cell (3,4)

Single Position

Sudoku puzzle

Sudoku puzzle

For column 3, Number 7 is only possible in cell (3,5)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 5, number 5 is only possible in cell (4,5)

Single Position

Sudoku puzzle

Sudoku puzzle

For row 8, number 1 is only possible in cell (3,8)

Single Position

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (3,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (1,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (5,3).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 7 is the only value possible in cell (5,4).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (4,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (5,1).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (1,5).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (1,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 1 is the only value possible in cell (6,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 2 is the only value possible in cell (1,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 9 is the only value possible in cell (4,8).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 5 is the only value possible in cell (2,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 8 is the only value possible in cell (5,7).

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

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

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 4 is the only value possible in cell (6,9).

Single Candidate

Sudoku puzzle

Sudoku puzzle

Number 6 is the only value possible in cell (8,9).

Single Candidate

Sudoku puzzle


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