Step-by-Step Solution

for Sunday 7th December Fiendish

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

Single Candidate

For row 4, number 8 is only possible in cell (3,4)

Single Position

For row 7, number 8 is only possible in cell (2,7)

Single Position

For row 9, number 8 is only possible in cell (4,9)

Single Position

For row 4, number 7 is only possible in cell (6,4)

Single Position

For row 6, number 7 is only possible in cell (2,6)

Single Position

For column 9, Number 7 is only possible in cell (9,2)

Single Position

For row 2, number 8 is only possible in cell (7,2)

Single Position

For row 6, number 8 is only possible in cell (9,6)

Single Position

For row 5, number 4 is only possible in cell (6,5)

Single Position

For row 5, number 3 is only possible in cell (4,5)

Single Position

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

Single Position

For row 5, number 2 is only possible in cell (8,5)

Single Position

For box 1, candidates for 4 are all in column 3, so you can remove candidates from other blocks.

Candidate Lines

Candidates for 5 in boxes 4 and 6 force the candidates in box 5 to be in the remaining line.

Multiple Lines

Hidden Pair for 3 and 7, can remove other candidates from these cells.

Hidden Pairs

Naked Triple for 1, 5 and 6, can remove these as candidates from other cells.

Naked Triples

For column 9, Number 6 is only possible in cell (9,1)

Single Position

For row 2, number 6 is only possible in cell (1,2)

Single Position

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

Single Candidate

For row 5, number 6 is only possible in cell (2,5)

Single Position

For row 9, number 6 is only possible in cell (8,9)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 6, number 6 is only possible in cell (4,6)

Single Position

For row 8, number 6 is only possible in cell (3,8)

Single Position

For row 9, number 3 is only possible in cell (5,9)

Single Position

For row 1, number 3 is only possible in cell (6,1)

Single Position

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

Single Position

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

Single Candidate

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

Single Candidate

For column 4, Number 9 is only possible in cell (4,3)

Single Position

For row 2, number 2 is only possible in cell (4,2)

Single Position

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

Single Candidate

Number 5 is the only value possible in cell (6,2).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 3, number 1 is only possible in cell (2,3)

Single Position

For row 3, number 2 is only possible in cell (7,3)

Single Position

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

Single Position

Number 9 is the only value possible in cell (2,8).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (3,1).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 9 is the only value possible in cell (1,4).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 4 is the only value possible in cell (1,9).

Single Candidate

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

Single Candidate

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

Single Candidate