Step-by-Step Solution

for Sunday 15th December Fiendish

For column 8, Number 9 is only possible in cell (8,7)

Single Position

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

Single Position

For column 7, Number 5 is only possible in cell (7,4)

Single Position

For column 8, Number 6 is only possible in cell (8,1)

Single Position

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

Single Position

For column 6, Number 8 is only possible in cell (6,3)

Single Position

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

Single Candidate

For row 3, number 6 is only possible in cell (4,3)

Single Position

For row 4, number 2 is only possible in cell (8,4)

Single Position

For row 3, number 4 is only possible in cell (9,3)

Single Position

For box 7, candidates for 5 are all in row 9, so you can remove candidates from other blocks.

Candidate Lines

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

Candidate Lines

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

Multiple Lines

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

Naked Pairs

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

Single Candidate

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

Candidate Lines

For box 4, candidates for 4 are all in column 2, so you can remove candidates from other blocks.

Candidate Lines

For blocks 4 and 6, candidates for 1 are all in the same two rows (5 and 6)

Double Pairs

Naked Pair for 1 and 9, can remove these as candidates from other cells.

Naked Pairs

For box 1, Number 9 is only possible in cell (2,1)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (8,6).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (3,2).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 9 is the only value possible in cell (5,8).

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (2,9).

Single Candidate

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

Single Candidate

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

Single Candidate