Step-by-Step Solution

for Wednesday 17th December Diabolical

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

Single Candidate

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

Single Candidate

Number 8 is the only value possible in cell (6,3).

Single Candidate

Number 2 is the only value possible in cell (9,3).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 9 is the only value possible in cell (1,7).

Single Candidate

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

Single Candidate

For column 9, Number 7 is only possible in cell (9,1)

Single Position

For row 1, number 3 is only possible in cell (4,1)

Single Position

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

Single Position

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

Single Position

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

Single Position

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

Single Position

For row 4, number 7 is only possible in cell (8,4)

Single Position

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

Single Position

For row 2, number 6 is only possible in cell (9,2)

Single Position

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

Single Position

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

Single Position

For box 6, candidates for 9 are all in row 6, so you can remove candidates from other blocks.

Candidate Lines

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

Candidate Lines

Candidates for 1 in boxes 1 and 4 force the candidates in box 7 to be in the remaining line.

Multiple Lines

Candidates for 4 in boxes 2 and 5 force the candidates in box 8 to be in the remaining line.

Multiple Lines

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

Naked Pairs

Either candidate for cell (1,4) forces 9 into cell (3,5).

Forcing Chains

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

Single Position

For column 2, Number 1 is only possible in cell (2,6)

Single Position

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

Single Position

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

Single Candidate

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

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 (3,2).

Single Candidate

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

Single Candidate

Number 8 is the only value possible in cell (7,2).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 8 is the only value possible in cell (3,6).

Single Candidate

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

Single Candidate

Number 2 is the only value possible in cell (1,4).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 2 is the only value possible in cell (8,6).

Single Candidate

Number 9 is the only value possible in cell (7,6).

Single Candidate

Number 5 is the only value possible in cell (9,6).

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (2,8).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 2 is the only value possible in cell (7,8).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 2 is the only value possible in cell (3,9).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (6,9).

Single Candidate

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

Single Candidate