Step-by-Step Solution

for Monday 15th December Diabolical

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

Single Candidate

Number 7 is the only value possible in cell (4,6).

Single Candidate

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

Single Candidate

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

Single Position

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

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

Single Position

For box 6, Number 2 is only possible in cell (9,5)

Single Position

Number 7 is the only value possible in cell (3,5).

Single Candidate

For row 6, number 4 is only possible in cell (2,6)

Single Position

For column 8, Number 4 is only possible in cell (8,9)

Single Position

For column 8, Number 7 is only possible in cell (8,3)

Single Position

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

Single Position

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

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 6 is the only value possible in cell (7,3).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 9, number 1 is only possible in cell (6,9)

Single Position

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

Single Position

For box 8, candidates for 5 are all in column 5, so you can remove candidates from other blocks.

Candidate Lines

For blocks 2 and 5, candidates for 6 are all in the same two columns (5 and 6)

Double Pairs

Candidates for 9 in boxes 2 and 5 force the candidates in box 8 to be in the remaining line.

Multiple Lines

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Either candidate for cell (3,1) forces 5 into cell (5,8).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 4 is the only value possible in cell (1,3).

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (6,3).

Single Candidate

Number 8 is the only value possible in cell (6,4).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate