Step-by-Step Solution

for Tuesday 9th December Diabolical

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

Single Candidate

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

Single Candidate

For row 5, number 9 is only possible in cell (7,5)

Single Position

For column 4, Number 9 is only possible in cell (4,7)

Single Position

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

Single Position

For column 3, Number 3 is only possible in cell (3,1)

Single Position

For row 7, number 1 is only possible in cell (8,7)

Single Position

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

Single Position

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

Single Candidate

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

Single Position

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

Single Position

For box 6, Number 3 is only possible in cell (7,6)

Single Position

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

Single Position

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

Single Position

For column 4, Number 8 is only possible in cell (4,5)

Single Position

For column 1, Number 8 is only possible in cell (1,3)

Single Position

For row 5, number 3 is only possible in cell (6,5)

Single Position

For box 5, Number 4 is only possible in cell (5,6)

Single Position

For box 6, candidates for 8 are all in row 4, so you can remove candidates from other blocks.

Candidate Lines

For box 9, candidates for 5 are all in row 8, so you can remove candidates from other blocks.

Candidate Lines

For box 9, candidates for 4 are all in row 9, so you can remove candidates from other blocks.

Candidate Lines

For blocks 4 and 7, candidates for 4 are all in the same two columns (1 and 3)

Double Pairs

Hidden Pair for 5 and 7, can remove other candidates from these cells.

Hidden Pairs

Either candidate for cell (9,3) forces 4 into cell (8,2).

Forcing Chains

For row 9, number 4 is only possible in cell (7,9)

Single Position

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

Multiple Lines

Either candidate for cell (1,1) forces 2 into cell (1,2).

Forcing Chains

Either candidate for cell (5,4) forces 2 into cell (9,3).

Forcing Chains

Number 5 is the only value possible in cell (8,1).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 1 is the only value possible in cell (7,2).

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (2,4).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (3,4).

Single Candidate

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

Single Candidate

Number 1 is the only value possible in cell (2,6).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 3 is the only value possible in cell (4,9).

Single Candidate

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

Single Candidate