Step-by-Step Solution

for Thursday 20th February Diabolical

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

Single Position

For column 4, Number 2 is only possible in cell (4,7)

Single Position

For column 3, Number 9 is only possible in cell (3,1)

Single Position

For column 4, Number 9 is only possible in cell (4,6)

Single Position

For box 5, candidates for 4 are all in row 5, so you can remove candidates from other blocks.

Candidate Lines

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

Candidate Lines

For box 5, candidates for 6 are all in column 6, so you can remove candidates from other blocks.

Candidate Lines

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 6 is the only value possible in cell (5,1).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Position

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

Single Position

For column 1, Number 8 is only possible in cell (1,4)

Single Position

For column 2, Number 8 is only possible in cell (2,3)

Single Position

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

Single Candidate

For box 4, candidates for 7 are all in row 5, so you can remove candidates from other blocks.

Candidate Lines

Candidates for 3 in boxes 5 and 6 force the candidates in box 4 to be in the remaining line.

Multiple Lines

Either candidate for cell (7,5) forces 2 into cell (9,5).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Position

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

Single Candidate

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

Single Position

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

Single Position

For row 9, number 2 is only possible in cell (1,9)

Single Position

Either candidate for cell (8,6) forces 9 into cell (8,4).

Forcing Chains

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

Single Position

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

Single Candidate

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

Single Position

Either candidate for cell (6,5) forces 3 into cell (1,7).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 3 is the only value possible in cell (2,6).

Single Candidate

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

Single Candidate

Number 1 is the only value possible in cell (3,8).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate