Step-by-Step Solution

for Wednesday 9th September Diabolical

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

Single Candidate

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

Single Position

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

Single Position

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

Single Position

For row 3, number 4 is only possible in cell (8,3)

Single Position

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

Candidate Lines

Candidates for 9 in boxes 2 and 3 force the candidates in box 1 to be in the remaining line.

Multiple Lines

Candidates for 7 in boxes 2 and 3 force the candidates in box 1 to be in the remaining line.

Multiple Lines

Naked Pair for 3 and 4, can remove these as candidates from other cells.

Naked Pairs

Naked Pair for 6 and 9, can remove these as candidates from other cells.

Naked Pairs

For row 7, number 9 is only possible in cell (8,7)

Single Position

Naked Pair for 6 and 9, can remove these as candidates from other cells.

Naked Pairs

Hidden Pair for 7 and 8, can remove other candidates from these cells.

Hidden Pairs

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

Single Position

For row 7, number 5 is only possible in cell (2,7)

Single Position

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

Single Position

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

Single Candidate

For row 4, number 5 is only possible in cell (3,4)

Single Position

X-Wing in rows for 4.

X-Wings

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

Single Position

Number 3 is the only value possible in cell (5,8).

Single Candidate

For column 3, Number 4 is only possible in cell (3,8)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Position

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

Forcing Chains

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

Single Candidate

Number 2 is the only value possible in cell (1,3).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (6,2).

Single Candidate

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

Single Candidate

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

Multiple Lines

Either candidate for cell (6,4) forces 6 into cell (6,5).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 1 is the only value possible in cell (6,4).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate