Step-by-Step Solution

for Friday 15th May Diabolical

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Position

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

Single Position

For row 7, number 1 is only possible in cell (2,7)

Single Position

For box 2, candidates for 2 are all in column 5, so you can remove candidates from other blocks.

Candidate Lines

For box 2, candidates for 8 are all in column 6, so you can remove candidates from other blocks.

Candidate Lines

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

Naked Pairs

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

Single Candidate

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

Hidden Pairs

For box 1, candidates for 4 are all in column 3, so you can remove candidates from other blocks.

Candidate Lines

Candidates for 5 in boxes 1 and 4 force the candidates in box 7 to be in the remaining line.

Multiple Lines

Hidden Pair for 3 and 5, can remove other candidates from these cells.

Hidden Pairs

Naked Triple for 3, 7 and 8, can remove these as candidates from other cells.

Naked Triples

For box 4, Number 8 is only possible in cell (2,5)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 8, number 9 is only possible in cell (5,8)

Single Position

Either candidate for cell (2,2) forces 8 into cell (7,6).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 2, number 7 is only possible in cell (9,2)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 4 is the only value possible in cell (3,2).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 4 is the only value possible in cell (9,1).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 8 is the only value possible in cell (9,7).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (6,8).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate