Step-by-Step Solution

for Monday 21st July Diabolical

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 1, number 9 is only possible in cell (5,1)

Single Position

For column 4, Number 7 is only possible in cell (4,3)

Single Position

For row 4, number 5 is only possible in cell (9,4)

Single Position

For row 4, number 9 is only possible in cell (2,4)

Single Position

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

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For box 3, candidates for 6 are all in column 8, so you can remove candidates from other blocks.

Candidate Lines

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

Candidate Lines

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

Multiple Lines

Naked Pair for 1 and 9, can remove these as candidates from other cells.

Naked Pairs

Naked Triple for 3, 6 and 8, can remove these as candidates from other cells.

Naked Triples

Candidates for 6 in boxes 1 and 4 force the candidates in box 7 to be in the remaining line.

Multiple Lines

Naked Pair for 4 and 7, can remove these as candidates from other cells.

Naked Pairs

Either candidate for cell (2,3) forces 5 into cell (8,9).

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 8, number 6 is only possible in cell (7,8)

Single Position

X-Wing in columns for 2.

X-Wings

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

Forcing Chains

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 1 is the only value possible in cell (7,3).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 2 is the only value possible in cell (9,8).

Single Candidate

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

Single Candidate

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

Single Candidate