Step-by-Step Solution

for Sunday 13th April Fiendish

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

For row 2, number 8 is only possible in cell (7,2)

Single Position

For box 4, Number 8 is only possible in cell (3,5)

Single Position

For row 9, number 8 is only possible in cell (1,9)

Single Position

For row 5, number 1 is only possible in cell (2,5)

Single Position

For row 5, number 4 is only possible in cell (8,5)

Single Position

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

Single Position

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

Single Position

For row 9, number 4 is only possible in cell (3,9)

Single Position

For box 3, candidates for 1 are all in column 8, so you can remove candidates from other blocks.

Candidate Lines

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

Single Position

For box 2, candidates for 5 are all in row 3, so you can remove candidates from other blocks.

Candidate Lines

For box 4, candidates for 5 are all in row 6, so you can remove candidates from other blocks.

Candidate Lines

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

Candidate Lines

For box 4, candidates for 2 are all in row 6, so you can remove candidates from other blocks.

Candidate Lines

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

Naked Pairs

Number 9 is the only value possible in cell (5,6).

Single Candidate

Naked Pair for 2 and 6, can remove these as candidates from other cells.

Naked Pairs

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

Candidate Lines

Candidates for 2 in boxes 4 and 6 force the candidates in box 5 to be in the remaining line.

Multiple Lines

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

Naked Pairs

For row 9, number 3 is only possible in cell (8,9)

Single Position

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 7 is the only value possible in cell (6,5).

Single Candidate

Number 3 is the only value possible in cell (4,6).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 5 is the only value possible in cell (6,7).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 9 is the only value possible in cell (3,1).

Single Candidate

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

Single Candidate

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

Single Candidate

Number 3 is the only value possible in cell (9,1).

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

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

Single Candidate

Number 7 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 6 is the only value possible in cell (7,9).

Single Candidate