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

For row 3, number 2 is only possible in cell (1,3)

For row 1, number 3 is only possible in cell (7,1)

For row 7, number 3 is only possible in cell (3,7)

For column 1, Number 3 is only possible in cell (1,4)

For row 2, number 4 is only possible in cell (7,2)

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

For row 9, number 4 is only possible in cell (8,9)

For row 7, number 4 is only possible in cell (2,7)

For box 6, candidates for 1 are all in row 6, so you can remove candidates from other blocks.

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

For box 7, candidates for 6 are all in column 1, so you can remove candidates from other blocks.

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

For box 7, Number 5 is only possible in cell (3,8)

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

For row 3, number 7 is only possible in cell (8,3)

For column 8, Number 8 is only possible in cell (8,7)

For row 9, number 8 is only possible in cell (4,9)

For column 4, Number 1 is only possible in cell (4,5)

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

For row 4, number 7 is only possible in cell (6,4)

For row 6, number 7 is only possible in cell (9,6)

For row 9, number 7 is only possible in cell (3,9)

For row 6, number 1 is only possible in cell (7,6)

For row 4, number 2 is only possible in cell (5,4)

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

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

Number 6 is the only value possible in cell (7,3).

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

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

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

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

Number 9 is the only value possible in cell (3,2).

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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