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

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

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

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

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

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

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

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

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

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

For column 9, Number 7 is only possible in cell (9,9)

For column 6, Number 7 is only possible in cell (6,8)

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

For row 6, number 2 is only possible in cell (1,6)

For box 8, candidates for 5 are all in column 5, so you can remove candidates from other blocks.

For box 6, candidates for 1 are all in row 5, so you can remove candidates from other blocks.

For box 6, candidates for 3 are all in column 9, so you can remove candidates from other blocks.

For blocks 5 and 8, candidates for 4 are all in the same two columns (5 and 6)

Either candidate for cell (6,1) forces 5 into cell (3,5).

For column 3, Number 6 is only possible in cell (3,2)

For box 3, candidates for 6 are all in column 9, so you can remove candidates from other blocks.

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

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

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

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

X-Wing in columns for 2.

X-Wing in columns for 3.

Either candidate for cell (6,9) forces 7 into cell (5,2).

For row 5, number 7 is only possible in cell (1,5)

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

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

Either candidate for cell (1,4) forces 3 into cell (3,7).

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

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

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

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

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

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

Number 3 is the only value possible in cell (2,5).

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

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

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

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

Number 1 is the only value possible in cell (9,5).

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

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

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

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

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

Number 5 is the only value possible in cell (4,1).

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

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

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

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

Number 6 is the only value possible in cell (5,3).

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

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

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

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

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

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

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

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

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

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