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

For row 4, number 1 is only possible in cell (6,4)

For row 4, number 5 is only possible in cell (3,4)

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

For row 6, number 5 is only possible in cell (4,6)

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

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

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

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

For row 5, number 2 is only possible in cell (7,5)

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

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

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

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

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

For blocks 6 and 9, candidates for 6 are all in the same two columns (8 and 7)

Hidden Pair for 3 and 8, can remove other candidates from these cells.

For column 3, Number 1 is only possible in cell (3,7)

Hidden Pair for 2 and 5, can remove other candidates from these cells.

Either candidate for cell (1,8) forces 2 into cell (1,9).

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

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

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

Either candidate for cell (8,5) forces 7 into cell (5,8).

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

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

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

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

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

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

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

For row 2, number 3 is only possible in cell (7,2)

Naked Pair for 4 and 9, can remove these as candidates from other cells.

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

For row 1, number 1 is only possible in cell (4,1)

Either candidate for cell (6,1) forces 4 into cell (7,1).

Number 9 is the only value possible in cell (8,3).

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

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

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

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

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

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

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

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

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

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

Number 9 is the only value possible in cell (6,8).

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

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

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

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

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

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

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

Number 8 is the only value possible in cell (3,9).

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

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

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