For row 1, number 6 is only possible in cell (3,1)

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

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

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

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

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

Number 4 is the only value possible in cell (6,9).

Number 7 is the only value possible in cell (5,9).

For row 2, number 8 is only possible in cell (4,2)

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

For column 9, Number 7 is only possible in cell (9,4)

For column 4, Number 7 is only possible in cell (4,5)

For column 4, Number 6 is only possible in cell (4,8)

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

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

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

Number 2 is the only value possible in cell (8,7).

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

Number 5 is the only value possible in cell (9,8).

For column 7, Number 2 is only possible in cell (7,3)

For row 4, number 1 is only possible in cell (8,4)

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

Naked Pair for 2 and 9, can remove these as candidates from other cells.

For box 1, candidates for 2 are all in column 1, so you can remove candidates from other blocks.

Naked Pair for 3 and 9, can remove these as candidates from other cells.

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

Naked Pair for 3 and 9, can remove these as candidates from other cells.

Hidden Pair for 1 and 5, can remove other candidates from these cells.

For box 4, candidates for 9 are all in column 2, so you can remove candidates from other blocks.

Swordfish in columns for 3.

Either candidate for cell (4,1) forces 4 into cell (5,1).

For row 3, number 4 is only possible in cell (1,3)

Either candidate for cell (4,1) forces 8 into cell (5,4).

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

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

Number 2 is the only value possible in cell (4,1).

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

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

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

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

Number 7 is the only value possible in cell (8,2).

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

Number 7 is the only value possible in cell (2,3).

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

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

Number 9 is the only value possible in cell (7,4).

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

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

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

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

Number 2 is the only value possible in cell (6,5).

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

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

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

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

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

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

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

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

Number 3 is the only value possible in cell (7,9).

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