Number 5 is the only value possible in cell (7,8).

For row 4, number 8 is only possible in cell (6,4)

For row 5, number 8 is only possible in cell (7,5)

For row 9, number 5 is only possible in cell (6,9)

For column 9, Number 5 is only possible in cell (9,1)

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

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

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

For row 3, number 8 is only possible in cell (2,3)

For column 1, Number 8 is only possible in cell (1,9)

For row 2, number 5 is only possible in cell (3,2)

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

For column 3, Number 2 is only possible in cell (3,5)

For row 2, number 9 is only possible in cell (5,2)

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

For column 3, Number 9 is only possible in cell (3,8)

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

For column 9, Number 2 is only possible in cell (9,6)

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

For row 1, number 8 is only possible in cell (5,1)

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

For row 8, number 6 is only possible in cell (5,8)

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

For box 2, candidates for 1 are all in column 6, so you can remove candidates from other blocks.

For box 5, candidates for 7 are all in row 5, so you can remove candidates from other blocks.

For box 6, candidates for 7 are all in row 4, so you can remove candidates from other blocks.

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

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

X-Wing in rows for 4.

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

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

Swordfish in rows for 6.

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

Number 1 is the only value possible in cell (8,7).

Number 7 is the only value possible in cell (8,4).

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

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

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

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

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

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

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

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

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

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

Number 3 is the only value possible in cell (9,5).

Number 4 is the only value possible in cell (8,5).

Number 7 is the only value possible in cell (1,6).

Number 1 is the only value possible in cell (7,6).

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

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

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

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

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

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

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

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

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

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

Number 7 is the only value possible in cell (9,8).

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

Number 2 is the only value possible in cell (4,9).

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

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