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

Number 2 is the only value possible in cell (5,8).

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

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

For row 3, number 9 is only possible in cell (8,3)

For row 4, number 9 is only possible in cell (1,4)

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

For column 8, Number 8 is only possible in cell (8,5)

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

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

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

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

For row 2, number 6 is only possible in cell (5,2)

For row 1, number 6 is only possible in cell (9,1)

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

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

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

For row 9, number 4 is only possible in cell (1,9)

For column 7, Number 2 is only possible in cell (7,5)

For box 3, candidates for 1 are all in column 8, so you can remove candidates from other blocks.

For row 4, number 1 is only possible in cell (9,4)

For box 8, candidates for 7 are all in row 9, so you can remove candidates from other blocks.

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

X-Wing in columns for 1.

Swordfish in rows for 7.

Either candidate for cell (4,2) forces 1 into cell (1,2).

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

For row 5, number 1 is only possible in cell (3,5)

Either candidate for cell (5,4) forces 8 into cell (6,1).

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

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

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

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

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

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

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

Number 7 is the only value possible in cell (5,4).

Number 4 is the only value possible in cell (6,5).

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

Number 3 is the only value possible in cell (1,5).

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

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

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

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

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

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

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

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

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

Number 1 is the only value possible in cell (2,7).

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

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

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

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

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