Number 3 is the only value possible in cell (7,8).

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

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

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

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

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

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

For row 9, number 7 is only possible in cell (4,9)

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

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

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

For row 3, number 2 is only possible in cell (9,3)

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

For row 5, number 3 is only possible in cell (9,5)

For column 9, Number 4 is only possible in cell (9,6)

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

For box 6, Number 7 is only possible in cell (7,5)

For box 8, Number 1 is only possible in cell (5,9)

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

Number 2 is the only value possible in cell (1,9).

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

For column 2, Number 5 is only possible in cell (2,9)

For column 7, Number 5 is only possible in cell (7,1)

For box 8, candidates for 4 are all in column 6, so you can remove candidates from other blocks.

For blocks 2 and 3, candidates for 1 are all in the same two rows (1 and 3)

X-Wing in rows for 6.

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

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

Number 4 is the only value possible in cell (3,5).

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

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

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

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

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

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

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

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

Number 1 is the only value possible in cell (4,3).

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

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

Number 9 is the only value possible in cell (4,1).

Number 8 is the only value possible in cell (6,1).

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

Number 1 is the only value possible in cell (7,4).

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

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

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

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

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

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

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

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

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

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

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

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