Sudoku Puzzle © Kevin Stone

R4C9 can only be <8>

R6C6 can only be <2>

R5C9 can only be <5>

R6C9 can only be <4>

R5C8 can only be <1>

R6C4 can only be <8>

R4C6 can only be <3>

R4C4 can only be <6>

R4C1 can only be <2>

R9C6 can only be <4>

R6C1 can only be <7>

R1C4 can only be <2>

R5C5 can only be <9>

R1C6 can only be <5>

R9C4 can only be <9>

R1C1 is the only square in row 1 that can be <1>

R3C7 is the only square in row 3 that can be <1>

R7C3 is the only square in row 7 that can be <5>

R2C3 is the only square in column 3 that can be <7>

R2C9 is the only square in row 2 that can be <2>

Squares R5C1 and R9C1 in column 1 form a simple locked pair. These 2 squares both contain the 2 possibilities <68>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.

R2C1 - removing <8> from <489> leaving <49>

R8C1 - removing <8> from <489> leaving <49>

Squares R8C3<28>, R9C1<68> and R9C2<268> in block 7 form a comprehensive locked triplet. These 3 squares can only contain the 3 possibilities <268>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.

R7C2 - removing <2> from <249> leaving <49>

R7C8 is the only square in row 7 that can be <2>

Intersection of column 8 with block 3. The value <4> only appears in one or more of squares R1C8, R2C8 and R3C8 of column 8. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain this value.

R2C7 - removing <4> from <489> leaving <89>

Squares R2C1 and R7C7 form a remote locked pair. <49> can be removed from any square that is common to their groups.

R2C7 - removing <9> from <89> leaving <8>

R2C5 can only be <4>

R3C8 can only be <4>

R1C8 can only be <7>

R1C9 can only be <9>

R9C8 can only be <8>

R8C9 can only be <3>

R2C1 can only be <9>

R1C5 can only be <8>

R8C5 can only be <2>

R9C9 can only be <7>

R9C1 can only be <6>

R1C2 can only be <4>

R8C1 can only be <4>

R8C7 can only be <9>

R7C2 can only be <9>

R8C3 can only be <8>

R9C5 can only be <3>

R7C7 can only be <4>

R9C2 can only be <2>

R5C1 can only be <8>

R3C2 can only be <8>

R3C3 can only be <2>

R5C2 can only be <6>