Copyright © Kevin Stone

R5C4 can only be <5>

R5C5 can only be <4>

R5C6 can only be <1>

R1C7 is the only square in row 1 that can be <4>

R3C4 is the only square in row 3 that can be <2>

R3C9 is the only square in row 3 that can be <5>

R4C7 is the only square in row 4 that can be <1>

R4C3 is the only square in row 4 that can be <4>

R6C3 is the only square in row 6 that can be <5>

R8C9 is the only square in row 8 that can be <4>

R7C6 is the only square in row 7 that can be <4>

R9C5 is the only square in row 9 that can be <5>

R1C5 is the only square in column 5 that can be <8>

R3C7 is the only square in column 7 that can be <9>

R7C9 is the only square in column 9 that can be <6>

R7C4 can only be <7>

R7C7 can only be <3>

R9C8 is the only square in block 9 that can be <8>

R5C2 is the only square in column 2 that can be <8>

R6C9 is the only square in row 6 that can be <8>

Squares R4C5 and R6C5 in column 5 form a simple locked pair. These 2 squares both contain the 2 possibilities <67>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.

R2C5 - removing <67> from <3679> leaving <39>

Intersection of row 2 with block 1. The value <6> only appears in one or more of squares R2C1, R2C2 and R2C3 of row 2. These squares are the ones that intersect with block 1. Thus, the other (non-intersecting) squares of block 1 cannot contain this value.

R1C2 - removing <6> from <679> leaving <79>

R2C2 is the only square in column 2 that can be <6>

Intersection of column 2 with block 7. The value <2> only appears in one or more of squares R7C2, R8C2 and R9C2 of column 2. These squares are the ones that intersect with block 7. Thus, the other (non-intersecting) squares of block 7 cannot contain this value.

R8C1 - removing <2> from <2379> leaving <379>

Intersection of block 4 with column 1. The values <269> only appears in one or more of squares R4C1, R5C1 and R6C1 of block 4. These squares are the ones that intersect with column 1. Thus, the other (non-intersecting) squares of column 1 cannot contain these values.

R2C1 - removing <9> from <1379> leaving <137>

R8C1 - removing <9> from <379> leaving <37>

R2C5 is the only square in row 2 that can be <9>

R8C5 can only be <3>

R1C4 can only be <6>

R8C1 can only be <7>

R9C6 can only be <6>

R9C4 can only be <9>

R8C8 can only be <2>

R8C2 can only be <9>

R5C8 can only be <3>

R9C7 can only be <7>

R9C2 can only be <2>

R9C3 can only be <3>

R6C7 can only be <2>

R5C9 can only be <9>

R5C1 can only be <2>

R4C9 can only be <7>

R6C1 can only be <6>

R1C2 can only be <7>

R3C3 can only be <8>

R1C6 can only be <3>

R1C8 can only be <1>

R3C6 can only be <7>

R1C3 can only be <9>

R2C8 can only be <7>

R2C9 can only be <3>

R2C1 can only be <1>

R3C1 can only be <3>

R7C3 can only be <1>

R4C5 can only be <6>

R6C5 can only be <7>

R4C1 can only be <9>

R7C1 can only be <8>