Puzzle Copyright © Kevin Stone

R1C4 can only be <2>

R2C5 can only be <3>

R2C6 can only be <8>

R3C2 can only be <2>

R3C6 can only be <6>

R8C5 can only be <7>

R5C5 can only be <5>

R1C7 is the only square in row 1 that can be <6>

R9C1 is the only square in row 9 that can be <3>

R8C4 is the only square in row 8 that can be <3>

R8C2 is the only square in column 2 that can be <1>

R4C2 is the only square in column 2 that can be <3>

R1C2 is the only square in column 2 that can be <8>

R6C8 is the only square in column 8 that can be <8>

R6C7 is the only square in row 6 that can be <3>

R3C7 can only be <5>

R3C8 can only be <3>

R1C9 can only be <7>

R1C1 can only be <5>

R8C8 is the only square in row 8 that can be <5>

Squares R6C1 and R6C6 in row 6 form a simple locked pair. These 2 squares both contain the 2 possibilities <79>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.

R6C3 - removing <79> from <2579> leaving <25>

R6C4 - removing <9> from <19> leaving <1>

R6C9 - removing <9> from <1259> leaving <125>

Intersection of column 1 with block 4. The value <7> only appears in one or more of squares R4C1, R5C1 and R6C1 of column 1. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain this value.

R4C3 - removing <7> from <5789> leaving <589>

R5C2 - removing <7> from <679> leaving <69>

R5C3 - removing <7> from <2679> leaving <269>

Intersection of row 5 with block 6. The value <7> only appears in one or more of squares R5C7, R5C8 and R5C9 of row 5. These squares are the ones that intersect with block 6. Thus, the other (non-intersecting) squares of block 6 cannot contain this value.

R4C7 - removing <7> from <179> leaving <19>

R5C7 is the only square in column 7 that can be <7>

R5C8 can only be <2>

R6C9 can only be <5>

R6C3 can only be <2>

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

R4C3 is the only square in row 4 that can be <5>

R4C1 is the only square in row 4 that can be <8>

R8C1 can only be <9>

R8C7 can only be <4>

R6C1 can only be <7>

R8C3 can only be <8>

R2C7 can only be <1>

R7C8 can only be <7>

R2C8 can only be <4>

R4C7 can only be <9>

R4C4 can only be <4>

R4C9 can only be <1>

R9C9 can only be <9>

R6C6 can only be <9>

R9C6 can only be <4>

R7C2 can only be <6>

R9C8 can only be <1>

R9C3 can only be <7>

R4C6 can only be <7>

R7C4 can only be <9>

R7C3 can only be <4>

R5C2 can only be <9>

R2C3 can only be <9>

R2C2 can only be <7>

R5C3 can only be <6>