Copyright © Kevin Stone

R1C7 is the only square in row 1 that can be <8>

R5C6 is the only square in row 5 that can be <8>

R7C3 is the only square in row 7 that can be <8>

R9C3 is the only square in row 9 that can be <3>

R8C3 is the only square in column 3 that can be <2>

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

R8C7 can only be <1>

R8C5 can only be <9>

R1C5 can only be <7>

R2C5 can only be <1>

R1C1 is the only square in row 1 that can be <9>

R9C1 is the only square in row 9 that can be <1>

R7C2 can only be <4>

R7C1 can only be <5>

R7C6 can only be <1>

R7C4 can only be <6>

R4C6 can only be <9>

R3C6 can only be <3>

R9C5 can only be <4>

R6C5 can only be <2>

R3C4 can only be <9>

R6C6 can only be <4>

R6C3 can only be <7>

R6C4 can only be <3>

R6C7 can only be <9>

R2C3 can only be <4>

R5C1 can only be <4>

R2C7 can only be <7>

R3C1 can only be <7>

R4C7 can only be <5>

R7C7 can only be <2>

R4C5 can only be <6>

R9C7 can only be <6>

R7C8 can only be <7>

R5C8 can only be <2>

R9C9 can only be <5>

R3C7 can only be <4>

R1C9 can only be <6>

R1C3 can only be <5>

R3C9 can only be <2>

R3C8 can only be <5>

R5C9 can only be <7>

R4C3 can only be <1>

R5C5 can only be <5>

R5C4 can only be <1>

R4C4 can only be <7>

R3C3 can only be <6>

R5C2 can only be <6>

R3C2 can only be <1>