Copyright © Kevin Stone

R5C5 is the only square in row 5 that can be <1>

R5C6 is the only square in row 5 that can be <7>

R5C4 is the only square in row 5 that can be <3>

R9C4 can only be <8>

R1C4 can only be <4>

R5C2 is the only square in row 5 that can be <6>

R5C8 is the only square in row 5 that can be <2>

R8C9 is the only square in row 8 that can be <2>

R5C7 is the only square in block 6 that can be <9>

R5C3 can only be <5>

R7C3 can only be <4>

R8C3 can only be <1>

R2C3 can only be <8>

R3C3 can only be <9>

R1C2 can only be <7>

R1C1 can only be <1>

R8C2 can only be <3>

R7C2 can only be <5>

R1C9 can only be <3>

R1C6 can only be <8>

R7C7 can only be <3>

R9C2 can only be <9>

R1C8 can only be <9>

R4C6 can only be <4>

R3C5 can only be <2>

R3C2 can only be <4>

R2C5 can only be <3>

R4C9 can only be <5>

R6C6 can only be <6>

R4C4 can only be <2>

R6C9 can only be <4>

R9C9 can only be <7>

R6C5 can only be <9>

R9C6 can only be <3>

R9C1 can only be <6>

R2C9 can only be <1>

R7C8 can only be <6>

R2C2 can only be <2>

R4C1 can only be <9>

R6C4 can only be <5>

R6C1 can only be <2>

R4C5 can only be <8>

R7C5 can only be <7>

R9C8 can only be <5>

R8C1 can only be <7>

R3C8 can only be <8>

R2C1 can only be <5>

R3C7 can only be <5>

R8C8 can only be <4>

R8C5 can only be <6>

R8C7 can only be <8>

R2C8 can only be <7>

R2C7 can only be <4>