Puzzle Copyright © Kevin Stone

R2C3 can only be <2>

R9C2 can only be <8>

R7C2 can only be <5>

R4C2 can only be <6>

R8C1 can only be <2>

R7C1 can only be <3>

R5C2 can only be <4>

R3C2 can only be <9>

R9C1 can only be <7>

R2C5 is the only square in row 2 that can be <3>

R3C8 is the only square in row 3 that can be <2>

R3C5 is the only square in row 3 that can be <7>

R4C4 is the only square in row 4 that can be <7>

R5C5 is the only square in row 5 that can be <2>

R5C9 is the only square in row 5 that can be <7>

R6C5 is the only square in row 6 that can be <1>

R7C9 is the only square in row 7 that can be <1>

R7C7 is the only square in row 7 that can be <2>

R9C9 is the only square in row 9 that can be <3>

R8C7 is the only square in column 7 that can be <4>

R6C9 is the only square in column 9 that can be <5>

R5C4 is the only square in column 4 that can be <5>

R2C4 is the only square in column 4 that can be <9>

Intersection of row 4 with block 5. The value <9> only appears in one or more of squares R4C4, R4C5 and R4C6 of row 4. These squares are the ones that intersect with block 5. Thus, the other (non-intersecting) squares of block 5 cannot contain this value.

R5C6 - removing <9> from <369> leaving <36>

Intersection of column 7 with block 6. The value <8> only appears in one or more of squares R4C7, R5C7 and R6C7 of column 7. These squares are the ones that intersect with block 6. Thus, the other (non-intersecting) squares of block 6 cannot contain this value.

R5C8 - removing <8> from <3689> leaving <369>

R6C8 - removing <8> from <368> leaving <36>

Intersection of column 9 with block 3. The values <46> only appears in one or more of squares R1C9, R2C9 and R3C9 of column 9. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain these values.

R1C8 - removing <6> from <689> leaving <89>

Squares R2C1, R2C9, R1C1 and R1C9 form a Type-3 Unique Rectangle on <46>. Upon close inspection, it is clear that:

(R1C1 or R1C9)<589>, R1C8<89> and R1C3<58> form a locked triplet on <589> in row 1. No other squares in the row can contain these possibilities

R1C5 - removing <5> from <45> leaving <4>

R3C6 can only be <5>

R8C6 can only be <9>

R8C9 can only be <8>

R4C6 can only be <3>

R9C5 can only be <6>

R8C5 can only be <5>

R3C9 can only be <4>

R7C8 can only be <6>

R9C7 can only be <9>

R7C5 can only be <8>

R2C9 can only be <6>

R5C6 can only be <6>

R5C7 can only be <8>

R6C6 can only be <4>

R5C1 can only be <1>

R6C7 can only be <6>

R6C4 can only be <8>

R6C8 can only be <3>

R5C8 can only be <9>

R7C4 can only be <4>

R4C5 can only be <9>

R2C1 can only be <4>

R1C9 can only be <9>

R5C3 can only be <3>

R3C1 can only be <8>

R1C8 can only be <8>

R1C3 can only be <5>

R3C3 can only be <1>

R4C1 can only be <5>

R4C3 can only be <8>

R1C1 can only be <6>