Copyright © Kevin Stone

R2C1 is the only square in row 2 that can be <7>

R4C8 is the only square in row 4 that can be <6>

R5C1 is the only square in row 5 that can be <4>

R7C2 is the only square in row 7 that can be <3>

R1C1 is the only square in row 1 that can be <3>

R7C3 is the only square in row 7 that can be <2>

R8C9 is the only square in row 8 that can be <1>

R3C1 is the only square in column 1 that can be <2>

R4C1 is the only square in column 1 that can be <8>

R9C3 is the only square in column 3 that can be <6>

R9C8 is the only square in column 8 that can be <3>

R9C9 is the only square in row 9 that can be <4>

R1C5 is the only square in row 1 that can be <4>

R2C8 is the only square in row 2 that can be <4>

R2C5 is the only square in row 2 that can be <1>

R2C4 is the only square in row 2 that can be <2>

R9C4 can only be <5>

R9C1 can only be <9>

R3C4 can only be <8>

R2C6 can only be <9>

R9C7 can only be <7>

R8C1 can only be <5>

R9C5 can only be <2>

R2C9 can only be <8>

R1C6 can only be <5>

R8C2 can only be <7>

R8C6 can only be <6>

R8C4 can only be <3>

R7C6 can only be <7>

R5C6 can only be <8>

R8C5 can only be <9>

R5C4 can only be <6>

R1C3 is the only square in row 1 that can be <8>

R3C7 is the only square in row 3 that can be <5>

R5C5 is the only square in row 5 that can be <3>

R6C7 is the only square in row 6 that can be <8>

Squares R1C9 and R7C9 in column 9 form a simple locked pair. These 2 squares both contain the 2 possibilities <69>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.

R5C9 - removing <9> from <259> leaving <25>

Intersection of row 4 with block 4. The value <9> only appears in one or more of squares R4C1, R4C2 and R4C3 of row 4. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain this value.

R5C2 - removing <9> from <1259> leaving <125>

R5C3 - removing <9> from <179> leaving <17>

Squares R5C3<17>, R5C7<19> and R5C8<179> in row 5 form a comprehensive locked triplet. These 3 squares can only contain the 3 possibilities <179>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.

R5C2 - removing <1> from <125> leaving <25>

Squares R5C2, R5C9, R6C2 and R6C9 form a Type-1 Unique Rectangle on <25>.

R6C2 - removing <25> from <125> leaving <1>

R6C8 can only be <7>

R1C2 can only be <9>

R5C3 can only be <7>

R6C5 can only be <5>

R1C9 can only be <6>

R4C2 can only be <5>

R3C3 can only be <1>

R1C7 can only be <1>

R7C9 can only be <9>

R3C8 can only be <9>

R5C8 can only be <1>

R4C5 can only be <7>

R5C2 can only be <2>

R4C3 can only be <9>

R5C9 can only be <5>

R5C7 can only be <9>

R6C9 can only be <2>

R7C7 can only be <6>