Copyright © Kevin Stone

R1C1 is the only square in row 1 that can be <7>

R2C5 is the only square in row 2 that can be <8>

R3C7 is the only square in row 3 that can be <2>

R4C7 is the only square in row 4 that can be <8>

R7C8 is the only square in row 7 that can be <5>

R7C4 is the only square in row 7 that can be <2>

R9C4 can only be <4>

R8C1 is the only square in row 8 that can be <8>

R9C1 can only be <2>

R8C8 is the only square in row 8 that can be <2>

R9C6 is the only square in row 9 that can be <8>

Squares R8C5 and R9C5 in column 5 form a simple locked pair. These 2 squares both contain the 2 possibilities <67>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.

R4C5 - removing <6> from <2469> leaving <249>

R5C5 - removing <6> from <2469> leaving <249>

R6C5 - removing <6> from <4569> leaving <459>

Intersection of row 1 with block 2. The value <4> only appears in one or more of squares R1C4, R1C5 and R1C6 of row 1. These squares are the ones that intersect with block 2. Thus, the other (non-intersecting) squares of block 2 cannot contain this value.

R3C6 - removing <4> from <345> leaving <35>

Intersection of row 1 with block 3. The value <1> only appears in one or more of squares R1C7, R1C8 and R1C9 of row 1. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain this value.

R2C9 - removing <1> from <1359> leaving <359>

Intersection of row 2 with block 3. The value <9> only appears in one or more of squares R2C7, R2C8 and R2C9 of row 2. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain this value.

R1C8 - removing <9> from <19> leaving <1>

R1C9 - removing <9> from <1359> leaving <135>

Intersection of row 6 with block 4. The value <1> only appears in one or more of squares R6C1, R6C2 and R6C3 of row 6. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain this value.

R4C2 - removing <1> from <1249> leaving <249>

R4C3 - removing <1> from <13469> leaving <3469>

R5C2 - removing <1> from <12479> leaving <2479>

Intersection of column 1 with block 4. The value <4> 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.

R4C2 - removing <4> from <249> leaving <29>

R4C3 - removing <4> from <3469> leaving <369>

R5C2 - removing <4> from <2479> leaving <279>

R6C2 - removing <4> from <1479> leaving <179>

R6C3 - removing <4> from <134679> leaving <13679>

R3C2 is the only square in column 2 that can be <4>

R3C3 can only be <3>

R3C6 can only be <5>

R2C1 can only be <6>

R2C3 can only be <1>

R2C2 can only be <5>

R1C9 is the only square in row 1 that can be <5>

R6C2 is the only square in row 6 that can be <1>

R6C5 is the only square in row 6 that can be <5>

Squares R4C3 and R4C8 in row 4 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 row.

R4C2 - removing <9> from <29> leaving <2>

R4C4 - removing <9> from <139> leaving <13>

R4C5 - removing <9> from <249> leaving <24>

R4C9 - removing <69> from <13469> leaving <134>

R4C5 can only be <4>

R1C5 can only be <9>

R1C4 can only be <3>

R5C5 can only be <2>

R1C6 can only be <4>

R4C4 can only be <1>

R4C9 can only be <3>

R5C4 can only be <9>

R2C9 can only be <9>

R5C2 can only be <7>

R2C7 can only be <3>

R9C9 can only be <6>

R5C8 can only be <6>

R9C2 can only be <9>

R5C6 can only be <3>

R4C8 can only be <9>

R9C5 can only be <7>

R8C9 can only be <4>

R4C3 can only be <6>

R6C8 can only be <7>

R5C1 can only be <4>

R6C6 can only be <6>

R6C3 can only be <9>

R6C7 can only be <4>

R8C3 can only be <7>

R5C9 can only be <1>

R7C7 can only be <7>

R8C5 can only be <6>

R6C1 can only be <3>

R7C3 can only be <4>

R8C7 can only be <9>