     Sudoku Solution Path   Copyright © Kevin Stone R7C8 is the only square in row 7 that can be <7> R8C1 is the only square in row 8 that can be <4> R8C9 is the only square in row 8 that can be <9> R8C4 is the only square in row 8 that can be <1> R9C4 can only be <8> R9C8 is the only square in row 9 that can be <1> R1C2 is the only square in row 1 that can be <1> R1C5 is the only square in row 1 that can be <9> R2C9 is the only square in row 2 that can be <1> R5C1 is the only square in row 5 that can be <1> R9C2 is the only square in row 9 that can be <9> R3C1 is the only square in row 3 that can be <9> R3C2 is the only square in column 2 that can be <4> Squares R3C8 and R3C9 in block 3 form a simple locked pair. These 2 squares both contain the 2 possibilities <28>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.    R1C7 - removing <2> from <2345> leaving <345>    R1C8 - removing <2> from <2345> leaving <345>    R2C7 - removing <2> from <245> leaving <45> Intersection of row 7 with block 7. The value <6> only appears in one or more of squares R7C1, R7C2 and R7C3 of row 7. These squares are the ones that intersect with block 7. Thus, the other (non-intersecting) squares of block 7 cannot contain this value.    R9C3 - removing <6> from <2356> leaving <235> Intersection of column 2 with block 4. The values <27> only appears in one or more of squares R4C2, R5C2 and R6C2 of column 2. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain these values.    R4C1 - removing <2> from <235> leaving <35>    R6C1 - removing <2> from <236> leaving <36> R2C1 is the only square in column 1 that can be <2> Squares R1C3 and R2C3 in column 3 form a simple locked pair. These 2 squares both contain the 2 possibilities <56>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.    R8C3 - removing <5> from <235> leaving <23>    R9C3 - removing <5> from <235> leaving <23> Squares R8C3 and R9C3 in block 7 form a simple locked pair. These 2 squares both contain the 2 possibilities <23>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.    R7C1 - removing <3> from <356> leaving <56> R7C9 is the only square in row 7 that can be <3> R1C7 is the only square in column 7 that can be <3> R2C7 is the only square in column 7 that can be <4> R2C4 can only be <7> R1C8 can only be <5> R1C3 can only be <6> R5C4 can only be <2> R5C8 can only be <8> R1C4 can only be <4> R5C6 can only be <7> R3C8 can only be <2> R1C6 can only be <2> R2C3 can only be <5> R3C9 can only be <8> R8C6 can only be <3> R4C5 can only be <4> R8C3 can only be <2> R9C6 can only be <6> R9C5 can only be <5> R2C6 can only be <8> R2C5 can only be <6> R4C8 can only be <3> R6C5 can only be <8> R4C1 can only be <5> R6C8 can only be <4> R8C7 can only be <5> R9C3 can only be <3> R8C5 can only be <7> R9C7 can only be <2> R4C9 can only be <2> R7C1 can only be <6> R5C2 can only be <6> R4C2 can only be <7> R6C9 can only be <6> R5C9 can only be <5> R6C2 can only be <2> R7C2 can only be <5> R6C1 can only be <3> [Puzzle Code = Sudoku-20191019-Hard-119666]    