     Sudoku Solution Path   Copyright © Kevin Stone R7C6 can only be <4> R7C4 can only be <1> R7C1 can only be <7> R7C5 can only be <2> R3C4 can only be <6> R8C4 can only be <8> R7C9 can only be <3> R2C2 is the only square in row 2 that can be <2> R5C8 is the only square in row 5 that can be <2> R6C1 is the only square in row 6 that can be <2> R8C7 is the only square in row 8 that can be <7> R8C8 is the only square in row 8 that can be <5> R4C1 is the only square in column 1 that can be <5> R1C2 is the only square in column 2 that can be <9> R8C6 is the only square in column 6 that can be <6> R8C5 can only be <9> Squares R9C8 and R9C9 in row 9 form a simple locked pair. These 2 squares both contain the 2 possibilities <14>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.    R9C1 - removing <1> from <168> leaving <68>    R9C2 - removing <1> from <168> leaving <68> Squares R1C9 and R9C9 in column 9 form a simple locked pair. These 2 squares both contain the 2 possibilities <14>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.    R3C9 - removing <1> from <189> leaving <89>    R4C9 - removing <14> from <1479> leaving <79>    R6C9 - removing <4> from <478> leaving <78> Intersection of row 1 with block 3. The value <4> 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.    R2C7 - removing <4> from <148> leaving <18>    R2C8 - removing <4> from <1469> leaving <169> Intersection of column 1 with block 1. The value <1> only appears in one or more of squares R1C1, R2C1 and R3C1 of column 1. These squares are the ones that intersect with block 1. Thus, the other (non-intersecting) squares of block 1 cannot contain this value.    R2C3 - removing <1> from <168> leaving <68> Intersection of column 7 with block 6. The values <45> 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 these values.    R4C8 - removing <4> from <1349> leaving <139>    R6C8 - removing <4> from <34> leaving <3> Intersection of block 5 with row 5. The value <7> only appears in one or more of squares R5C4, R5C5 and R5C6 of block 5. These squares are the ones that intersect with row 5. Thus, the other (non-intersecting) squares of row 5 cannot contain this value.    R5C2 - removing <7> from <1378> leaving <138> Squares R9C8, R9C9, R1C8 and R1C9 form a Type-1 Unique Rectangle on <14>.    R1C8 - removing <14> from <146> leaving <6> R1C1 can only be <1> R1C9 can only be <4> R3C1 can only be <8> R9C9 can only be <1> R3C9 can only be <9> R9C1 can only be <6> R2C3 can only be <6> R3C6 can only be <3> R4C9 can only be <7> R2C8 can only be <1> R6C9 can only be <8> R9C2 can only be <8> R9C8 can only be <4> R6C3 can only be <4> R2C5 can only be <4> R2C7 can only be <8> R4C8 can only be <9> R3C5 can only be <1> R5C6 can only be <7> R5C4 can only be <4> R2C6 can only be <9> R6C7 can only be <5> R6C5 can only be <6> R2C4 can only be <7> R5C7 can only be <1> R5C2 can only be <3> R4C7 can only be <4> R6C2 can only be <7> R4C5 can only be <3> R4C3 can only be <1> R5C5 can only be <5> R5C3 can only be <8> R8C2 can only be <1> R8C3 can only be <3> R4C2 can only be <6> [Puzzle Code = Sudoku-20191021-VeryHard-024948]    