     Sudoku Solution Path   Copyright © Kevin Stone R5C7 can only be <1> R1C3 is the only square in row 1 that can be <2> R3C3 can only be <3> R3C7 can only be <5> R2C2 is the only square in row 2 that can be <6> R3C5 is the only square in row 3 that can be <2> R6C5 can only be <7> R6C8 can only be <3> R4C8 can only be <7> R2C9 is the only square in row 2 that can be <7> R4C4 is the only square in row 4 that can be <3> R5C5 is the only square in row 5 that can be <6> R7C1 is the only square in row 7 that can be <5> R8C8 is the only square in row 8 that can be <5> R9C9 is the only square in row 9 that can be <2> R9C7 is the only square in row 9 that can be <6> R9C3 is the only square in row 9 that can be <7> R8C1 is the only square in column 1 that can be <3> Squares R2C4 and R2C6 in row 2 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.    R2C1 - removing <14> from <1489> leaving <89>    R2C8 - removing <1> from <189> leaving <89> Intersection of column 1 with block 1. The value <8> 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.    R1C2 - removing <8> from <1489> leaving <149> Intersection of column 8 with block 3. The value <8> only appears in one or more of squares R1C8, R2C8 and R3C8 of column 8. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain this value.    R1C9 - removing <8> from <1348> leaving <134> Squares R2C1, R2C8, R1C1 and R1C8 form a Type-4 Unique Rectangle on <89>.    R1C1 - removing <9> from <1489> leaving <148>    R1C8 - removing <9> from <189> leaving <18> Squares R2C1 and R9C1 in column 1 and R2C8 and R9C8 in column 8 form a Simple X-Wing pattern on possibility <9>. All other instances of this possibility in rows 2 and 9 can be removed.    R9C2 - removing <9> from <149> leaving <14> Squares R5C6 (XY), R2C6 (XZ) and R4C5 (YZ) form an XY-Wing pattern on <1>. All squares that are buddies of both the XZ and YZ squares cannot be <1>.    R4C6 - removing <1> from <159> leaving <59> R4C5 is the only square in row 4 that can be <1> R7C5 can only be <9> R7C3 can only be <8> R7C7 can only be <3> R1C7 can only be <9> R2C8 can only be <8> R2C1 can only be <9> R1C8 can only be <1> R7C9 can only be <1> R5C3 can only be <9> R3C9 can only be <4> R8C9 can only be <8> R9C8 can only be <9> R1C2 can only be <4> R3C1 can only be <1> R1C9 can only be <3> R5C6 can only be <4> R4C2 can only be <5> R5C4 can only be <8> R2C6 can only be <1> R1C1 can only be <8> R9C2 can only be <1> R2C4 can only be <4> R8C6 can only be <2> R9C1 can only be <4> R4C6 can only be <9> R6C2 can only be <8> R6C4 can only be <2> R6C6 can only be <5> R8C4 can only be <1> R8C2 can only be <9> [Puzzle Code = Sudoku-20180613-SuperHard-274086]    