     Sudoku Solution Path   Copyright © Kevin Stone R3C5 can only be <5> R3C6 can only be <8> R4C4 can only be <9> R4C7 can only be <5> R5C5 can only be <7> R6C4 can only be <8> R7C5 can only be <6> R3C4 can only be <3> R6C6 can only be <2> R4C6 can only be <6> R7C4 can only be <4> R7C6 can only be <9> R4C3 can only be <7> R6C7 can only be <3> R5C3 can only be <3> R6C3 can only be <5> R5C7 can only be <4> R1C3 can only be <9> R1C7 can only be <8> R3C3 is the only square in row 3 that can be <4> R7C3 is the only square in row 7 that can be <8> R9C3 is the only square in column 3 that can be <2> Squares R2C3 and R2C7 in row 2 form a simple locked pair. These 2 squares both contain the 2 possibilities <16>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.    R2C1 - removing <1> from <135> leaving <35> Squares R2C7 and R3C8 in block 3 form a simple locked pair. These 2 squares both contain the 2 possibilities <16>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.    R3C7 - removing <16> from <1269> leaving <29> Squares R2C1 and R2C9 in row 2 and R8C1 and R8C9 in row 8 form a Simple X-Wing pattern on possibility <3>. All other instances of this possibility in columns 1 and 9 can be removed.    R7C1 - removing <3> from <1357> leaving <157>    R7C9 - removing <3> from <235> leaving <25> Squares R1C2 and R1C8 in row 1 and R9C2 and R9C8 in row 9 form a Simple X-Wing pattern on possibility <5>. All other instances of this possibility in columns 2 and 8 can be removed.    R7C2 - removing <5> from <357> leaving <37>    R7C8 - removing <5> from <135> leaving <13> Squares R2C3 and R2C7 in row 2 and R8C3 and R8C7 in row 8 form a Simple X-Wing pattern on possibility <6>. All other instances of this possibility in columns 3 and 7 can be removed.    R9C7 - removing <6> from <67> leaving <7> Squares R8C1 (XY), R3C1 (XZ) and R7C2 (YZ) form an XY-Wing pattern on <7>. All squares that are buddies of both the XZ and YZ squares cannot be <7>.    R7C1 - removing <7> from <157> leaving <15>    R3C2 - removing <7> from <67> leaving <6> R3C8 can only be <1> R9C2 can only be <5> R2C3 can only be <1> R3C1 can only be <7> R7C8 can only be <3> R2C7 can only be <6> R7C2 can only be <7> R1C8 can only be <5> R8C9 can only be <9> R3C9 can only be <2> R9C8 can only be <6> R1C2 can only be <3> R7C1 can only be <1> R8C7 can only be <1> R2C1 can only be <5> R2C9 can only be <3> R8C3 can only be <6> R3C7 can only be <9> R7C9 can only be <5> R7C7 can only be <2> R8C1 can only be <3> [Puzzle Code = Sudoku-20191117-SuperHard-334720]    