     Sudoku Solution Path   Copyright © Kevin Stone R2C2 is the only square in row 2 that can be <8> R1C5 is the only square in row 1 that can be <8> R2C8 is the only square in row 2 that can be <9> R3C6 is the only square in row 3 that can be <2> R4C2 is the only square in row 4 that can be <2> R5C9 is the only square in row 5 that can be <2> R5C5 is the only square in row 5 that can be <9> R7C4 is the only square in row 7 that can be <9> R8C1 is the only square in row 8 that can be <2> R9C9 is the only square in row 9 that can be <3> R5C1 is the only square in column 1 that can be <3> R1C2 is the only square in column 2 that can be <4> Intersection of column 9 with block 3. The value <5> only appears in one or more of squares R1C9, R2C9 and R3C9 of column 9. 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 <5> from <156> leaving <16>    R3C7 - removing <5> from <1456> leaving <146> Squares R3C5 and R7C5 in column 5 and R3C7 and R7C7 in column 7 form a Simple X-Wing pattern on possibility <4>. All other instances of this possibility in rows 3 and 7 can be removed.    R3C4 - removing <4> from <1456> leaving <156>    R7C6 - removing <4> from <46> leaving <6> R3C3 is the only square in column 3 that can be <6> R3C4 is the only square in row 3 that can be <5> R9C1 is the only square in column 1 that can be <6> R2C4 is the only square in column 4 that can be <6> R6C7 is the only square in column 7 that can be <6> R4C7 is the only square in column 7 that can be <3> Intersection of column 3 with block 4. The values <18> only appears in one or more of squares R4C3, R5C3 and R6C3 of column 3. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain these values.    R6C2 - removing <1> from <157> leaving <57> Squares R5C3 and R5C7 in row 5 and R7C3 and R7C7 in row 7 form a Simple X-Wing pattern on possibility <5>. All other instances of this possibility in columns 3 and 7 can be removed.    R4C3 - removing <5> from <158> leaving <18>    R6C3 - removing <5> from <1578> leaving <178> Squares R7C7 (XY), R7C5 (XZ) and R9C8 (YZ) form an XY-Wing pattern on <7>. All squares that are buddies of both the XZ and YZ squares cannot be <7>.    R9C5 - removing <7> from <17> leaving <1> R3C5 can only be <4> R3C7 can only be <1> R7C5 can only be <7> R2C6 can only be <1> R5C7 can only be <5> R1C8 can only be <6> R5C3 can only be <1> R7C7 can only be <4> R7C3 can only be <5> R8C9 can only be <6> R8C8 can only be <7> R1C9 can only be <5> R1C1 can only be <1> R2C9 can only be <4> R2C1 can only be <5> R4C3 can only be <8> R9C2 can only be <7> R8C2 can only be <1> R9C8 can only be <5> R6C2 can only be <5> R4C8 can only be <1> R6C3 can only be <7> R4C4 can only be <4> R6C8 can only be <8> R6C6 can only be <3> R6C4 can only be <1> R8C6 can only be <4> R8C4 can only be <3> R4C6 can only be <5> [Puzzle Code = Sudoku-20190625-SuperHard-034483]    