     Sudoku Solution Path   Copyright © Kevin Stone R4C2 can only be <1> R5C5 can only be <6> R6C2 can only be <4> R6C8 can only be <3> R8C4 can only be <4> R5C8 can only be <9> R2C5 can only be <5> R4C5 can only be <3> R5C2 can only be <5> R6C5 can only be <2> R4C8 can only be <6> R8C6 can only be <5> R5C4 can only be <7> R8C1 can only be <3> R8C5 can only be <9> R2C6 can only be <7> R2C4 can only be <6> R5C6 can only be <4> R2C7 can only be <9> R2C1 is the only square in row 2 that can be <1> R2C2 is the only square in row 2 that can be <3> R8C8 is the only square in row 8 that can be <1> R9C2 is the only square in row 9 that can be <9> Intersection of row 9 with block 9. The value <8> only appears in one or more of squares R9C7, R9C8 and R9C9 of row 9. These squares are the ones that intersect with block 9. Thus, the other (non-intersecting) squares of block 9 cannot contain this value.    R8C9 - removing <8> from <268> leaving <26> Squares R7C2<27>, R8C2<278> and R8C3<78> in block 7 form a comprehensive locked triplet. These 3 squares can only contain the 3 possibilities <278>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.    R7C3 - removing <7> from <457> leaving <45> Squares R1C1 and R1C8 in row 1 and R9C1 and R9C8 in row 9 form a Simple X-Wing pattern on possibility <5>. All other instances of this possibility in columns 1 and 8 can be removed.    R3C8 - removing <5> from <578> leaving <78>    R7C8 - removing <5> from <2457> leaving <247> Squares R3C2 (XYZ), R3C8 (XZ) and R1C2 (YZ) form an XYZ-Wing pattern on <7>. All squares that are buddies of all three squares cannot be <7>.    R3C3 - removing <7> from <578> leaving <58> R8C3 is the only square in column 3 that can be <7> R8C7 can only be <6> R7C2 can only be <2> R8C9 can only be <2> R8C2 can only be <8> R2C8 is the only square in row 2 that can be <2> R3C2 is the only square in row 3 that can be <6> R1C2 can only be <7> R1C9 is the only square in row 1 that can be <6> Squares R1C8 and R7C3 form a remote locked pair. <45> can be removed from any square that is common to their groups.    R7C8 - removing <4> from <47> leaving <7> R7C7 can only be <5> R3C8 can only be <8> R3C3 can only be <5> R2C9 can only be <4> R7C3 can only be <4> R3C7 can only be <7> R9C8 can only be <4> R9C1 can only be <5> R9C9 can only be <8> R1C8 can only be <5> R1C1 can only be <4> R2C3 can only be <8> [Puzzle Code = Sudoku-20191021-SuperHard-062350]    