epiccuriosity: B-F5; W-E4; B-F4; W-D4
From here black is given three choices and playing F7 or G7 allows an unprotected cut.
After Black F7 or G7, W-F3; B-G3; W-F2. Now Black protects the cut with H4, but if Black had played G6 in the solution's final move, Black could descend to G2 to provide thickness on the right side of the board.
epiccuriosity: I figure G6 is the best final move over the others because if Black cuts and White wants to descend, the cutting point at G4 isn't as vulnerable.
Ivan Detkov: Could you provide the entire sequence?
B-F5; W-E4; B-F4; W-D4 From here black is given three choices and playing F7 or G7 allows an unprotected cut. After Black F7 or G7, W-F3; B-G3; W-F2. Now Black protects the cut with H4, but if Black had played G6 in the solution's final move, Black could descend to G2 to provide thickness on the right side of the board.