estrick: White willing exposes his king to attack by playing 25. gxf3. However, his pieces are more centralized, and Black’s queen is all alone in trying to execute an attack on the White regent. Black makes the fatal decision to advance his f-pawn two moves later in an effort to bring one of his rooks into the action and break down White’s defenses. In the process, he exposes his own king to grave danger.
With one fell swoop, White plays 30. Nb6, simultaneously threatening one of Black’s rooks directly, while also threatening a discover check that could possibly allow White’s rook to attack Black’s queen. Black accepts the loss of a rook, but sets up a mating attack that can only be stopped if White sacrifices his queen.
White willingly gives up his dame, but still has enough fire power to mount a continuous series of checks that will ultimately prove decisive, and cover all of the squares that Black’s queen would need in order to gain a half-point saving perpetual check.