It must have pained Fischer to play Kh2. This lets the initiative go back over to Black who
draws a bead on the King with his black-squared Bishop. White's 22nd move is generally
regarded as too passive. White is uncomfortable with the Black Knight at f4 and exchanges
his dark-squared Bishop for it. The advanced center pawns look ominous but the sequence
allows White to grab the e pawn.
21. Kh2 Bd6
22. Bb3 Nf4
23. Bxf4 exf4