Pawn and Two: At his 30th move, Mason missed the correct continuation. He could have applied more pressure on Black's position by playing 30.Qd2. However, 30.h6 also looks attractive as the Black queen is driven into the corner. After 30...Qh8, Mason wrote: <White's attack is now thoroughly spent, and he has nothing to show for it except a position so weakened as to be incapable of withstanding the reaction which must sooner or later set in, and which a player of his opponent's style and caliber might be trusted to make the most of.>
However, opportunity was about to come calling for Mr. Mason. After 31...f6?, the White queen made her way to 32.Qf4 and 33.Qd6.
Black's best chance at this point was 33...g4, and after 34.Nd2 Rxf1+ 35.Ngxf1, White certainly has the advantage, but Black may be able to survive. Additional analysis would be needed to determine if White can win after 33...g4.
However, after 33...Rf7?, White has a clearly winning position. White could now play 34.e5! and even though Black can capture the pawn with any of three pieces, there is no escape.
If 34.e5! Rxe5 35.Rhf2 Ree7 36.Ne4. Or if 34.e5! Nxe5 35.Nxg5 Rxe1+ 36.Nxe1. A review by Fritz confirms that Black's position after 34.e5! is lost.
Mason's move 34.Rhf2?, changed his position from winning to losing in one move. The Black queen is now free to come out of her cage and Mason's grand opportunity is now only a footnote.