Although there was still a lot of play ahead, I felt that white's position was losing to black's and I needed some good counterplay before black's A & B pawns became a real problem. Post game analysis with Fritz9 also assessed the position as good for black. So, I played 27. g5 to create some targets and counterplay. In fact, Fritz9 recommended this move for white. Black, already a pawn up and in the throes of a strong queenside attack, could have maintained the pressure by simply playing 27... Qc4 or 27...h5. But, no. He had to grab the pawn! This pawn-grab initiated a series of forced moves that led to his demise. After 27... hg5?, the attack commenced with 28. Rh3 ( threatening mate on h7 ) g6 ( forced ) 29. Qc3 ( threatening mate on h8 ) f6 ( forced and covering the diagonal ) and then the very lovely sacrifice 30. Rh8+ and black resigned with a mate in two coming.