Many years ago I reached this position as Black against a young expert. I had just managed to trade off two of my opponent's active pieces, which was helpful because sometime earlier I had played the mysterious weakening move ...g7-g6, leaving my king in a very draughty position. But now I was the one with the active pieces.
Naturally enough I was starting to think about how to get something going against his king. Queen to the long diagonal looks crunchy, but there is the small problem of his queen and knight controlling key squares. Deflect his queen perhaps? How about taking the rook pawn with my rook? Queen takes rook is met by queen to c6 check – a killer. But he can take with his rook. I get a couple of checks with my queen and knight, but what then? Suddenly it all became clear:
My opponent gave a small gasp of surprise, then put his head in his hands and began to stare intently at the position. I didn't feel like staying at the board, so I got up and wandered around the tournament hall, leaving him to think it over. Five minutes went by, then ten, then fifteen. Finally after twenty minutes my opponent turned and looked at me across the hall and smiled. Then he reached over and stopped the clocks.
Because 2.Qxa3 Qc6+ loses immediately, White must play 2.Rxa3. But then comes 2...Qc1+ 3.Kg2 Qg1+ 4.Kf3 Nd4+ and if 5.Kf4 then 5...g5 is mate. Instead of 5.Kf4 White must play 5.Qxd4, but after 5...Qxd4 Black faces only a technical task in order to notch the point.
In our next encounter my young opponent won a pawn with forceful play and then ground me down in a long bishop ending.