Imminent disaster

Mistakes in chess come in pairs. Last month, and not for the first time, that nugget of wisdom thumped me on the nose. Representing England at the Olympiad in Budapest, my game against Luca Moroni was proceeding rather pleasantly. It was clear the Italian grandmaster had underestimated my sacrifice of rook for bishop in the middlegame, and I was about to recover my material investment with interest. Alas, my return was diminished by an elementary tactical oversight, missing the move 25 Na4xb6 (see first diagram). No matter – I was still a pawn to the good. I moved my rook which was under attack, and he responded in the obvious way. One minor hiccup need not derail an otherwise agreeable game. Oblivious to any danger, my crude blunder on the very next move allowed 27 Nb3xa5. Another pawn gone, and what was worse, the frenzied cavalry were about to sack the remains of my position.