|Chessical: Olafsson equalises, only to blunder by overlooking a hidden threat to his back rank in time trouble.|
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He had to play either <27...Be7> or <27...Qa7> with reasonable prospects.
Olafsson is eyeing a mate on <g1>, and he calculated that the threat to his <d> pawn was mitigated by this.
Unfortunately, he did not notice that <28...Qb6> to simultaneously threaten the Bishop and mate on <g1> is refuted by <29.Bc5>. The Black Queen cannot take this impudent Bishop as her counterpart will then land on the unprotected <b8> and mate Black.
At this stage, half way through the tournament, Olafsson was the back-marker. To his credit, he fought on and in the very next round defeated Petrosian in a long game taking advantage of his opponent's poor endgame play! Petrosian vs F Olafsson, 1959