At the traditional Hastings tournament of 1974/75, Rafael Vaganian has White against Albin Planinc. The Slovenian grandmaster of the Yugoslav school had already attracted attention by sharing first place with Petrosian in Amsterdam in 1973. This encounter comes from round five of the winter tournament in England.
After 20.Qxa8 Qd6+ 21.Kc1, Planinc plays the unusual 21...Na1. The knight in the corner supports a trap, but the move does not yet force a win. Vaganian continues with 22.Qxb7 and resigns after 22...Qc7+. Taking the queen with 23.Qxc7 would allow 23...Nb3#. Those last two half-moves explain the idea; they were not played in the game.