Beware of superior positions - they can very easily let you down, as this game from the world junior championship testifies. Actually, this position from the game Gershon-Morozevic is finely balanced. White's bishop is more active, his pawn on f5 has a cramping effect, and his rook commands the open file. But Black's knight has a fine square on e5, and his king is nearer the centre. White, however, saw a tempting combination, and that was the start of his downfall.

White began 1.Ne4, threatening a fork on d6. He must have thought that Black had fallen into his trap when he replied 1...Bf6, for he then played 2.Rd6. White threatens both Rxf6+ and Rxa6, and 2...Bxd6 loses a piece after 3.Nxd6+.

Morozevic continued calmly with 2...Be7 and after 3.Rxa6 grabbed the open file with 3...Rd7. White has won a pawn, but all is far from well with his position. The threat is gxf5 followed by Rd2, when White cannot cope with the threat to his bishop while preventing a back-rank mate.

White tried to give his king an escape with 4.h3 when there followed 4...gxf5 5.Ng3 f4 6.Nf5 Rd2 7.Be4 Bc5. Now as long as White's knight guards g3, Black has no immediate threat, but White is desperately short of moves. He cannot play, for example, 8.Ra5 because of 8...Rd1+ 9.Kh2 Bg1+ 10.Kh1 Bb6+. If White does nothing, Black can calmly play h5 and h4 to complete his mating net.

The game continued 8.Nh6+ Ke7 9.h4 Bf2 10.Kh2 Kd7 11.Bf5+ Kc7 12.Ng4 (12.Rxf6 loses to 12...Bg3+ 13.Kh3 Rd1) 12...Bg3+ 13.Kh3 Rd1! 14.Nxe5 h5! 15.Rc6+ Kb8 and White resigned. He cannot prevent Rh1 mate.

Moral: think carefully before winning a pawn if it means losing the initiative.