Lesson 10: Fortification

Petrosian, Tigran - Bertok, Mario (1961)

If a player applies fortification, a fortress is built and attackers are observed. The attacker has two narrow openings. "We will smoke them out!" he claims. Notice Black's bishop of the sad figure.

[More natural looks 44. Bd3 but the bishop remains inactive in that case. ]

Kd7 45. Bd2 Ne7 Black stops the intruders easily, although his bishop has no positional value. 46. g5+ !This a-positional move is necessary for strategic reasons. White opens a second front. Ke8 47. Ba5 Nec8 The knights are needed for the defence of the queenside. 48. Nh1 ! The plan is to play Be6 and Nf2-g4. It forces ..fxg5. fxg5 Black complies and activates his bishop.. 49. Nf2 Bf6 50. Bg4 Bd8 51. Nh3 Bf6 52. Bd2 Ne7 53. Nxg5 Bxg5 The bishop has done its duty. 54. Bxg5 Black can d o very little. One knight has to stop the penetration of white's king on the queenside. If the other one jumps to c8, exchange follows. One guard suffices at the moment. Kf7

[Interesting is Kd8 ! 55. Be6 Ke8 56. Bh4 !Zugzwang. Kd8 ?!

[ Kf8 57. Be1 Ke8 58. Ba5 ]

57. Bf7 Kd7 58. Bg5 !Zugzwang again. Kd8 59. Bxg6 ! ]

55. Bd2 ! The bishop goes to a5, before the black king can reach c7. Nec8 56. Bxc8 Nxc8 Cooperation between the strong bishop and active king will decide the endgame quickly. 57. Bg5 ! Consolidation prevents a counteraction on the kingside. Nb6 58. Bd8 Nc8 59. Ka4 Ke8 60. Bg5 Kd7 61. Kb5 Kc7 62. Ka6 Nb6 This allows an elegant move. 63. Bd8+ !The exchanges have led to a won pawn ending. 1-0