Lesson 11: Strong and weak squares

A square in or close to the own position is strong if it can be controlled and possibly occupied (a definition after Euwe and Reti ). It is irrelevant if the square is occupied or empty. If a square is controlled by a pawn, the opponent cannot control it (Euwe in Tijdschrift 1929 ). Therefore we consider the pawn structure as essential when we search for strong squares. At the start of the next endgame, the squares b3, b2, d3 and f4 are strong for Black. The square d5 is strong for White. The squares b5, e5 and g6 are not strong for White, because it is hardly possible to control them. So White has four strong square and White one.

[ Nb3 ! 47. Ke2 Bf4 48. Na6 Bg3 utilises the weak squares. ]

47. Nd1 Bc1 48. Ke2 !Keres has set a wonderful trap. Nc5

[ Nxb2 ? 49. Nxb2 Bxb2 50. Kd2 Bxa3 51. Kc2 Bxb4 52. cxb4 Black has won two pawns, but White has an impregnable fortress. ]

49. Kf3 g5 50. hxg5 Bxg5 51. Na2 Ke6 52. Nf2 Kf6 53. Nd1 Nd3 54. g3 Kg6 55. Kg2 Bd2 56. Kf3 Kg5 57. Ke2 Be1 58. Kf3 Bd2 59. Ke2 Be1 60. Kf3 Kf6 61. Kg2

[ Elegancy shows 61. Nb4 Nxb4 62. cxb4 Bd2 ! 63. Ke2 Bc1 ! 64. Nc3 Bxb2 65. Nxb5 Kg5 (Barcza ). ]

Kg6 ?!

[ Nc5 ! 62. Kf3 Ne6 63. g4 h4 -+ ]

62. Kf3 Kg5 63. Kg2 h4 64. gxh4+ Kf4 ?!

[Black makes progress in Bxh4 65. Kf3 Ne1+ 66. Ke3 Kg4 ]

65. h5 Kxe4 66. h6 Nf4+ 67. Kf1 Bh4 68. Nb4 Bf6 69. Ke1 Kf3 70. h7 Bg7 Strong squares for Black are b3, b2, d3, h8 and h7. Strong for White are b5 and g8. Black's great positional can be expressed in numbers this way. 71. Nc2 ?

[ 71. Nc6 ! Nd3+ 72. Kd2 The e-pawn will be stopped. It is dangerous to conquer the h-pawn, because the active knight on c6 will attack the weakness b5. ]

Nd5 ! 72. Kd2 Nf6 73. Ne1+ Ke4 74. Nf2+ Kf5 75. Ng2 Nxh7 Black has won a pawn and finishes the game quietly. 76. Ne3+ Ke6 77. Ne4 Bh6 78. Ke2 Bxe3 ! 79. Kxe3 Nf6 80. Ng5+ Kd5 81. Kf3 Nh5 82. Ne4 Nf4 83. Nf6+ Kc6 84. Ke4 Nd3 85. Ng4 Kd6 86. Nh6 Nxb2 ! 87. Nf7+ Kc5 88. Nxe5 Nd1 89. Nd7+ Kd6 90. Kd4 Nxc3 The players produced a great positional game despite the inaccuracies. Counting strong and weak squares is a useful technique. If strong squares are found near the own position, this gives information about the restriction of the opponent. Appropriate consolidation leads to strong squares in the own territory. Strong and weak pawns are found in the process. This approach gives a useful source of information to human and computer. 0-1