# Chess: Functioning on the diagonal

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The Independent Culture
BISHOPS like to develop themselves on the long diagonals - a1-h8 or h1-a8 - for two reasons. The obvious one is that as bishops function on diagonals, it seems sensible to put them on long ones.

In the English Opening, White plays 1. c4, 2. Nc3 and a later g3 and Bg2, all to control the central white squares. The Dragon Variation of the Sicilian has a black bishop on g7 bearing down on c3 and b2,and Black does all he can to enhance its influence.

The second type is less well understood. If Black plays Nf6, g6, Bg7, 0-0, d6 and e5 in the King's Indian, he is not primarily thinking of the power of the bishop on the long diagonal.

The idea here is that the pawn structure with d6 and e5 needs to expand with f5, and if White then captures on f5, you need a pawn on g6 to recapture and keep the pawn front mobile. Having weakened your black squares with g6, however, you need the bishop on g7 to avoid enemy invasion. There is a similar strategy in some Queen's Gambit lines where Black plays b6, to support a later c5, and often does not bother putting the bishop on b7.

In the following game, Black carries out his King's Indian strategy beautifully: when the centre is blocked, he frees his blocked-in bishop with h5 and Bh6, then exchanges it for its more active white counterpart.

His knight and queen invade on the weakened black squares, but then White sneaks in with his own queen and Black is killed. With 29 . . . Be8, Black prepared to meet 30. Rf1 with f6, but 30. f6+ Qxf6 31. Nf5+ is fatal. Chess can be so difficult.

Linares 1994

----------------------------------------------------------------- White: Illescas ----------------------------------------------------------------- Black: Gelfand 1 Nf3 Nf6 16 Qc2 c6 2 c4 g6 17 Bf2 Bxf2 3 Nc3 Bg7 18 Rxf2 Qd8 4 e4 d6 19 Rff1 Nf6 5 d4 0-0 20 Qb2 h4 6 Be2 e5 21 f4 h3 7 d5 a5 22 g3 Ng4 8 Bg5 h6 23 f5 Ne3 9 Bh4 Na6 24 Rf3 Qb6 10 0-0 Qe8 25 Nf1 Ng4 11 Nd2 Nh7 26 Qd2 Kg7 12 a3 Bd7 27 Qg5 Nf2+ 13 Kh1 h5 28 Rxf2 Qxf2 14 f3 Bh6 29 Ne3 Be8 15 b3 Be3 30 f6+ 1-0 -----------------------------------------------------------------