Excalibur Mirage, Руководство пользователя

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ACTIVE BISHOP vs. PASSIVE BISHOP
In this position White has a well posted bishop in the center which is free to maneuver over much of the board.
Black’s bishop, in contrast, is “biting on granite”. It has no scope because of the white pawn chain: e4, f3, g4. If
Black were to try the move ... h7-h5, to break open the prison bars, White would simply respond with h2-h3, so that
if Black exchanged pawns on g4 White could recapture with the h-pawn, thereby keeping the prison intact. So
although White’s bishop and Black’s bishop have the same material value, Black’s piece is useless to him. White
already has the unstoppable threat of Bd5-b7, picking up the a6 pawn.
1 ... Ke7-d6
2 Bd5-b7
The attempt to trap Black’s bishop by 2 h2-h4 (threatening 3 h4-h5) does not work and, in fact, would be a serious
mistake because it allows 2 ... h7-h5 under favorable circumstances White would no longer have the reply h2-h3 at his
d i s p o s a l .
2 . . . K d 6 - c 7
3 B b 7 x a 6 K c 7 - b 6
4 B a 6 - c 8 K b 6 - c 7
only safe squares for the white bishop are a6 and f5, and if the bishop returns to a6 then the black king returns to b6.
So White plays
5 Bc8-f5 Bg6xf5 6 g4xf5
And White will eventually win because of his extra pawn.
“GOOD” BISHOP vs. “BAD” BISHOP
We refer to a bishop that has plenty of scope as a good bishop and one which is restricted by its own pawns as a bad
bishop. In the above position the black bishop on c8 is bad because its own pawns at e6, d5, c6 and b7 create what is
almost a coffin, keeping the black bishop out of play for several moves.
In order to escape from behind this pawn chain Black must go through the somewhat tortuous maneuver: ... Bc8-d7,
... Bd7-e8,...f7-f6 and ... Be8-g6 (or ... Be8-h5). The problem with this plan is that it takes 4 moves to carry out and
in the meantime White will be doing something active. It is rare in chess to be given the luxury of 3 or 4 “free” moves
to carry out a plan without the opponent being able to use his reply moves very productively.
Contrast the restricted scope of the bishop on c8 with that of the “good” white bishop on e2. This bishop is ready to
come into play on the Q-side or K-side, whichever is appropriate. It is also able to switch from one side of the board
to the other very rapidly.