Prophylaxis (chess)

series of moves done by a player to prevent their opponent from taking some action

Prophylaxis is a term in chess, as well as being a general idea. It was introduced by the grandmaster Aaron Nimzovich in his book My system in the 1920s.[1] The term refers to actions taken by a player to anticipate and thwart the opponent's plans, and moves of these type are often called prophylactic moves.[2]

Pirc Defence: 1.e4 d6
abcdefgh
8
a8 black rook
c8 black bishop
d8 black queen
f8 black rook
g8 black king
a7 black pawn
b7 black pawn
f7 black pawn
g7 black bishop
h7 black pawn
a6 black knight
c6 black pawn
d6 black pawn
f6 black knight
g6 black pawn
e5 black pawn
d4 white pawn
e4 white pawn
c3 white knight
g3 white pawn
a2 white pawn
b2 white pawn
c2 white pawn
e2 white knight
f2 white pawn
g2 white bishop
h2 white pawn
a1 white rook
c1 white bishop
d1 white queen
e1 white rook
g1 white king
8
77
66
55
44
33
22
11
abcdefgh
White's next move 9.h3 denies the square g4 to the black B & N, and prepares the developing move 10.Be3

Example #1

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One simple example of a prophylactic move is when a player moves a rook's pawn forward h3 or h6 to prevent a back rank mate, and at the same time prevent an enemy bishop or knight from occupying g4 or g5. In the example, mate was not an issue, but h3 was still played by world champion Karpov. Then he could develop his QB to the best place on e3.

abcdefgh
8
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8
77
66
55
44
33
22
11
abcdefgh
Black to play

Example #2

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Other examples are so subtle that club players would probably never think about them as possible moves. In the second example Nimzovich himself was playing black. In general, he wanted to turn his KP into a passed pawn by advancing it. However, the direct ...e5 does not work well, because the black king gets pushed back:

1.... e5
2.fxe5 fxe5
3.g4+ hxg4
4.hxg4+ Ke6
5.Rd6+ and the black king is kept out of play.

Nimzovich found another way to go:

1.... Rf8! and now after
2.Be1 g5! is best because
3.fxg5 fxg5
4.g4+ hxg4
5.hxg4+ Ke5+ wins the white rook.

To avoid this, White himself needs to play a prophylactic move, namely:

2.Kg1. This would prevent the discovered check on the f-file. Nimzovich's opponent did not find this, and Black went on to win the game. The game was won and lost on the players' relative awareness of prophylactic moves.[3]

References

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  1. Nimzowitsch, Aron [1927] 1987. My system. B.T Batsford Ltd. ISBN 9789197600538
  2. Watson, John 1998. Secrets of modern chess strategy: advances since Nimzowitsch. Gambit, London. Chapter 9, p211. ISBN 1-901983-07-2
  3. Dvortevsky, Mark 1996. Prophylactic thinking. In Dvortevsky M & Yusupov A. Positional play. London: Batsford. ISBN 0-7134-7879-9