ChessWorld Glossary

ChessWorld Hitchhiker's Guide to Chess

Scope: This glossary does not intend to cover player names, opening names, or Composition terms. The Glossary aims to relate the terms to ChessWorld where possible when giving examples.
If you have contributions, corrections or questions, please post them to the Chess Forum for discussion.
There is a dedicated Chess Openings Glossary

Glossary Course Modules with Game Examples

Glossary Course Modules with Tactical Puzzle Examples

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E

ECO
Encyclopedia of Chess Openings, the standard multi-volume reference work on opening strategy.

The are five volumes covering in total 500 different ECO codes (A00-A99, B00-B99, C00-C99, D00-D99, E00-E99) as follows:

Volume A: All non standard openings including a few which begin 1.d4
Volume B: Openings beginning with 1.e4 but *NOT* where black replies e5 or e6 i.e. NOT 1.e4 e5 and NOT 1.e4 e6
Volume C: 1.e4 e5 and 1.e4 e6
Volume D: 1.d4 d5
Volume E: Most other openings beginning with 1.d4

This method of classifying Openings has become the most popular as of 2006. It has contributions from many leading Grandmasters, and often the ECO tag is part of a PGN game score as a way of quickly identifying the Opening of the game.

You can find example games of ECO codes by clicking this link.

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En Passant
(In passing)

Enpassant is a a special pawn capture which is illustrated on this page.
There is also a step by step illustration to be found on this page

From these two illustrations, you should have noted that to do an "enpassant" pawn capture, you need the following to be true:-

1) You have a pawn on the 5th rank (i.e. just inside your opponents territory)
2) The opponents pawn has moved TWO squares from its original position
3) The opponents pawn needs to be either one square to the left or one square to the right of your pawn.
4) When the opponents pawn moves TWO squares (in one jump), you can only take advantage of the Enpassant move on the *very next move* after your opponent moved their pawn two squares forward. You cannot play the special Enpassant move later on in the game after playing something else.

For another example, see the diagram below:-

Analyse position

White now plays the move d2-d4:

Analyse position

Black now can play cxd3 taking the 'd' pawn with the special "en passant" pawn capture :-

Analyse position

You can see that the black pawn has moved diagonally as though it has captured a pawn on d3. Except it is the pawn on d4 which has been "captured".

Note that in this example :

1) Black has a pawn on the 5th rank - the c4 pawn in this example
2) The opponents pawn is the d pawn attempting to go TWO squares up from d2 to d4
3) When White plays d2-d4 the d4 pawn is one square to the right of the c pawn.
4) Black has immediately taken advantage of the Enpassant option. Immediately after White played d2-d4, Black did the special Enpassant. If another move was played by Black instead, the Enpassant option would be lost.

So ALL the conditions were successfully met for enpassant. Black was able to capture White's d pawn with the move c4xd3 (enpassant).

Why is there a special En-passant move?!

Pawns could originally only move forward one square at a time and the ability to move two on a pawn's first move was introduced to speed up the game. Therefore when a pawn moves two squares so as to avoid capture by a pawn then the opponent, in reply, may capture it as though it had only moved one square.

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En prise
When a piece can be captured for "free" (at least in an immediate material sense) because it is unprotected by any of the opponents pieces or pawns.

However sometimes the opponent can leave pawns "en prise" but the piece or pawn might be "poisoned". E.g. take the following very sharp position which can come from the Sicilian Najdorf "Poisoned pawn" variation:-

Analyse position

White has just played the Queen from d1 to d2. Now the b2 pawn is technically "en prise" - i.e. it is :-

1) Undefended by anything else
2) Attacked by one of the opponents pieces, i.e. the Queen on b6

However, although Black could take the pawn on b2, White would gain some compensation in terms of extra speed of development etc. So strictly the pawn on b2 is not entirely "free". It is only "free" in an immediate material gain sense, for Black to gain material without an immediate material penalty of White being able to recapture in some way.

In the above position, the b2 pawn is the only piece or pawn which is technically "en prise", because for example the White knight on d4 is protected by the Queen on d2. So the d4 pawn is not technically "en prise". It is only the pawn on b2 which is "en prise".

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Endgame
The last stages of a game, involving few pieces, usually without queens for either side.

An example Endgame is shown below:-

Analyse position

Majnu has done some great endgame videos

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Endings
Another name for the Endgame.

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Exchange
The capture of pieces belonging to both sides during the course of a few moves. (See also Winning the Exchange).

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Exchange Sacrifice
An "Exchange Sacrifice" is when one intentionally gives up a rook in exchange for a minor piece in order to achieve a specific goal.

For example:

1) Sacrificing a Rook for knight + 0 to 2 pawns
2) Sacrificing a Rook for a bishop + 0 to 2 pawns

The player who captures a rook while losing a minor piece is said to have won the exchange, and the opponent is said to have lost the exchange. An exchange sacrifice is giving up a rook for a minor piece.

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