Glossary of Chess - E

E

ECF

The English Chess Federation (ECF) is the governing chess organisation in England and is one of the federations of the FIDE. It was known as the British Chess Federation (BCF) until 2005 when it was renamed.

ECO

The Encyclopaedia of Chess Openings, a standard and comprehensive chess opening reference. Also a classification system (ECO code) for chess openings that assigns an alphanumeric code from A00 to E99 to each opening.

Edge

An edge is a small but meaningful advantage in the position against one's opponent. It is often said White has an edge in the starting position, since he moves first (see First move advantage in chess).

Elo rating system

The Elo rating system is a method for calculating the relative skill levels of chess players, named after the Hungarian Arpad Elo. Since 1970 FIDE publishes quarterly an international chess rating list using the Elo system.

En passant

("in the act of passing"; derived from French) The rule that allows a pawn that has just advanced two squares to be captured by a pawn on the same rank and adjacent file. The pawn is therefore taken as if it had only moved one space. It is only possible to take en passant on the next move.

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

The pawn on e4 is en prise

En prise

(from French; "in a position to be taken", often italicized) En prise describes a piece or pawn exposed to a material winning capture by the opponent. This is either a hanging piece, an undefended pawn, a piece attacked by a less valuable attacker, or a piece or pawn defended insufficiently. For instance, after 1.e4 Nf6 2.Nf3? leaves White's e-pawn en prise.

Endgame

The stage of the game when there are few pieces left on the board. The endgame follows the middlegame.

Endgame tablebase

A computerized database of endgames with up to seven pieces, providing perfect play for both players, and thus completely solving those endgames. (The six-piece endgames have been finished; some seven-piece endgames have been finished as of 2008.)

Epaulette mate

A checkmate position where the king is blocked on both sides by his own rooks.

Extended Position Description (EPD)

A Forsyth-Edwards Notation derivative format that contains the position on the chessboard, but not the game. It is primarily used to test chess engines.

Equalise/Equalize

To create a position where the players have equal chances of winning (referred to as "equality"). This may be either "static equality", where a draw is likely (for example, a balanced endgame) or even certain (for example, by perpetual check), or "dynamic equality", where White and Black have equal chances of winning the game. In opening theory, since White has the advantage of the first move, lines that equalize are relatively good for Black and bad for White.

Flight square

A square to which a piece can move, which allows it to escape attack. See also flight square and luft.

Exchange

1. The capture of a pair of pieces, one white and the other black, usually of the same type (i.e rook for rook, knight for knight etc.), or of bishop for knight (two pieces that are considered almost equal in value).

2. The exchange is used to refer to the advantage of a rook over a minor piece (knight or bishop). 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.

Exchange variation

This is a type of opening in which there is an early, voluntary exchange of pawns or pieces.

Exhibition

A contest of one or more games played for the purpose of public entertainment, as opposed to a match or tournament. An exhibition may pit two masters against each other, in which case chess clocks are normally used and the contest is quite serious. A simultaneous exhibition (or display) has one or more masters play many celebrity or amateur opponents at once, and is often not timed.

Expanded centre

The central sixteen squares on the board.