The ''Encyclopaedia of Chess Openings'' () is a reference work describing the state of opening theory in

chess Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to dist ...

, originally published in five volumes from 1974 to 1979 by the

Serbia Serbia (, ; Serbian: , , ), officially the Republic of Serbia (Serbian: , , ), is a landlocked country in Southeastern and Central Europe, situated at the crossroads of the Pannonian Basin and the Balkans. It shares land borders with Hung ...

n company Šahovski Informator ( Chess Informant). It is currently undergoing its fifth edition. ''ECO'' may also refer to the opening classification system used by the encyclopedia.

Overview

Both ''ECO'' and '' Chess Informant'' are published by the Belgrade-based company Šahovski Informator. The moves are taken from thousands of master games and from published analysis in ''Informant'' and compiled by the editors, most of whom are grandmasters, who select the lines which they consider most relevant or critical. The chief editor since the first edition has been Aleksandar Matanović. The openings are provided in an ''ECO'' table that concisely presents the opening lines considered most critical by the editors. ''ECO'' covers the openings in more detail than rival single volume publications such as ''

Modern Chess Openings ''Modern Chess Openings'' (usually called ) is a reference book on chess openings, first published in 1911 by the British players Richard Clewin Griffith (1872–1955) and John Herbert White (1880–1920). The fifteenth edition was published in ...

'' and '' Nunn's Chess Openings'', but in less detail than specialized opening books. The books are intended for an international audience and contain only a small amount of text, which is in several languages. The bulk of the content consists of diagrams of positions and chess moves, annotated with

symbols A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different co ...

, many of them developed by Chess Informant. Chess Informant pioneered the use of Figurine Algebraic Notation to avoid the use of initials for the names of the pieces, which vary between languages. Instead of the traditional names for the openings, ''ECO'' has developed a coding system that has also been adopted by other chess publications. There are five main categories, "A" to "E", corresponding to the five volumes of the earlier editions, each of which is further subdivided into 100 subcategories, for a total of 500 codes. The term "''ECO''" is often used as a shorthand for this coding system. ''ECO'' code is a registered trademark of Chess Informant.

Openings covered

Volume A: Flank openings

English Opening The English Opening is a chess opening that begins with the move: :1. c4 A flank opening, it is the fourth most popular and, according to various databases, one of the four most successful of White's twenty possible first moves. White begins t ...

* Benoni Defence *

Dutch Defence The Dutch Defence is a chess opening characterised by the moves: :1. d4 f5 Black's 1...f5 stakes a claim to the e4-square and envisions an attack in the middlegame on White's ; however, it also weakens Black's kingside to an extent (especial ...

Réti Opening The Réti Opening is a hypermodern chess opening whose "traditional" or "classic method" begins with the moves: :1. Nf3 d5 :2. c4 White attacks Black's pawn from the , which may occasion 2...dxc4. White may couple this plan with a kingsid ...

* Benko Gambit * Old Indian Defence *

Bird's Opening Bird's Opening (or the Dutch Attack) is a chess opening characterised by the move: :1. f4 Bird's is a standard flank opening. White's strategic ideas involve control of the e5-square, offering good attacking chances at the expense of slightly ...

* Anti- Indian systems ( Trompowsky Attack, Torre Attack, Richter–Veresov Attack) * Irregular openings, etc.

Volume B: Semi-Open Games other than the French Defence

Sicilian Defence The Sicilian Defence is a chess opening that begins with the following moves: :1. e4 c5 The Sicilian is the most popular and best-scoring response to White's first move 1.e4. Opening 1.d4 is a statistically more successful opening for White be ...

* Caro-Kann Defence * Pirc Defence *

Alekhine's Defence The Alekhine's Defence is a chess opening that begins with the moves: :1. e4 Nf6 Black tempts White's pawns forward to form a broad , with plans to undermine and attack the white structure later in the spirit of hypermodern defence. White's i ...

* Modern Defence * Scandinavian Defence, etc.

Volume C:
Open Game An Open Game (or Double King's Pawn Opening) is a chess opening that begins with the following moves: :1. e4 e5 White has moved the king's pawn two squares and Black has replied in kind. The result is an Open Game. Other responses to 1.e4 are te ...
s and the French Defence

Ruy Lopez The Ruy Lopez (; ), also called the Spanish Opening or Spanish Game, is a chess opening characterised by the moves: :1. e4 e5 :2. Nf3 Nc6 :3. Bb5 The Ruy Lopez is named after 16th-century Spanish priest Ruy López de Segura. It is one ...

French Defence The French Defence is a chess opening characterised by the moves: :1. e4 e6 This is most commonly followed by 2.d4 d5, with Black intending ...c5 soon after, attacking White's and gaining on the . The French has a reputation for solidity ...

Petrov's Defence Petrov's Defence or the Petrov Defence (also called Petroff Defence, Petrov's Game, Russian Defence, or Russian Game – russian: Русская партия) is a chess opening characterised by the following moves: :1. e4 e5 :2. Nf3 Nf6 Tho ...

* Vienna Game * Centre Game *

King's Gambit The King's Gambit is a chess opening that begins with the moves: :1. e4 e5 :2. f4 White offers a pawn to divert the black e-pawn. If Black accepts the gambit, White has two main plans. The first is to play d4 and Bxf4, regaining the gambit ...

Philidor Defence The Philidor Defence (or Philidor's Defence) is a chess opening characterised by the moves: :1. e4 e5 :2. Nf3 d6 The opening is named after the famous 18th-century player François-André Danican Philidor, who advocated it as an alternative ...

* Italian (

Giuoco Piano The Giuoco Piano ( Italian: "Quiet Game"; ), also called the Italian Opening, is a chess opening beginning with the moves: :1. e4 e5 :2. Nf3 Nc6 :3. Bc4 Bc5 "White aims to develop quickly – but so does Black. White can construct a pawn ce ...

Evans Gambit The Evans Gambit is a chess opening characterised by the moves: :1. e4 e5 :2. Nf3 Nc6 :3. Bc4 Bc5 :4. b4 The Evans Gambit is an aggressive line of the Giuoco Piano. White offers a pawn to divert the black bishop on c5. If Black accepts, ...

, Hungarian Defence, and Two Knights) * Scotch Game *

Four Knights Game The Four Knights Game is a chess opening that begins with the moves: :1. e4 e5 :2. Nf3 Nc6 :3. Nc3 Nf6 This is the most common sequence, but the knights may in any order to reach the same position. The opening is fairly popular with begi ...

, etc. * King's Pawn Opening, etc. (covers unusual/rare 1. e4 openings such as the Elephant Gambit and

Ponziani Opening The Ponziani Opening is a chess opening that begins with the moves: :1. e4 e5 :2. Nf3 Nc6 :3. c3 It is one of the oldest chess openings, having been discussed in the literature by 1497. It was advocated by Howard Staunton, generally consi ...

Volume D: Closed Games and Semi-Closed Games

:(''including Grünfeld Defence but not other Indian Defenses'') *

Queen's Gambit The Queen's Gambit is the chess opening that starts with the moves: :1. d4 d5 :2. c4 It is one of the oldest openings and is still commonly played today. It is traditionally described as a '' gambit'' because White appears to sacrifice the ...

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** Declined (

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, Orthodox, Tarrasch, Tartakower,

Albin Countergambit The Albin Countergambit is a chess opening that begins with the moves: :1. d4 d5 :2. c4 e5 and the usual continuation is: :3. dxe5 d4 The opening is an uncommon defense to the Queen's Gambit. In exchange for the gambit pawn, Black has a ...

, etc.) *

Grünfeld Defence The Grünfeld Defence is a chess opening characterised by the moves: :1. d4 Nf6 :2. c4 g6 :3. Nc3 d5 Black offers White the possibility of 4.cxd5, which may be followed by 4...Nxd5 and 5.e4, giving White an imposing central pawn duo. If Whi ...

* Queen's Pawn Game, etc.

Volume E: Indian Defences

:(''other than Grünfeld Defence and Old Indian Defence'') *

Nimzo-Indian Defence The Nimzo-Indian Defence is a chess opening characterised by the moves: :1. d4 Nf6 :2. c4 e6 :3. Nc3 Bb4 Other move orders, such as 1.c4 e6 2.Nc3 Nf6 3.d4 Bb4, are also feasible. In the ''Encyclopaedia of Chess Openings'', the Nimzo-Indian ...

* Queen's Indian Defence * King's Indian Defence *

Catalan Opening The Catalan Opening is a chess opening where White plays d4 and c4 and fianchettoes the white bishop on g2. A common opening sequence is 1.d4 Nf6 2.c4 e6 3.g3, although various other openings can transpose into the Catalan. The '' Encyclopaedia ...

Bogo-Indian Defence The Bogo-Indian Defense is a chess opening characterised by the moves: :1. d4 Nf6 :2. c4 e6 :3. Nf3 Bb4+ The position arising after 1.d4 Nf6 2.c4 e6 is common. The traditional move for White here is 3.Nc3, threatening to set up a big pawn c ...

, etc.

Main ''ECO'' codes

A

* White first moves other than 1.e4, 1.d4 (A00–A39) * 1.d4 without 1...d5, 1...Nf6 or 1...f5: Atypical replies to 1.d4 (A40–A44) * 1.d4 Nf6 without 2.c4: Atypical replies to 1...Nf6 (A45–A49) * 1.d4 Nf6 2.c4 without 2...e6, 2...g6: Atypical Indian systems (A50–A79) * 1.d4 f5:

(A80–A99)

B

* 1.e4 without 1...c6, 1...c5, 1...e6, 1...e5 (B00–B09) * 1.e4 c6:

Caro–Kann Defence The Caro–Kann Defence is a chess opening characterised by the moves: :1. e4 c6 The Caro–Kann is a common defence against the King's Pawn Opening. It is classified as a Semi-Open Game, like the Sicilian Defence and French Defence, although ...

(B10–B19) * 1.e4 c5:

(B20–B99)

C

* 1.e4 e6:

(C00–C19) * 1.e4 e5: Double King Pawn games (C20–C99)

D

* 1.d4 d5: Double Queen Pawn games (D00–D69) * 1.d4 Nf6 2.c4 g6 with 3...d5:

(D70–D99)

E

* 1.d4 Nf6 2.c4 e6: Indian systems with ...e6 (E00–E59) * 1.d4 Nf6 2.c4 g6 without 3...d5: Indian systems with ...g6 (except Grünfeld) (E60–E99)

First edition

The first edition was published in the following years: * Volume A: 1979 * Volume B: 1975 * Volume C: 1974 * Volume D: 1976 * Volume E: 1978

Second edition

The second edition was published in the following years: * Volume A: 1996 * Volume B: 1984 * Volume C: 1981 * Volume D: 1987 * Volume E: 1991

Third edition

The third edition was published in the following years: * Volume A: 1999 * Volume B: 1997 * Volume C: 1997 * Volume D: 1998 * Volume E: 1998

Fourth edition

The fourth edition was published in the following years: * Volume A: 2001 * Volume B: 2002 * Volume C: 2000 * Volume D: 2004 * Volume E: 2008

Fifth edition

The fifth edition was published in the following years: * Volume C: 2006 * Volume B part 1 CO codes: B00–B49 2020 * Volume B part 2 CO codes: B50-B99 2021

References

* * *

External links

* Publisher's site * ''ECO'' codes with names {{Chess, state=collapsed *Encyclopedia of Chess Openings Chess books Chess in Serbia 20th-century encyclopedias