ECO Volume A · A00–A99

Volume A — Flank & Uncommon Openings

Everything that starts away from the classical centre: the English, Réti, Bird's, plus the Benoni, Benko, Dutch and other fighting defences to 1.d4. 1.c4, 1.Nf3, 1.f4 & the sharp d4 defences.

English Opening

A10

The English Opening is the thinking player's 1.c4 — an opening of patience and geometry. Instead of fighting for the centre with pawns, White builds a flexible bind and strikes later, exactly where Black is weakest. It transposes into reversed Sicilians, Catalan structures and hedgehogs, making it a lifetime repertoire in one move.

For WhiteIntermediate

English Opening

A10

1.c4 is chess in a dinner jacket: long-term plans, flexible structures and queenside space-grabbing, beloved by Botvinnik, Kasparov and Carlsen.

For WhiteIntermediate

English Opening: Reversed Sicilian

A20

1...e5 turns the game into a Sicilian with colours reversed — White is a tempo up in the attacker's dream position.

For WhiteIntermediate

Flank Opening Deep Lines: English, ...Nf6 Setup

A10

The Anglo-Indian: the most popular English defence.

For WhiteBeginner-friendly

Indian Game

A50

The gateway to the Indian defences: after 1.d4 Nf6 2.c4 Black chooses Nimzo, Budapest, Bogo, Old Indian and more.

For WhiteBeginner-friendly

Queen's Pawn Game

A40

The catch-all for 1.d4 lines without an early c4 — including the Englund Gambit 1.d4 e5!? and Black's many offbeat setups.

For WhiteBeginner-friendly

Benoni Defence

A56

The Modern Benoni: Black accepts a cramped position and fights back with the g6-bishop, piece pressure and queenside play.

For BlackAdvanced

Benoni Defence, Modern Variation

A60

The Modern Benoni main move order: maximum tension, the g7 bishop, and the fight over e4 and d5.

For BlackAdvanced

Benoni, Classical with Nf3

A70

The Classical Benoni: pure piece play — Bd3/Re1 plans versus ...c5-c4 and ...b5 queenside explosions.

For BlackAdvanced

English Opening, Anglo-Indian Defence

A15

The Anglo-Indian (1.c4 Nf6) heads for King's-Indian and Réti-style battles where move orders decide who gets the structure they want.

For BlackIntermediate

English Opening, King's English

A20

1...e5 turns the game into a reversed Sicilian — the same attacking patterns with White a tempo up.

For WhiteIntermediate

English Opening: Hedgehog System

A30

Black's spiky a6-b6-d6-e6 constellation waits like a hedgehog: cute until you touch it.

For WhiteAdvanced

English Opening: Keres Variation

A23

The main-line King's English: immediate queenside expansion against the reversed-Dragon structure.

For WhiteIntermediate

English Opening: Mikenas-Carls Variation

A18

The sharpest English line: 3.e4 grabs the centre and forces immediate structural decisions.

For WhiteAdvanced

English Opening: Symmetrical Main Line

A39

The theoretical heart of the Symmetrical English — sharp piece play around d5 and the dark squares.

For WhiteAdvanced

English Opening: Symmetrical Variation

A30

Black mirrors everything, reaching double-fianchetto structures where the first concrete mistake decides.

For WhiteIntermediate

English, Closed System

A25

The Closed English: a slow squeeze with f4, h3 and Be3 pressure against Black's compact kingside.

For WhiteIntermediate

English, Mikenas-Carls Variation

A18

The sharpest English line: 3.e4 grabs the centre and forces immediate structural decisions.

For WhiteAdvanced

English, Symmetrical Variation

A30

1...c5 mirrors White's setup — Hedgehog structures, Botvinnik systems and maneuvering duels where every tempo counts.

For WhiteIntermediate

English, Symmetrical, Main Line

A38

The main-line Symmetrical: full development first, then the decisive d4/...d5 central clashes.

For WhiteIntermediate

English, Symmetrical, Main Line with d4

A39

The theoretical heart of the Symmetrical English — sharp piece play around d5 and the dark squares.

For WhiteAdvanced

Flank Opening Deep Lines

A10

The deep-line archive of Volume A: named sub-variations of the English, Réti, Bird's, Dutch, Benoni and Benko — the lines that decide real games once both players know the first ten moves.

For WhiteIntermediate

Flank Opening Deep Lines: Benoni, Classical Setup

A65

The classical setup: the Modern Benoni's main structure.

For WhiteAdvanced

Flank Opening Deep Lines: Benoni, Modern ...g6 Setup

A65

The g6 setup: the Modern Benoni's fianchetto structure.

For WhiteAdvanced

Flank Opening Deep Lines: English, ...c5 Setup

A30

The Symmetrical: the mirror defence to 1.c4.

For WhiteIntermediate

Flank Opening Deep Lines: English, ...e5 Setup

A20

The King's English: the reversed-Sicilian defence.

For WhiteIntermediate

Flank Opening Deep Lines: English, King's English 4.d44.g3 Setup

A28

The g3 fianchetto setup: the King's English's main treatment.

For WhiteIntermediate

Flank Opening Deep Lines: English, Symmetrical Hedgehog

A30

The Hedgehog core: the a6-b6-d6-e6 chain versus the c4/d4 clamp.

For WhiteAdvanced

Flank Opening Deep Lines: Réti Setup

A04

The pure Réti: the most flexible first move in chess.

For WhiteBeginner-friendly

Flank Opening Deep Lines: Réti, ...Nf6 Setup

A05

The ...Nf6 setup: the most popular Réti defence.

For WhiteBeginner-friendly

Modern Benoni

A56

The Modern Benoni is the sharpest reply to 1.d4: Black accepts a cramped, locked structure and fights back with the g7-bishop, piece pressure and queenside play. Tal, Kasparov and every romantic since have used it to turn White's space into overextension.

For BlackAdvanced

Modern Benoni: Classical Variation

A70

The classical main tabiya: piece pressure and timing battles around e4 and b5.

For BlackAdvanced

Réti Opening

A04

Richard Réti's hypermodern masterpiece: instead of occupying the centre, White attacks it with pieces from the flanks. The bishop on g2 stares at d5 while pawns wait — then strikes exactly when Black overextends.

For WhiteIntermediate

Réti Opening

A04

The hypermodern masterpiece: White attacks the centre with pieces from a distance, leading to rich manoeuvring battles.

For WhiteIntermediate

Réti Opening, 1...Nf6

A05

With 1...Nf6 Black keeps maximum flexibility — the game can become a Queen's Indian, Catalan or pure Réti.

For WhiteIntermediate

Benko Gambit

A57

The Benko (Volga) Gambit is the purest example of positional compensation in chess: Black trades a pawn — often two — for permanent pressure down the a- and b-files and a monster bishop on g7. The compensation never fades; it just changes form.

For BlackIntermediate

Benko Gambit

A57

Black trades a pawn — often two — for permanent a/b-file pressure and the monster g7 bishop: compensation made visible.

For BlackIntermediate

Benko Gambit Accepted

A58

The full Benko structure: open files, dark-square strategy and endings where Black's pieces outfight White's pawns.

For BlackIntermediate

Benko Gambit, 7.e4 Main Line

A59

The classical main line: White grabs the centre, Black's bishop stares down the long diagonal — sharp and principled.

For BlackAdvanced

Benko Gambit: 5.e3 Setup

A57

The immediate acceptance — the cleanest theory path into Benko structures.

For BlackIntermediate

Benko Gambit: Benko Accepted

A58

The full Benko structure: open files, dark-square strategy and endgames where pieces outfight pawns.

For BlackIntermediate

Benko Gambit: King's Walk Line

A59

The king retreats to g1 — White's best try to tuck the monarch away from the long diagonal.

For BlackAdvanced

Benko Gambit: Main Line 7.e4

A59

The classical main line: White grabs the centre, Black's bishop stares down the diagonal.

For BlackAdvanced

Benoni, 6.e4

A65

The classical Benoni formation: White takes the big centre, Black strikes back with ...g6/...Bg7 and ...Re8.

For BlackAdvanced

Benoni, Classical without 9.O-O

A72

White's flexible 9.h3 setup keeps Re1 and Nd2 options open against Black's queenside counterplay.

For BlackAdvanced

Benoni, Classical, 10...a6

A74

Black's ...a6/...b5 expansion meets White's a4 clamp — the structural Cold War of the Classical Benoni.

For BlackAdvanced

Benoni, Classical, 8.Bg5

A71

The early Bg5 pin targets e7 pressure and g4 tricks — a sharp sideline with real venom.

For BlackAdvanced

Benoni, Classical, 9...Re8

A76

The ...Re8/...Nbd7 setup readies ...b5 breaks — the most principled classical battleground.

For BlackAdvanced

Benoni, Classical, 9.O-O

A73

The main Classical tabiya: Nd2-c4-e3 manoeuvres against ...b5/...a6 timing battles.

For BlackAdvanced

Benoni, Fianchetto System

A61

White's fianchetto answers Black's — a slower Benoni where the dark-square battle replaces the pawn storms.

For BlackIntermediate

Benoni, Fianchetto with 8...O-O

A62

The smooth Fianchetto Benoni: Black's ...Re8 and ...a6/...b5 queenside play against White's central clamp.

For BlackIntermediate

Benoni, Four Pawns Attack

A68

White's maximalist centre: four pawns and an e5 break against Black's piece pressure and timing counters.

For BlackAdvanced

Benoni, Four Pawns, Main Line

A69

The tactical resolution of the Four Pawns: knights dance on the dark squares while the centre burns.

For BlackAdvanced

Benoni, Pawn Storm

A66

The e4-f4 wedge sets up g4-g5 pawn storms — brutal attacking chess on both wings.

For BlackAdvanced

Benoni, Taimanov Variation

A67

Taimanov's Bb5+ check and e5 break — one of the sharpest, most analyzed Benoni battlegrounds.

For BlackAdvanced

Budapest Gambit

A51

The Budapest Gambit is the classic club weapon against 1.d4: an immediate pawn sacrifice for open lines, quick development and a web of traps. Black gets real activity for real risk — and famous smothered-mate finishes when White yawns.

For BlackBeginner-friendly

Budapest Gambit

A51

Black's enterprising pawn sac rips open lines and sets instant traps — the classic club weapon against 1.d4.

For BlackBeginner-friendly

Budapest Gambit, Rubinstein Variation

A52

Rubinstein's refined main line: Black regains the pawn with piece activity and keeps the initiative brewing.

For BlackIntermediate

Budapest Gambit: Adler Variation

A51

The solid knight-development answer — heading for the Rubinstein structures.

For BlackBeginner-friendly

Budapest Gambit: Budapest ...Bb4+ Lines

A52

The full regrouping: the knight recaptures with tempo and Black's pieces hum.

For BlackIntermediate