Reference
Chess Openings A–Z
This is the starting point for 35 major opening-family guides. Each guide explains the resulting positions—not merely a sequence to memorise—with plans for both sides, central structures, critical pawn breaks, sensible piece placement, recurring tactics, and a comparison of the main branches. New to openings? Begin with opening principles before choosing a repertoire.
On this page
Browse by ECO volume
- ECO A — Flank openings (1.c4, 1.Nf3, irregular)
- ECO B — Semi-open games (Sicilian, Caro-Kann, …)
- ECO C — Open games & French (1.e4 e5, 1.e4 e6)
- ECO D — Closed & semi-closed games (1.d4 d5, Grünfeld)
- ECO E — Indian defenses (Nimzo, King’s Indian, …)
The separate complete reference catalogue preserves all 3733 named move-order records. Those records are useful for lookup and repertoire drilling; the family guides contain the strategic explanations.
What is in this catalogue?
- Named move-order records
- 3,733
- Distinct resulting positions
- 3,733
- Records sharing a resulting position
- 0
- Recorded line length (Q1 / median / Q3)
- 6 / 9 / 13 half-moves
- Records by ECO volume
- A 805 · B 764 · C 1244 · D 566 · E 354
These figures describe this local opening book, not how often the openings occur in play. A shared resulting position means that different recorded move orders transpose to the same piece placement, side to move, castling rights and en-passant state.
Most extensively catalogued families
- Sicilian Defense (385 move-order records · ECO B20–B99)
- Ruy Lopez (234 move-order records · ECO C60–C99)
- French Defense (211 move-order records · ECO C00–C19)
- Italian Game (184 move-order records · ECO C50–C59)
- Queen's Gambit Declined (171 move-order records · ECO D02–D69)
- English Opening (166 move-order records · ECO A10–C20)
- King's Gambit Accepted (137 move-order records · ECO C33–C39)
- King's Indian Defense (119 move-order records · ECO E60–E99)
- Caro-Kann Defense (107 move-order records · ECO B10–B19)
- Nimzo-Indian Defense (98 move-order records · ECO E20–E59)
Major opening guides A–Z
Every indexed opening guide is listed here; exact variations then link back to the full family lesson and catalogue.
Alekhine Defense
Alekhine’s Defense through the invited e5 advance, Black’s attacks on d4 and e5, knight routes, and the structural choices in the Modern, Exchange, and pawn-advance systems.
Benko Gambit Accepted
The accepted Benko through Black’s half-open a- and b-files, White’s extra pawn and d5 centre, the ...e6 counterbreak, queenside piece pressure, and the main ways to return the pawn.
Benoni Defense
The Benoni through White’s d5–e4 centre, Black’s queenside majority, the ...b5 and ...f5 breaks, and the contrast between Modern and Czech structures.
Bishop's Opening
The Bishop’s Opening through its delayed knight development, pressure on f7, the d4 and f4 breaks, and its transpositions to Italian, Vienna, and gambit structures.
Bogo-Indian Defense
The Bogo-Indian Defense through the 3...Bb4+ check, White’s main replies, the ...c5 and ...d5 breaks, and the trade between bishop activity and control of e4.
Caro-Kann Defense
A guide to Caro–Kann structures: how ...c6 supports ...d5, where the light-squared bishop belongs, and how the Advance, Classical, Exchange, and Panov systems differ.
Catalan Opening
The Catalan through its g2-bishop, pressure on d5 and c6, recovery of c4 in open lines, and the central e4 and ...c5 breaks.
Dutch Defense
A guide to the Dutch through its early ...f5 commitment, the e4 and ...e5 breaks, Stonewall outposts, Leningrad pressure, and the problem of the c8-bishop.
English Opening
Understand the English Opening by structure: reversed Sicilian positions, symmetrical systems, Hedgehog setups, central transpositions, and the timing of d4 and e4.
Four Knights Game
The Four Knights Game through its symmetrical development, the d4 and ...d5 breaks, Spanish and Scotch structures, and the tactical consequences of an early ...Nd4.
French Defense
A structural guide to the French Defense: the e5–d4 pawn chain, Black’s ...c5 and ...f6 breaks, the c8-bishop, and the main choices for White.
Grünfeld Defense
The Grünfeld through pressure on White’s pawn centre, the ...c5 counterstrike, the g7 diagonal, and the tactical targets on d4 and c3.
Italian Game
Learn the Italian Game through the d4 break, pressure on f7, quiet c3–d3 structures, the Two Knights Defense, and the Evans Gambit.
King's Gambit Accepted
The King’s Gambit Accepted through White’s half-open f-file, Black’s extra f4-pawn, the central d4 and ...d5 breaks, and the difference between holding and returning the gambit pawn.
King's Indian Attack
The King’s Indian Attack as a structure rather than a script: the e4–e5 advance, kingside piece routes, c4 and ...c5 breaks, and the adjustments required by Black’s centre.
King's Indian Defense
A strategic guide to the King’s Indian Defense: locked centres, opposite-wing play, ...e5 and ...c5 breaks, piece routes, and the main white systems.
London System
The London System through its d4–e3–c3 triangle, the e4 and c4 breaks, Black’s ...c5 and ...Qb6 pressure, and the adjustments required against a kingside fianchetto.
Modern Defense
The Modern Defense through its delayed knight development, the flexible ...c5, ...e5, and ...d5 breaks, and White’s choices between central space and rapid attack.
Nimzo-Indian Defense
A strategic guide to the Nimzo-Indian: the pin on c3, bishop-pair bargain, doubled c-pawns, central breaks, piece placement, and the principal white systems.
Petrov's Defense
The Petrov through the mutual attack on e4 and e5, central d-pawn breaks, open e-file tactics, and the choices between classical, modern, and gambit play.
Philidor Defense
The Philidor Defense through its e5–d6 centre, the ...d5 freeing break, Hanham and exchange structures, and the cost of restricting the f8-bishop.
Pirc Defense
The Pirc through White’s broad centre, Black’s g7-bishop, the ...e5 and ...c5 counterstrikes, and the distinct demands of the Austrian, Classical, and 150 Attack.
Queen's Gambit Accepted
The Queen’s Gambit Accepted through temporary control of c4, White’s e4 centre, Black’s ...c5 and ...e5 breaks, and the structures after recovery of the pawn.
Queen's Gambit Declined
A guide to Queen’s Gambit Declined structures: the Carlsbad minority attack, central e4 and ...c5 breaks, piece placement, and major branches.
Queen's Indian Defense
A guide to the Queen’s Indian battle for e4, Black’s queenside fianchetto, the ...c5 and ...d5 breaks, and White’s main development systems.
Réti Opening
The Réti Opening through pressure on d5, the choice between d4 and a flank centre, Advance and Accepted structures, and common Anglo-Slav transpositions.
Ruy Lopez
Understand the Ruy Lopez through its central tension, manoeuvring plans, ...d5 break, and the strategic differences between the Berlin, Exchange, and closed systems.
Scandinavian Defense
A guide to the Scandinavian’s immediate ...d5 challenge, queen- and knight-recapture systems, central breaks, and the cost of developing with attacks on the queen.
Scotch Game
The Scotch explained through its early central exchange, the ...d5 counterbreak, open-file development, and the structural choices after Nxc6.
Semi-Slav Defense
The Semi-Slav through its d5–c6–e6 triangle, the ...c5 and ...e5 releases, Meran queenside expansion, and the forcing choices after Bg5.
Sicilian Defense
A practical guide to Sicilian structures: why 1...c5 creates an unbalanced game, the central breaks both sides need, and how the main systems differ.
Slav Defense
The Slav through its supported d5-pawn, active c8-bishop, ...c5 and ...e5 releases, and the practical difference between main-line and Exchange structures.
Tarrasch Defense
The Tarrasch through its immediate ...c5 challenge, the isolated d5-pawn, active-piece compensation, the ...d4 advance, and White’s blockade strategy.
Trompowsky Attack
The Trompowsky Attack through the 2.Bg5 pin, doubled-f-pawn choices after Bxf6, the ...Ne4 bishop chase, and the e4, ...c5, and ...d5 breaks.
Vienna Game
The Vienna through White’s flexible second move, the f4 and d4 breaks, Black’s central ...d5 reply, and the difference between gambit and fianchetto systems.