Master every chess opening, one guide at a time.
From the Ruy Lopez to the Grünfeld — clear move orders, strategic ideas, traps and model lines for every opening and defence in the ECO encyclopedia. Free forever.
1,506
In-depth guides
500
ECO codes A00–E99
69
Opening systems
937
Named variations
Start here
Featured guides
The openings that decide more games than any others — each with a full interactive walkthrough.
Sicilian Defence, Najdorf Variation
B90The Najdorf is chess at its most ferocious. Black's humble 5...a6 does three jobs at once — it stops Bb5, prepares ...b5 expansion and lets the queen roam — and in return White gets a free hand in the centre. What follows is a knife fight where both players know that one slip decides everything. Fischer and Kasparov both trusted it at the very top, which tells you everything about its fighting credentials.
Ruy Lopez
C60The Ruy Lopez is chess's cathedral — every world champion has prayed here. White's bishop pins the c6-knight against the e5 pawn, building the slow, inexorable squeeze that made Capablanca, Fischer and Karpov immortal. Black has a dozen rich defensive systems, from Kramnik's Berlin Wall to Kasparov's Marshall Attack.
King's Indian Defence
E60The King's Indian is chess's great romance: Black invites White to build the biggest centre in the opening, then burns it down with ...e5, ...f5 and a full-scale pawn storm. Fischer's devastations, Kasparov's Mar del Plata brilliancies and Radjabov's modern revivals all flow from the same fearless idea.
Italian Game
C50The Italian Game is where most players fall in love with chess — and where the modern elite now spend their theory budgets. The Giuoco Pianissimo squeezes are the new main lines: slow, rich, and full of long-term plans that reward deep understanding.
Queen's Gambit Declined
D30The Queen's Gambit Declined is the most respected defence in chess history — every world champion has defended it and attacked it. Black accepts slight cramping for a rock-solid structure, and the middlegames test deep understanding: minority attacks versus c5 breaks, light-square wars and endgame technique.
Grünfeld Defence
D80The Grünfeld is hypermodern dynamism in its purest form: Black hands White the entire centre, then attacks it from the flanks with the mighty g7-bishop and relentless piece pressure. It is the opening of Fischer's Game of the Century and of every engine-era warrior.
Nimzo-Indian Defence
E20Aron Nimzowitsch's 1910s masterpiece remains the most respected way to meet 1.d4: the ...Bb4 pin fights for e4, pressures c3 and offers structural concessions for the bishop pair. A century of world champions — from Capablanca and Botvinnik to Carlsen and Caruana — made it their main weapon.
French Defence
C00The French Defence is the opening of strategic counterpunchers: Black invites White to build a big centre, then spends the whole game hammering at it. The bad bishop on c8 is a small price for the healthiest structure in chess — Botvinnik, Korchnoi and Morozevich all made it their life's work.
The encyclopedia
Browse by ECO volume
The Encyclopaedia of Chess Openings sorts every opening into five volumes. Each volume below has its own page with every code from 00 to 99.
Flank & Uncommon Openings
1.c4, 1.Nf3, 1.f4 & the sharp d4 defences
A00–A99333 guides
BSemi-Open Games
The Sicilian & the fighting 1.e4 defences
B00–B99348 guides
COpen Games & the French
1.e4 e5 classics & the French Defence
C00–C99335 guides
DClosed & Semi-Closed Games
Queen's Gambit, Slav & Grünfeld
D00–D99249 guides
EIndian Defences
Nimzo, King's Indian & Catalan
E00–E99241 guides
Curated paths
Collections
Repertoire-ready groupings — pick the collection that matches your style and level.
Openings for White
Repertoire anchors for the player of the white pieces — from classical main lines to universal systems.
Openings for Black
Defences and counters with the black pieces — solid fortresses, dynamic counterattacks and everything between.
Beginner-Friendly Openings
Openings with clear plans and light theory — ideal for players building their first serious repertoire.
Gambits & Sacrifices
Pawn offers, piece sacs and all-out attacks — the most romantic and double-edged lines in the encyclopedia.
Attacking Openings
Sharp, aggressive systems where the fight starts early and the kings are the first targets.
Positional Openings
Structures, plans and slow squeezes — openings that reward understanding over memorisation.
Hypermodern & Fianchetto
Attack the centre from a distance — fianchettoed bishops and piece pressure instead of pawn grabs.
Elite Favourites
The main lines the world's best players trust when everything is on the line.
Frequently asked questions
Your next favourite opening is one search away.
Every guide is free, interactive and written for players who want to understand — not just memorise.