You need two: an answer to 1.e4 and an answer to 1.d4. Here are the soundest of each.
The best chess openings for Black are the Sicilian Defense, Caro-Kann Defense and French Defense against 1.e4, and the Nimzo-Indian Defense, King's Indian Defense and Slav Defense against 1.d4. Because Black does not choose the first move, a repertoire needs at least two of these — one for each of White's main opening moves.
1.e4 is the move you will face most often, so this is the first gap to fill in a repertoire. The choice is broadly between meeting it symmetrically with 1...e5 and fighting for an asymmetric game.
1.e4 c5
The most popular answer to 1.e4 and the best-scoring one for Black at master level. Choose it when you want to play for a win, not a draw.
Black accepts a slight lag in development in exchange for a queenside pawn majority and the half-open c-file, which becomes the main artery for counterplay. White typically attacks on the kingside while Black attacks on the queenside, so games often become a race in which tempo matters more than material.
Best suited to: Players who want winning chances with Black and are willing to learn theory. The main lines are heavily analysed, and being caught unprepared in the Najdorf or Dragon can lose quickly.
1.e4 c6
Supports the d5 advance with the c-pawn instead of the e-pawn, so Black's structure stays sound and the light-squared bishop gets out before it is locked in.
Black gets a sound pawn structure and few weaknesses, usually at the cost of some passivity in the opening. Many lines transpose into endgames where Black's structural solidity is an asset, which is why the Caro-Kann is often described as the drawing weapon that still plays for a win.
Best suited to: Players who value structural soundness and are comfortable with slightly slower positions. Also a practical choice for anyone who wants one reliable answer to 1.e4 without heavy theory.
1.e4 e6
Builds a solid pawn chain and cedes space to counterattack it later. Reliable, at the cost of a passive light-squared bishop.
The defining feature is the pawn chain. White's pawns typically run d4-e5 and Black's e6-d5, and both sides attack the base of the opponent's chain: Black plays c5 and f6, while White expands on the kingside. Positions are usually closed and strategically rich.
Best suited to: Players who like a defined plan from move one and do not mind defending. The French rewards understanding of pawn structure more than it rewards tactics.
1.e4 d5
Challenges the centre on move one. The smallest theory burden of any 1.e4 answer, which makes it a common first choice.
Black loses a little time with the queen but gets a simple, clear position with no long-term weaknesses. Because there are far fewer branches than in the Sicilian or French, it is one of the least theory-heavy answers to 1.e4.
Best suited to: Players who want a reliable defence to 1.e4 with a small amount of theory to learn.
1.e4 d6
Lets White build a big centre, then attacks it with pieces and pawn breaks rather than occupying it.
Flexible and somewhat provocative. Black's position is compact but passive early, and against the sharpest setups such as the Austrian Attack, precise play is required to avoid being overrun.
Best suited to: Players who like counterattacking positions and are comfortable being objectively slightly worse in exchange for flexibility.
1.e4 e5 2.Nf3 Nf6
Answers 2.Nf3 by mirroring with 2...Nf6. Leads to symmetrical positions and is a well-established way to steer toward a draw with Black.
Symmetrical and simplifying. Many lines lead to early exchanges and level endgames, which is exactly the point for a player wanting a reliable answer to 1.e4. Sharper attempts by White exist but require Black to know a limited amount of theory.
Best suited to: Players who want a low-risk, low-theory answer to 1.e4 and are content to play for equality first.
1.e4 g6
Fianchettoes immediately and keeps the move order flexible, so it transposes into several other defences depending on what White commits to.
Extremely flexible and transpositional — the Modern can turn into a Pirc, a King's Indian, or something entirely its own. That flexibility is also its cost, since Black concedes the centre early and must handle a wide range of White setups.
Best suited to: Experienced players who understand structures well enough to navigate transpositions and who prefer avoiding mainstream theory.
1.e4 Nf6
Invites White's pawns forward with 1...Nf6 to attack the overextended centre afterwards. Provocative by design.
Provocative by design. After 2.e5 Nd5 3.d4 d6 White has an imposing centre and Black has spent moves on a single knight — the whole opening rests on whether that centre proves strong or loose.
Best suited to: Players who understand hypermodern ideas and want to take opponents out of familiar territory with Black.
Against 1.d4 the main decision is whether to contest the centre with a pawn on d5 or to control it with pieces from a distance — the Indian defences.
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4
Pins the c3 knight and fights for the centre with pieces. One of the most respected defences to 1.d4 at every level.
The central question is whether Black's willingness to trade the bishop for the knight — often doubling White's c-pawns — is worth the structural concession. Black gets long-term pressure on the light squares; White gets the bishop pair and a broad centre.
Best suited to: Players who understand structural imbalances and enjoy positions where a small permanent feature, like doubled pawns, defines the plan for both sides.
1.d4 Nf6 2.c4 g6 3.Nc3
Concedes the centre, then breaks with ...e5 or ...c5 and attacks on the kingside. The sharpest of the Indian defences.
The classic King's Indian is a race: White plays on the queenside where the space advantage is, Black pushes pawns at the white king on the other wing. Because both attacks proceed independently, the games are unusually sharp and rarely end in draws.
Best suited to: Attacking players who want unbalanced positions with Black and are willing to accept worse positions objectively for practical winning chances.
1.d4 d5 2.c4 c6
Supports d5 with the c-pawn, keeping the structure solid without shutting in the light-squared bishop as the Queen's Gambit Declined does.
Black often follows with dxc4 and b5 to hold the pawn temporarily, gaining time to develop the bishop outside the pawn chain. The resulting positions are solid but less passive than the Declined, with the c8 bishop playing an active role.
Best suited to: Players who want the solidity of the Queen's Gambit Declined without locking in the light-squared bishop.
1.d4 d5 2.c4 e6
The classical answer: hold d5 with the e-pawn and accept a slightly passive but very sound position.
Black shuts in the light-squared bishop with e6 in exchange for a stable centre. The recurring strategic themes are freeing the position with c5 or e5, and the minority attack, where White advances the queenside pawns to create a weakness in Black's structure.
Best suited to: Players who want a dependable answer to 1.d4 and are comfortable in classical positions where small structural advantages decide the game.
1.d4 Nf6 2.c4 g6 3.Nc3 d5
Lets White build a broad pawn centre and then targets it with the fianchettoed bishop. Requires accurate play but scores well.
White gets a big centre and space; Black gets piece pressure aimed at it and a clear plan. If White's centre holds, White is usually much better; if Black dissolves it, Black's activity tells. There is little middle ground, which is what makes it sharp.
Best suited to: Players comfortable with dynamic positions where piece activity has to compensate for a spatial disadvantage.
1.d4 Nf6 2.c4 e6 3.Nf3 b6
Fianchettoes the queen's bishop to contest the long diagonal. A quieter companion to the Nimzo-Indian in the same repertoire.
Solid and manoeuvring. Black keeps the position under control and contests the centre with pieces rather than pawns, leading to positions that are hard to break down but that require patience to play for a win.
Best suited to: Positional players who already play the Nimzo-Indian and need a consistent answer to 3.Nf3.
1.d4 f5
Answers 1.d4 with 1...f5, fighting for e4 and aiming at kingside play. The most unbalancing reply available.
Three distinct systems share the move order: the Stonewall, where Black builds a fixed pawn wall and attacks; the Leningrad, which combines f5 with a kingside fianchetto; and the Classical, a more restrained setup. Each produces genuinely different middlegames.
Best suited to: Attacking players who want to dictate the character of the game with Black rather than react to White's choice.
1.d4 Nf6 2.c4 c5
Accepts a structural concession for a queenside pawn majority and open lines. Double-edged and sharp.
Highly unbalanced. White has a protected passed pawn on d5 and a central space advantage, while Black plays for ...b5 and pressure down the long diagonal. Objectively risky, but it generates winning chances against opponents who play for a draw.
Best suited to: Aggressive players who need to win with Black and accept theoretical risk to do it.
Start with 1.e4, because it is the move you will face most often. Pick one answer and play it until the resulting positions feel familiar, then do the same against 1.d4. Two openings you know well beat five you half-remember.
Pair openings by temperament rather than mixing them. The Caro-Kann and Slav make a low-maintenance, solid repertoire that asks for little memorisation. The Sicilian and King's Indian make an ambitious one that plays for a win with Black but demands real study time to hold up.
The opening explorer covers all 3,174 named openings on an interactive board, and you can check your own games against them with free Stockfish analysis.