What Opening Does Stockfish Use? Complete Guide to the Engine’s Opening Choices

Stockfish isn’t just any chess engine — it’s the world’s strongest open-source engine, crushing everything from club players to world champions. And if you’ve ever asked yourself what opening does Stockfish use, you’re touching on one of the hottest debates in online chess circles. 

Unlike humans, who might stick to a pet opening, Stockfish evaluates positions objectively. That means its opening choices shift depending on calculation depth, evaluation horizon, and updates in its algorithm. 

Let’s dig into what moves Stockfish actually prefers, what openings it gravitates toward as both White and Black, and how you can use those insights in your own games.

What Is Stockfish?

Stockfish is a free, open-source chess engine and one of the strongest ever built. First released in 2008 as a fork of Glaurung, it’s developed by a global community and licensed under GPLv3. Unlike commercial engines, anyone can use, modify, and integrate Stockfish into apps and sites — which is why platforms like Lichess and Chess.com rely on it.

The engine combines deep search algorithms with NNUE (Efficiently Updatable Neural Network) evaluation, making it fast, precise, and adaptive. It also supports endgame tablebases for flawless play in simplified positions.

Today, Stockfish dominates engine tournaments like the Top Chess Engine Championship (TCEC) and is the go-to tool for players worldwide to analyze games, explore openings, and train more effectively. In short: it’s free, brutally strong, and constantly improving thanks to open-source collaboration.

Stockfish’s First Moves as White

When given the White pieces, Stockfish evaluates several first moves very closely. Analysis across versions (from SF 13 to SF 17) shows a consistent top tier: 1.e4, 1.d4, 1.Nf3, and 1.c4.

• 1.e4: The classical King’s Pawn Opening. Stockfish often leans toward this move at shallow depths because it directly contests the centre and opens lines for both the bishop and queen.

• 1.d4: Slightly more positional, with long-term stability. At deeper search depths, Stockfish tends to rank 1.d4 almost equal with 1.e4.

• 1.Nf3: A flexible move, often chosen at extreme calculation depths. It doesn’t commit to a pawn structure and allows transpositions into Queen’s Gambit, English, or Catalan setups.

• 1.c4: The English Opening. Stockfish likes this because it avoids immediate theory battles while keeping options wide.

What’s fascinating is that Stockfish’s preferences shift as depth increases. At 10 plies, 1.e4 might dominate. By 40+ plies, 1.Nf3 or 1.c4 often rise in evaluation, showing the engine’s bias toward flexible setups at long horizons.

Stockfish’s Core Opening Repertoire

Stockfish doesn’t just stop at move one. Its “engine repertoire” has been mapped out by grandmasters like Matthew Sadler. Certain systems stand out as Stockfish’s go-to choices, especially in long engine matches.

Sadler’s research shows that Stockfish gravitates toward openings that are ultra-solid yet dynamic. For example, it avoids sharp gambits like the King’s Gambit or Benoni because they involve long-term structural concessions. Instead, Stockfish’s “repertoire” is built around openings that stand up well against perfect defense.

Why Stockfish’s Preferences Change

Unlike humans with fixed repertoires, Stockfish’s tastes evolve depending on the circumstances:

• Search Depth: At shallow depth, the engine values direct control (1.e4). At deeper levels, it prefers subtlety (1.Nf3 or 1.c4).

• Evaluation Function Updates: Each Stockfish release changes how it measures imbalances. SF 17, for example, showed different “tastes” from SF 15.

• Hardware / Time: On limited resources, Stockfish may stick to simpler, forcing lines. With infinite time, it may steer toward slow manoeuvring systems.

• Opponent Style: In engine matches, Stockfish chooses openings designed to test weaknesses in other engines (e.g., using the Berlin to frustrate Leela).

Lucidar’s depth analysis shows that at very high calculations, Stockfish’s evaluations converge — meaning it sees several openings as practically equal. For humans, this is a reminder: don’t obsess over which first move is the best.

Stockfish as Black

What about when Stockfish doesn’t get the first move? Its Black repertoire shows just as much discipline.

• Against 1.e4: Stockfish often recommends the Berlin Defense (1…e5 2.Nf3 Nc6 3.Bb5 Nf6). It’s drawish but extremely solid. Another choice is the French Defense (1…e6), which creates a resilient pawn chain.

• Against 1.d4: Stockfish tends toward the Queen’s Gambit Declined or the Ragozin Defense, both offering balance between defense and counterplay. Nimzo-Indian setups also appear frequently.

• Against 1.Nf3 / 1.c4: Stockfish often transposes back into QGD-style or Catalan-style structures, again favoring solidity.

The key is that Stockfish rarely opts for speculative defenses like the King’s Indian or the Benoni. While those are playable, the engine rates them as too risky against perfect play.

What Players Can Learn from Stockfish’s Openings

Following Stockfish’s lead can make your repertoire more resilient:

1. Choose openings that are both solid and flexible. Instead of flashy gambits, go for systems like the Ruy Lopez, QGD, or English.

2. Use transpositions. Moves like 1.Nf3 let you adapt based on your opponent’s replies, a tactic Stockfish uses constantly.

3. Study endgame-rich openings. The Berlin, for example, funnels straight into positions Stockfish loves because it can squeeze advantages in endings.

4. Understand ideas, not just moves. Stockfish doesn’t “memorize” openings. It evaluates ideas: pawn structure, piece mobility, and long-term safety. Humans should adopt the same mindset.

5. Be aware of the shifting theory. Stockfish’s preferences evolve with each new version. What’s “best” today may look different in SF 20.

By emulating the engine’s discipline — choosing openings that don’t collapse and leave room to outplay opponents later — your own repertoire becomes harder to crack.

FAQs

Does Stockfish use an opening book?

Yes, Stockfish can use an opening book, but it doesn’t rely on one the way humans do. Out of the box, Stockfish calculates moves from scratch using its evaluation and search algorithms. However, many platforms (like chesscheatsheets.com) pair it with large Polyglot opening books so it can follow established theory in the first 15–20 moves. 

This avoids wasting time “reinventing” common openings such as the Ruy Lopez or Queen’s Gambit. If no book is loaded, Stockfish simply chooses openings by raw calculation depth — which often leads to moves like 1.e4, 1.d4, 1.Nf3, or 1.c4. For practical use, combining Stockfish with an opening book gives the most accurate, human-friendly preparation.

What strategy does Stockfish use?

Stockfish’s “strategy” is not fixed like a human’s repertoire; instead, it uses a blend of search algorithms and neural network evaluation (NNUE) to choose the best move in every position. In openings, this strategy usually means controlling the centre, developing pieces efficiently, and avoiding long-term weaknesses. 

Unlike gambit-loving humans, Stockfish avoids speculative sacrifices unless they show clear compensation. The engine also prefers openings that keep flexibility — systems like the Berlin Defense, Ragozin, or English Opening. Its broader “strategy” can be described as: play solid, play safe, and squeeze long-term advantages. 

This is why Stockfish’s opening use feels conservative compared to Magnus Carlsen or Hikaru Nakamura, but remains devastating against both engines and human players.

What is the best depth for Stockfish?

The “best” depth for Stockfish depends on your goal. In practical terms:

• Casual analysis: Depth 20–25 gives reliable evaluations and opening guidance.

• Serious study: Depth 30–40 is excellent for preparing openings Stockfish prefers (like 1.e4 → Berlin Defense, or 1.d4 → Ragozin).

• Engine competitions: Depth often exceeds 50, using cluster hardware and hours per move.

The higher the depth, the more accurate Stockfish’s judgment of which opening is best. For example, at shallow depth, it might choose 1.e4; at extreme depth, moves like 1.Nf3 or 1.c4 rise in value. For most club players, aiming for depth 25–30 is the sweet spot: fast enough to be practical, deep enough to see which openings Stockfish genuinely trusts.

What are the disadvantages of Stockfish?

Despite its strength, Stockfish isn’t perfect. Its main disadvantages include:

1. Resource-Intensive: At high depths, Stockfish requires robust hardware and lengthy calculation times.

2. Over-objectivity: It avoids “messy” openings like the King’s Gambit or Benoni, which means its choices can feel too conservative for players who thrive in chaos.

3. No Human Intuition: While it plays flawlessly, it doesn’t explain ideas clearly. Beginners may struggle to learn why Stockfish prefers an opening.

4. Predictability: Because it often chooses solid lines like the Berlin Defense or Queen’s Gambit Declined, opponents may anticipate its repertoire in engine tournaments.

For training, Stockfish is unbeatable, but players should combine it with human-oriented resources to build intuition and creativity alongside cold precision.

Conclusion

So, what opening does Stockfish use? The answer isn’t just one line—it’s more of a chess philosophy: choose openings that are solid, flexible, and future-proof. As White, Stockfish rotates between 1.e4, 1.d4, 1.Nf3, and 1.c4. As Black, it gravitates toward the Berlin Defense, the French Defense, and lines from the Queen’s Gambit Declined family.

If you want to build a similar kind of opening repertoire—without drowning in theory—here’s your move: check out Chess Cheat Sheets for plug-and-play opening toolkits. They break down key openings move-by-move, include PGN files, help you understand why each move works, not just what, and let you start your games with confidence. 

Use Stockfish as more than a move generator—use it alongside resources like cheat sheets to turn precision into practical advantage.