Introduction
The Dutch Defence (1.d4 f5) is a combative reply to 1.d4 that immediately stakes a claim on the centre and kingside. It is less popular than openings like 1.d4 d5 or 1.d4 Nf6, but it has unique advantages: Black avoids symmetry and drawing lines, and fights for initiative from the outset. In particular, Dutch systems seek to prevent White’s early e4 push by play like …Nf6 and …g6. As a ChessBase analysis notes, Black’s goal in the Dutch (as with other king-pawn defences) is to “prevent 2.e4” and then follow up with …Nf6 for control of the e4 square. However, advancing the f-pawn also weakens Black’s kingside and invites sharp lines (such as the Staunton Gambit). The Dutch therefore demands precise play to counterbalance its risks with active counterplay.
For computer engines like Stockfish, using a well-crafted opening book can help steer play into favourable Dutch structures while avoiding dubious continuations. Stockfish itself does not include a built-in database; instead it can read PolyGlot opening books in .bin format. In practice, we must supply Stockfish with a separate .bin book file that contains a repertoire of opening moves. This guide explains how to gather and prepare game data, use tools (such as SCID vs. PC and the PolyGlot utility) to build a .bin book, and tune that book to emphasise strong Dutch lines and safe counterplay moves.
To do this effectively, one typically uses free tools. For example, chess programmers often employ Scid or Scid vs. PC (a modern fork with enhanced features) to manage databases, and PolyGlot (by Ed Schröder) to create and manipulate .bin books. The PolyGlot utility can read PGN game collections and compile them into efficient binary opening books. Scid vs. PC provides a graphical Book Tuning interface to examine and edit those .bin books. Using these, we can adjust move probabilities or add/remove lines so that Black’s Dutch Defence is played with maximum counterplay against White.
In the sections below, we will first review the main Dutch systems and strategic themes, then detail each step of the optimisation process: from collecting games and creating a PolyGlot book to using SCID vs. PC to tune the book, and finally testing and integrating it with Stockfish. Throughout, we will highlight key moves and ideas (such as Black’s central breaks …e6/…e5 for counterplay) that should be included or emphasised in the opening book.
Understanding the Dutch Defence and Its Variations
The Dutch Defence (1.d4 f5) has several major branches, each with its own character. The three main systems are the Leningrad Variation, the Stonewall, and the Classical System. A brief overview:
- Leningrad Dutch: Black adopts a King’s Indian–style setup: …Nf6, …g6, …Bg7 and often …d6 (with the fianchettoed bishop). This system mixes Dutch motives with King’s Indian ideas. White usually fianchettos on g2 while Black contests the centre. The key counterplay for Black comes from preparing …e6 or …e5, striking at the centre and opening lines for Black’s bishops and knights.
- Stonewall Dutch: Black builds a solid pawn triangle with …f5, …e6, …d5 and often …c6/…Nc6. The light-squared bishop is typically on d6. This setup is hard to break but can be somewhat cramped. White may aim for breaks with c4/c5 or a kingside pawn storm. Modern advice suggests that after the usual Stonewall moves, White can improve by moves like Qc2 and Rb1 to prepare b4 or c4–c5. Indeed, as ChessBase notes, in some mainline Stonewalls White can seize an edge with 7.Nc3 and 8.b4, where statistical scores favour White.
- Classical Dutch: Black plays 1…f5 and typically follows with …d6 and …e6 (without an early g6). This is more flexible and resembles the Stonewall with the pawn on e6 instead of e5. Black may delay the bishop development and keeps options open.
A critical test of Black’s setup is the Staunton Gambit: 1.d4 f5 2.e4!? where White sacrifices a pawn for quick central play. Black must be well-prepared to meet this gambit safely. In all lines, Black’s underlying theme is to seek counterplay (“contrajuego”) rather than passive defence. For example, an excellent Spanish tutorial on the Leningrad Dutch notes that “las negras han de efectuar el avance e6 o e5, para conseguir contrajuego en el centro” — i.e. Black should push …e6 or …e5 to gain counterplay in the centre. In practice, our opening book should ensure these thematic breaks are available to Stockfish, while also providing safe moves against White’s active tries.
In summary, the Dutch is double-edged: Black gives up the freedom of …e5 early, but gains dynamic chances. As ChessBase explains, the Dutch “has the advantage that there is no symmetry” and avoids forced draws, at the cost of king-side weaknesses. The engine opening book should reflect this balance: keeping sharp, initiative-giving moves in the repertoire and excluding dubious lines. In the next sections we will see how to assemble and fine-tune such a book in .bin format.
Gathering Game Data and Creating a PolyGlot (.bin) Book
The first practical step is to assemble a collection of games featuring Black’s Dutch Defence. You may start with a large PGN database (for example MegaBase or TWIC archives) and use a database tool to filter it. In SCID vs. PC, you could search for games with the ECO codes A80–A99 (Dutch Defence) or set up a position after 1.d4 f5 and use Current Board Search. Once filtered, save those games to a PGN file. If you have a subscription, the ChessBase Dutch Powerbook (2023 edition) contains over 111,000 games with Dutch Defence motifs, but we can also use public sources. Even engine tournament games (such as from CCRL) can be included – indeed one approach is to use CCRL’s high-rated games to enrich the book.
Having the raw PGN of Dutch games, some cleaning is advisable. Remove duplicates, commentary and variations (Stockfish only needs moves). You can use pgn-extract (free tool) to clean and trim games: for example stripping out non-starting positions, comments, and cutting games to a certain ply depth. The Chess.SE example shows using pgn-extract to ensure each game starts from the initial position (necessary for PolyGlot). In brief, make sure your PGN contains only games from the standard start position, and consider limiting moves to the opening phase (e.g. max 20 plies) if desired.
Next, use the PolyGlot program to compile the .bin book. The basic command is:
polyglot make-book -pgn DutchGames.pgn -bin DutchBook.bin -min-game 5 -max-ply 30
This tells PolyGlot to read DutchGames.pgn and output a book DutchBook.bin. The -min-game 5 option (for example) requires that a move appears in at least 5 games to be included; adjust this threshold based on your data size. -max-ply 30 limits depth. (You can also use -only-white or -only-black if desired, but by default all moves are included.) The example in the Chess.SE guide shows creating two books (a short 16-ply main-line book and a deeper 60-ply book) and then merging them. For instance:
polyglot make-book -pgn cleanedBlack2400.pgn -bin DutchShort.bin -max-ply 20 -min-game 10polyglot make-book -pgn cleanedBlack2400.pgn -bin DutchDeep.bin -max-ply 60 -min-game 3polyglot merge-book -in1 DutchShort.bin -in2 DutchDeep.bin -out DutchFull.bin
This yields DutchFull.bin as a single polyglot book combining main and side lines. You can tune these parameters (min-games, ply) for desired breadth. Be sure to use the latest PolyGlot (download from Rebel13) for best compatibility.
Finally, verify the .bin file contains Dutch lines. In SCID vs. PC or another GUI, open the book and navigate moves after 1.d4. You should see Black replies …f5 (as expected), followed by the book’s responses (e.g. …e6, …g6, …Nc6, etc). If the book is empty or missing lines, re-check your PGN filtering.
At this stage you have a working PolyGlot book DutchFull.bin. Before using it with Stockfish, we will tune and optimize it to emphasise strong Dutch moves and remove weak ones. This is done in SCID vs. PC, as described next.
Using SCID vs. PC to Tune the Dutch Defence Book
With the raw .bin book created, the next step is to adjust move weights and lines so that Stockfish favours good Dutch moves. Scid vs. PC provides a built-in Book Tuning interface for this purpose. First, configure Scid vs. PC to see your book: go to Options → Books Directory and point it to the folder containing DutchFull.bin. Then open Tools → Book Tuning. In the Book Tuning window you will see a drop-down listing your .bin file. Select it to examine its contents.
From here, you navigate the opening moves just like a game. For example, play 1.d4 (White’s move), then 1…f5 (Black’s Dutch move from the book). The Book Tuning pane will now show all possible moves that are in the book from that position. Each move has an integer weight (a percentage) indicating how often it is chosen by the book. These integers are in the range 0–100 and sum to 100. Zero means “very low probability”. You can click on any move to select it, and then use the small spinbox (or up/down arrows) to change its value. This immediately changes the weight of that move, while keeping the others proportionally adjusted once you press Save.
In practice, you will use Book Tuning to promote strong moves and demote or remove weak ones. For example, if you find that the book has any dubious moves for Black after 1.d4 f5 (say, a weakening move not leading to counterplay), you can reduce its weight or set it to 0. Conversely, ensure key Dutch moves (like …Nf6, …e6, …g6, etc.) have healthy weights. The weights are arbitrary integers, but they reflect probability; a weight of 50 is twice as likely as a weight of 25, for instance, given the 100% total.
Besides adjusting weights, you can use Add Line and Remove Line features. If a strong move or variation is missing from the book (perhaps because it was rare in the PGN), you can add it manually. For example, if 2.e4 (the Staunton Gambit) was not in the book, you could use Add Line to insert the sequence 1.d4 f5 2.e4 fxe4 3.Nc3 into the book. (Scid vs. PC will prompt you to input the moves, and it will append that entire branch into the book.) Similarly, use Remove Line to delete a move sequence from a position onward (for example, if a particular line leads to a clear disadvantage for Black, you may excise it from the book). Note that bulk adds/removes are automatically saved into the .bin when applied.
As you tune, keep these guidelines in mind:
- Emphasise counterplay moves: From the critical Dutch positions, ensure Black’s thematic breaks are present. For instance, after a few moves you often want …e6 or …e5 in the book for central counterplay. If either is missing or rare, use Add Line to include it, and increase its weight.
- Include safe replies: Make sure moves that deal with White’s plans are covered. For example, against 2.e4 (Staunton Gambit) and 2.c4 sidelines, verify that the book has sound responses (…fxe4, …Nf6, etc.).
- Prune passive moves: If any move consistently yields poor evaluations, lower its weight or remove it. For example, if …h6 or …a6 early is poor, you may reduce these.
- Maintain variety: A strength of opening books is variety. If two moves are both reasonable (say …Nf6 and …Nc6 in a position), keep both with balanced weights to mix play.
Use Book Tuning as an interactive GUI. You will see the board diagram and the tree of moves. You can navigate by making moves on the board or clicking lines in the tuning window. Whenever you set a new weight or add/remove, press Save to commit. The .bin file is updated in place.
By iterating through key Dutch positions (e.g., after 1.d4 f5 2.g3, 2.e4, 2.c4, 2.Nf3, etc.) you can systematically optimise the book. The result should be a polyglot book where Stockfish playing Black will naturally lean towards dynamic, well-evaluated Dutch continuations, rather than random or bad lines.
Incorporating Counterplay and Advanced Lines
A crucial part of optimisation is deliberately including counter-attacking ideas for Black. Recall that Black’s plan in the Dutch is to fight for the centre and kingside initiative. Thus, ensure that central pawn breaks are in the book. The Spanish source we cited stressed that “…e6 or …e5” are needed for counterplay. In book tuning, you should verify that after typical moves (for example, 1.d4 f5 2.Nf3) the moves …e6 and …e5 appear in the list. If not, use Add Line to insert them. Set their weights to significant values. For instance, after 1.d4 f5 2.g3 Nf6 3.Bg2 g6 4.c4, Black’s ambitious response is often …d6 or …Nc6 followed by …e5; these must be represented.
Other counterplay moves to watch for include:
- Knight leaps to e4 or c3: In many Dutch lines, the knight can jump into e4 (after …Ne4) to exert pressure. If the raw book underweights …Ne4, raise it.
- Kingside pawn moves: Moves like …h6 or …g5 can be sharp (for example, preventing Bg5 or grabbing space). Include these where typical; in Leningrad setups, …h6 is often played to stop White pins.
- Unbalanced breaks: Sometimes Black plays …c5 or …b6 to challenge White on the queenside – consider if your book should contain lines like …c5 in the Stonewall, or …b6 after …c5.
Finally, ensure that the book covers White’s active tries. The Staunton Gambit (1.d4 f5 2.e4) deserves its own branch. You might add the main Staunton line so that Stockfish knows how to meet it without venturing into the raw engine (or losing). Similarly, against early c4 setups (Queen’s Gambit style), the book should include …Nf6 and …e6 lines for Black.
You can summarise important ideas with lists in your notes. For example:
- Central breaks: Prioritise …e6 and …e5 to open lines and gain central space.
- King-safety moves: Include …h6 or …g6 when appropriate to safeguard the king.
- Active defences: Ensure lines like …fxe4 in the Gambit or …d5 in the Stonewall are present.
By systematically reviewing and adding these lines, the book will embody Black’s counterplay plans. Whenever you add a line, its moves will appear in the Book Tuning interface, and you can then set their weights. Conversely, if you know a line is inferior for Black, remove it. The goal is a coherent Dutch repertoire in the book.
Testing and Integrating the Optimised Book
After tuning, it is important to test the new book with Stockfish. Load DutchFull.bin as a PolyGlot book in your GUI or engine adapter. Then let Stockfish play some games as Black, either against itself with White side book or against another engine. Observe whether it now chooses the Dutch lines you expect. For example, after 1.d4, does Stockfish play 1…f5? If so, check that the subsequent responses match the tuned moves (…e6, …Nf6, etc.).
You can also run a batch of automated games: for instance, play a Dutch Book-enabled Stockfish against a baseline engine (like another Stockfish without the book, or with a generic book). See if Black’s results with Dutch 1…f5 improve relative to not using the specialised book. The Computer Chess Rating Lists (CCRL) format is an example of such testing. In fact, CCRL’s 40/15 tests used a “General book (up to 12 moves)” for all engines. You could mimic this by having the book depth limited. If desired, create an additional “General” book or adjust your book depth to match CCRL’s conditions for a fair comparison.
If weaknesses are found (for example, Stockfish as Black blunders after a certain White move), return to SCID vs. PC and update the book. It is an iterative process: tune in SCID, test in engine matches, refine, and repeat.
Once satisfied, integrate the book into your regular Stockfish setup. Many GUIs allow specifying a polyglot book file for an engine. When Stockfish is launched with that book enabled, it will consult it on the first moves until the book runs out (then continue with its own search).
Through this process, the Dutch Defence is now optimised for engine play: Black will tend to play sharp, sound lines with plenty of counterplay. The combination of curated master/engine games and targeted tuning ensures Stockfish is well-prepared whenever White plays 1.d4.
Conclusion
Optimising the Dutch Defence in a chess engine’s opening book involves both art and science. On the technical side, we gathered games, used PolyGlot to build a .bin book, and leveraged Scid vs. PC’s tuning features to refine it. We used SCID vs. PC’s Book Tuning to edit the book interactively, ensuring that high-quality Dutch lines were kept and weaker ones removed. The guide above provided step-by-step instructions: filtering PGN for Dutch games, creating short and deep books with PolyGlot, merging them, and then adjusting move weights and adding key variations (like …e6/…e5 breaks).
Equally important was the strategic understanding: the book was crafted with Black’s counterplay in mind. We ensured that thematic ideas – central pawn advances, active knight moves, safe king-side moves – are present. The Dutch’s dynamic nature was preserved by favouring moves that challenge White. For example, boosting the weight of …e6/…e5 options gives Black immediate central counter-thrust. This blends the data-driven approach (games from master and engine play) with chess insight, which is key to a strong book.
Finally, we stressed testing. An optimised book should be vetted by playing it out in practice games, adjusting further if unexpected blunders occur. This closes the loop: create – tune – test – refine. Throughout, we used clear, documented methods and free tools, ensuring the process is reproducible. In short, with careful data selection and SCID vs. PC tuning, one can produce a robust .bin opening book that lets Stockfish handle the Dutch Defence confidently and creatively. Any chessengine enthusiast can follow this guide to achieve a complete, high-quality Dutch Defence book – and the same principles apply to other openings as well.
Sources: The methods and ideas above are drawn from chess database manuals and community examples, including ChessBase analyses of the Dutch and technical guides on PolyGlot and Scid vs. PC. Each step was cross-referenced with authoritative documentation to ensure accuracy.
Jorge Ruiz Centelles
Filólogo y amante de la antropología social africana