Chess Engines Diary

The LesChat s opening book series is produced by Jordi Ruiz Centelles. Depth=40 bestmove disable variety=2 Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  LesChats 24042025 book (.bin) - down...

  Optimus -  bin opening book. Book - BIN format  ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Optimus 2502 (bin file) download

  We provide two opening books, in two different formats: bin and ctg. This is enough to be used in almost any chess program (GUI). Of course, every book may contain errors, but this one is based on a high rating. Happy testing! Book - CTG format Customers who wish to use the CTG format book will need a GUI capable of reading this format, ie. Chessbase GUIs.  Please save the book in your book folder. We strongly recommend that you "Optimize" the book in the Book options dialog so the tournament moves are chosen. The book is very wide even in tournament mode unlike most other books. A type of book format mainly used by chess programs from Chessbase , such as Fritz, Chess Base, Komodo, FatFritz, Houdini , etc. Book - BIN format (  Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they ar...

  Open-chess2  -  bin opening book. Book - BIN format  ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Open-chess 2 101224 (bin file) download CTG , (ChessBase Opening Tree of Games) an open...

  Terk  -  bin opening book. Book - BIN format  ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Broth 07122024 (bin) download

ABK , (Arena's book format) - the opening book format of Arena. It persists a book tree as array of entries, each entry referring one book move with priority and statistics, an entry index of the next move inside a book line (> 0 if any), and an entry index of a possible sibling move (>= 0 if any). The sizeof of an entry is 28, the initial position indexed by 900.(ChessWiki). Arena Big Daddy Book v4 STP - this is a very large debut book (over 2 GB when unpacked) that will work well in GUI Arena.   Arena Big Daddy Book v4 download

DarthVader - ctg opening book . CTG , (ChessBase Opening Tree of Games) an opening book format by ChessBase, supported by their Fritz GUI and ChessBase GUI, and therefore used by all chess engines compatible with these commercial user interfaces. Each Chessbase book consists of four files, the binary CTG file contains the real data, the INI text file provides auxilliary information, the CTB file some kind of bitmap over free pages in the CTG file, and the CTO file, containing a lookup table into the CTG file for fast indexed access. Only White to move positions along with its moves, annotations and engine recommendations, and statistics are stored, probing black positions requires color flipping, of course including en passant square and castling rigths. Further, if the white king is on files a-d, and neither side has any castling rights remaining, the board is mirrored horizontally. The CTG file is organized in 4KiB pages, the first page contains header information such as the number ...

Terk  - bin opening book. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Terk (bin) download

Geralt  - bin opening book. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Geralt (bin) download

Eman  -  bin opening book. Eman is a chess engine that has achieved a Chess Engines Diary CEDR=3752 rating. Here we have a strong opening book. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 byt...

Big Castle opening book by Ian Hurnavich - bin opening book. Best Move off depth 100 Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Download link for Big Castle (.bin) opening book: Big Cast...

The LesChat s opening book series is produced by Jordi Ruiz Centelles. Depth=40 bestmove disable variety=2 Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  LesChats 171024 book (.bin) - downlo...

Dara opening book series is prepared by the user named "Alisyadara". CTG , (ChessBase Opening Tree of Games) an opening book format by ChessBase, supported by their Fritz GUI and ChessBase GUI, and therefore used by all chess engines compatible with these commercial user interfaces. Each Chessbase book consists of four files, the binary CTG file contains the real data, the INI text file provides auxilliary information, the CTB file some kind of bitmap over free pages in the CTG file, and the CTO file, containing a lookup table into the CTG file for fast indexed access. Only White to move positions along with its moves, annotations and engine recommendations, and statistics are stored, probing black positions requires color flipping, of course including en passant square and castling rigths. Further, if the white king is on files a-d, and neither side has any castling rights remaining, the board is mirrored horizontally. The CTG file is organized in 4KiB pages, the first page...

Dara opening book series is prepared by the user named "Alisyadara". Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Dara 141024 (bin) download

Big Castle opening book by Ian Hurnavich - bin opening book. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Download link for Big Castle (.bin) opening book: Big Castle (bin) download

  The author of the Adrio opening book series is Ian Hurnavich . Book - BIN format (  Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Adrio Pro 250824 download

The LesChat s opening book series is produced by Jordi Ruiz Centelles. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  LesChats 240824 book (.bin) - download

  The author of the Adrio opening book series is Ian Hurnavich . Book - BIN format (  Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  Adrio Pro 170824 download

The LesChat s opening book series is produced by Jordi Ruiz Centelles. Book - BIN format ( Used by chess GUIs Arena, Banksia and Droidfish) Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information.  At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of top books is built and worked with hash values from transpositions. Often each position is stored as a hash value (8 bytes) and some extra information such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position. To save space those extra information typically about 2-8 bytes.  LesChats 110824 book (.bin) - download

Dear chess and chess engine lovers, The " download " subpage on the blog is being reorganized. This is a huge amount of data, so it will take some time. From time to time we add links to megapacks of chess engines, opening books, games and other files. Check the download page regularly - we will improve and add links. Opening Book (bin) Adrio Pro 230724 Esculapio Adrio Pro 210624 AdrianOliva Pampa3 bin (May 2024) OPTIMUS 3.2 Student Opening Book DONb free Little Cat 8.6c M11.2 Perfect 2021 Ranomi 170527 CerebellumLight Morphius 12.9c Chiron 1.5 Hannibal Small Aarica 2012 Stockfish-211-book CTG , (ChessBase Opening Tree of Games) an opening book format by ChessBase, supported by their Fritz GUI and ChessBase GUI, and therefore used by all chess engines compatible with these commercial user interfaces. Each Chessbase book consists of four files, the binary CTG file contains the real data, the INI text file provides auxilliary information, the CTB file some kind of bitmap over...