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Stockfish-ChessBase Lawsuit: It's actually happening!
Stockfish, or something else? Logo originally by Klein Maetschke.

Stockfish-ChessBase Lawsuit: It's actually happening!

the_real_greco
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11

A few months ago ChessBase released Fat Fritz II, setting off a firestorm of criticism from the open-source chess community. I covered that controversy in a previous blog post, predicting that nothing would result other than a lot of shouting. As usual, I was wrong! Today the Stockfish team announced they have filed a lawsuit against ChessBase, claiming a violation of the GPL.

Unfortunately I'm too lazy to write a decent post explaining the details. Instead, I've copied the announcement from the Stockfish Blog. This has been posted on numerous other websites, but I felt it was worth putting on chess.com also. Buckle up; this is going to be fun.


Our lawsuit against ChessBase

The Stockfish project strongly believes in free and open-source software and data. Collaboration is what made this engine the strongest chess engine in the world. We license our software using the GNU General Public License, Version 3 (GPL) with the intent to guarantee all chess enthusiasts the freedom to use, share and change all versions of the program.

Unfortunately, not everybody shares this vision of openness. We have come to realize that ChessBase concealed from their customers Stockfish as the true origin of key parts of their products (see also earlier blog posts by us and the joint Lichess, Leela Chess Zero, and Stockfish teams). Indeed, few customers know they obtained a modified version of Stockfish when they paid for Fat Fritz 2 or Houdini 6 - both Stockfish derivatives - and they thus have good reason to be upset. ChessBase repeatedly violated central obligations of the GPL, which ensures that the user of the software is informed of their rights. These rights are explicit in the license and include access to the corresponding sources, and the right to reproduce, modify and distribute GPLed programs royalty-free.

In the past four months, we, supported by a certified copyright and media law attorney in Germany, went through a long process to enforce our license. Even though we had our first successes, leading to a recall of the Fat Fritz 2 DVD and the termination of the sales of Houdini 6, we were unable to finalize our dispute out of court. Due to Chessbase’s repeated license violations, leading developers of Stockfish have terminated their GPL license with ChessBase permanently. However, ChessBase is ignoring the fact that they no longer have the right to distribute Stockfish, modified or unmodified, as part of their products.

Thus, to enforce the consequences of the license termination, we have filed a lawsuit. This lawsuit is broadly supported by the team of maintainers and developers of Stockfish. We believe we have the evidence, the financial means and the determination to bring this lawsuit to a successful end. We will provide an update to this statement once significant progress has been made.

We would like to thank our fans for their support, and encourage them to download and use the official version of Stockfish that we enjoy developing and sharing freely.

The Stockfish team