

I can't find anything in the code that says otherwise. It certainly looks like the Houdini source code. It would've taken even the best talent months (or years?) of hard work to develop it, so it doesn't look like a prank. It was not a clone of Stockfish in the sense that the codebase was quite different, certainly not a 10 minutes copy-and-paste. I took a quick look into it, it looked like a valid strong chess engine. The alleged source code might have been published online. The main reason it looks different is because of the Dutch translation and the fact that Stockfish has evolved significantly since Houdart last touched the Stockfish codebase. In other words, Houdini did not notably build upon Stockfish in any meaningful way. (Source: nextchessmove's elo data + CCRL data) Later, when Houdini 6 was released, this was also true. However, the code came from TurboPack and was translated into C++, so it's not clear that that was original work, either.Īdjusting for the time of release, the version of Stockfish on GitHub at the time of Houdini 5's release was more or less equal in strength to Houdini 5. For example, the licensing system was not from Stockfish. In fact, in one file, evaluatie.cpp, you can spot the naming conventions used by the Hex-Rays decompiler.

There were changes, but Mark Lefler, developer of Komodo, noted that a number ofaa changes were simply adding features reverse engineered from Komodo. The leaked source code was compiled by Ed Schroder and found to have a 1:1 correspondence with Houdini in a vast number of test positions, while others, like Simon Guenther, have found that the leaked code behaves identically in the start position even up to high depths. The alleged performance improvements over Stockfish go away after removing this trick. Exploiting modular arithmetic tricks and archived Houdini games, this exact code was shown to be present in the release version of Houdini. To hide its origins, code was included that multiplied the node count by 8/7. A number of Stockfish developers, including former maintainers, have noted as such. The search, evaluation, etc., are almost identical to Stockfish, with the notable exception of being rewritten in Dutch.
