Houdini Chess Engine

Welcome to the Houdini Chess Engine home page. Houdini is a state-of-the-art chess engine for Windows combining outstanding positional evaluation with the most sophisticated search algorithm.

The name Houdini was chosen because of the engine's positional style, its tenacity in difficult positions and its ability to defend stubbornly and escape with a draw – sometimes by the narrowest of margins. On the other hand Houdini will often use razor-sharp tactics to deny its opponents escape routes when it has the better position.

At the time of writing Houdini leads all the major Computer Chess rating lists and is widely considered to be the strongest chess engine on the planet. From numerous interviews it appears that many top Grand Masters including the current chess World Champion Viswanathan Anand use and appreciate Houdini.

The Chess Club Live Facebook page phrased it like this: "If there ever was a computer descendant of the romantic players like Morphy, Anderssen, Spielmann, Marshall, Bogoljubow, Tal, Nezhmetdinov, Shirov, Morozevich it would be Houdini. Houdini is the current World number 1 chess engine and plays in a very romantic style."

Houdini 3: The Best Got Even Better!

The new Houdini 3 contains many evaluation and search improvements in all phases of the game and is about 50 Elo stronger than its predecessor Houdini 2. The opening improvements are mostly related to piece activity and space management and are convincingly demonstrated by the progress in Fischer Random Chess for which Houdini 3 has become about 75 Elo stronger. In the middle game Houdini 3 has significant enhancements for recognizing pieces with limited mobility and in king-side safety. In end games Houdini 3 will seek deeper and solve more positions than before.

Three Long Time Control Challenges

As a serious challenge for the new Houdini 3, last month three long matches between the Houdini 3 Beta version and other top engines (Houdini 2.0c, Stockfish 2.3.1 and Komodo 5) were played. Each match consisted of 120 games at 90 min + 30 sec/move, starting from 60 Noomen opening positions played from both sides.

Over-all result: Houdini 3 scored 62% (Perf: +81 Elo ± 24 Elo) against the average of Houdini 2.0c, Komodo 5 and Stockfish 2.3.1.

Download all the Games

The final Houdini 3 Release version is even slightly stronger than the Beta version used in these matches.

In the new Tactical Mode Houdini 3 will adapt its search strategy to prefer tactical solutions rather than positional moves in the root position. Some clever search tricks transform the engine into the most proficient tactical position solver ever. In tactical test suites the Tactical Mode will find more solutions and provide significantly faster solution times.

The Accelerated Principal Variation Search or “Smart Fail-High” is especially useful in very deep analysis when a different move becomes best at very high search depth. Houdini 3 will apply an automatic depth reduction that often speeds up finding the Principal Variation by a factor of 5 to 10.

Besides Nalimov and Gaviota End Game Table Bases, Houdini 3 now also supports Scorpio bitbases. These bitbases are loaded in memory when the program starts (requiring about 300 MB of memory) and are then readily available to the engine.

Hash usage has been optimized, improving back-tracking analysis. Houdini 3 Pro will now support hash tables up to 256 GB.

The engine evaluations have been carefully recalibrated so that +1.00 pawn advantage gives a 80% chance of winning the game against an equal opponent at blitz time control. At +2.00 the engine will win 95% of the time, and at +3.00 about 99% of the time. If the advantage is +0.50, expect to win nearly 50% of the time.

Fun fact: Over 10 million chess games were played for the development and tuning of Houdini 3!

Houdini 3 Download Versions for Windows

Houdini is written for Windows and will run on any not too ancient Windows version. On Linux you can run Houdini using Wine without any significant performance loss.

Two Houdini 3 download-only versions are available:

Houdini 3 Standard
€39.95 +VAT^*

Best buy for most users with main-stream hardware.
Supports up to 6 cores and 4 GB of hash.

Houdini 3 Pro
€59.95 +VAT^*

For high-end users with powerful hardware. Supports up to 32 cores and 256 GB of hash memory and NUMA-architecture. Click here for more information about Houdini Pro.

^*21% VAT will be added for customers from EU member states.

The Houdini 3 download link and serial number will be sent to you by e-mail within 24 hours of purchase. Note that during installation you'll require an internet access to activate the product.

If you haven't received our purchase confirmation mail within 24 hours, check your spam folder first, and if the mail is not there please contact us immediately via the support e-mail address [email protected].

Purchasing Houdini 3 will entitle you to all updates and corrections made to Houdini 3, direct e-mail support by the Houdini author and discounts to future versions of Houdini.

Too expensive? You can still download the free Houdini 1.5 which at the time of the Houdini 3 release remains unmatched in strength by any other chess engine.

Support

Direct support by the author of Houdini, Robert Houdart, is available by e-mail at the address [email protected].

Version History

Acknowledgements

An invaluable resource for any chess engine author is the excellent Chess Programming Wiki.

Without many ideas and techniques from the open source chess engines Ippolit and Stockfish, Houdini would not nearly be as strong as it is now.

The Gaviota EGTB probing code used by Houdini is © Miguel A. Ballicora, the Nalimov EGTB probing code is © Eugene Nalimov and the Scorpio bitbase probing code is © Daniel Shawul.

The Houdini 3 development was greatly aided by the kind support of Mr. Ahmed Mansoor.