Houdini Chess Engine
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November 9, 2016: Houdini 5 has been released - Get it today!

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.

Each Houdini release since December 2010 has been leading the major computer chess rating lists and has been widely considered to be the strongest chess engine money can buy. From numerous interviews it appears that many top Grand Masters including chess World Champions 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."

Get the new Houdini 5 today!

Houdini 5: Rejuvenated and 200 Elo stronger!

Released nearly 3 years after the previous version, the eagerly anticipated Houdini 5 is a rejuvenated and vastly improved engine.

Houdini 5 is about 200 Elo stronger than its predecessor thanks to its completely rewritten positional evaluation function and many new techniques and ideas developed over the past three years. More aggressive King safety and sophisticated piece mobility are the keys to Houdini 5's unique playing style, combining aggressive ideas with sound positional judgment and plans.

By being more selective in its move choices, Houdini 5 now searches significantly deeper than before. This pays huge dividends in every stage of the game, but particularly in end games. For the best end game play, the new Houdini continues to support Syzygy end base tables, which can now be combined with the Nalimov tables to find the shortest path to mate.

The new Houdini implements the so-called "lazy SMP" algorithm and performs better than before on hardware with multiple processor cores. Up to 128 threads are now supported by the Houdini 5 Pro engine.

All major features of previous Houdini versions are still available: multi-PV analysis with user-definable evaluation threshold, Chess960 support and Persistent Hash (saving analysis results to a disk file for later reuse). The unique Tactical Mode has been updated and is now stronger than ever to find tactical solutions in positions.

A development version of Houdini 5 achieved a resounding victory with a score of 56/62 (50 wins and 12 draws) in the TCEC Season 9 Rapid tournament that featured the best 32 engines in the world. The final release version of Houdini 5 is about 30 Elo stronger than the engine that played in the TCEC tournament.

The on-line Houdini Chess Engine User's Manual provides clear and detailed instructions so that you can effortlessly leverage your chess analysis capabilities.

Houdini 5 Download Versions for Windows

Houdini is written for Windows and will run on any not too ancient Windows version. On Linux systems you can run Houdini using Wine without any significant performance loss. On Apple computers a Virtual Machine (e.g. Parallels Desktop) is required to run Houdini.

Two Houdini 5 download-only versions are available:
Houdini 5 Standard
€39.95 +VAT*
Best buy for most users with main-stream hardware.
Supports up to 6 cores and 4 GB of hash.
Houdini 5 Pro
€59.95 +VAT*
For high-end users with powerful hardware. Supports up to 128 cores and 128 GB of hash memory, Large Memory Pages, NUMA-architecture and Nalimov bases.
Click here for more information about Houdini Pro.
*VAT will be added for customers from EU member states.

The Houdini 5 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 5 will entitle you to all updates and corrections made to Houdini 5, 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 5 release remains one of the stronger free chess engines.

Support

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

Before mailing please check out the on-line Houdini Chess Engine User's Manual with installation tips and Frequently Asked Questions.

Version History

Houdini 5

  • Houdini 5.01 (20161115): Maintenance update with some interface corrections and improvements.
  • Houdini 5 (20161107): Major new version, about 200 Elo stronger. Rewritten evaluation function, deeper search.

Houdini 4

  • Houdini 4 (20131125): Major new version. Improved search and evaluation (+50 Elo), 6-men Syzygy table bases.

Houdini 3

  • Houdini 3 (20121015): Major new version. Improved search and evaluation (+50 Elo), Tactical Mode, Scorpio bitbases.

Houdini 2

  • Houdini 2.0c (20111120): Maintenance update with minor bug corrections and new analysis options.
  • Houdini 2.0b (20111007): Maintenance update with minor bug corrections and Nalimov EGTB support.
  • Houdini 2.00 (20110901): Improved analysis capabilities, enhanced search and evaluation.

Houdini 1.5

  • Houdini 1.5a (20110115): Maintenance update with work-arounds for Fritz GUI and other minor improvements.
  • Houdini 1.50 (20101215): Improved search and evaluation. Gaviota Table Base Support.

Houdini 1.0

  • Houdini 1.03a (20100717): Bug fix for Multi-PV.
  • Houdini 1.03 (20100715): Multi-PV, searchmove and large page support. Improved evaluation function.
  • Houdini 1.02 (20100618): SMP and hash collision bug fixes. Work-around for Shredder GUI.
  • Houdini 1.01 (20100601): Bug fixes. Improved search algorithm.
  • Houdini 1.00 (20100515): First release.

Acknowledgements

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

The Syzygy TB probing code used by Houdini is © Ronald de Man, the Nalimov EGTB probing code is © Eugene Nalimov.