Houdini is a UCI chess engine developed by Belgian programmer Robert Houdart. It is influenced by open source engines IPPOLIT/RobboLito, Stockfish, and Crafty. Earlier versions are free for non-commercial use (up to version 1.5a), but later versions (2.0 and onwards) are commercial. As of January 2017, Houdini 5 is the second top-rated chess engines on major chess engine rating lists between Stockfish and Komodo.[1][2][3][4][5]
Playing style
Chess commentator and video annotator CM Tryfon Gavriel compared Houdini's playing style to that of the Romantic Era of chess, where an attacking, sacrificial style was predominant.[6]
Version history
| Version
|
Release date
|
Features[7]
|
| 1.0
|
May 15, 2010 (2010-05-15)
|
First release
|
| 1.01
|
June 1, 2010 (2010-06-01)
|
Bug fixes, improved search algorithm
|
| 1.02
|
June 18, 2010 (2010-06-18)
|
SMP and hash collision bug fixes. Work-around for Shredder GUI.
|
| 1.03
|
July 15, 2010 (2010-07-15)
|
Multi-PV, searchmove and large page support. Improved evaluation function.
|
| 1.03a
|
July 17, 2010 (2010-07-17)
|
Bug fix for Multi-PV
|
| 1.5
|
December 15, 2010 (2010-12-15)
|
Improved search and evaluation. Gaviota Table Base Support.
|
| 1.5a
|
January 15, 2011 (2011-01-15)
|
Maintenance update with work-arounds for Fritz GUI and other minor improvements.
|
| 2.0
|
September 1, 2011 (2011-09-01)
|
First commercial release. Improved analysis capabilities, enhanced search and evaluation. Houdini Pro version for high-end users with powerful hardware (multi-core support). Chess960 support. Strength limit feature. Position learning. Save hash to file, load hash from file, never clear hash.
|
| 2.0b
|
November 7, 2011 (2011-11-07)
|
Maintenance update with minor bug corrections and Nalimov EGTB support.
|
| 2.0c
|
November 20, 2011 (2011-11-20)
|
Maintenance update with minor bug corrections and new analysis options. MultiPV_cp option to limit multi-PV analysis to moves within a range of the best move. FiftyMoveDistance option to make the 50-move rule kick in earlier. UCI_Elo and UCI_LimitStrength options as UCI standard-compliant alternative to Strength option. Exit on detection with GUI exit.
|
| 3.0
|
October 15, 2012 (2012-10-15)
|
Major new version. Improved search and evaluation (+50 Elo), Tactical Mode, Scorpio bitbases, accelerated Principal Variation Search "Smart Fail-High", optimized hash usage.
|
| 4.0
|
November 25, 2013 (2013-11-25)
|
Major new version. Improved search and evaluation (+50 Elo), 6-men Syzygy table bases (coding provided by Ronald de Man)
|
| 5.0
|
November 7, 2016 (2016-11-07)
|
Major new version, about 200 Elo stronger. Rewritten evaluation function, deeper search.
|
| 5.01
|
November 15, 2016 (2016-11-15)
|
Maintenance update with some interface corrections and improvements.
|
| 6.0
|
September 15, 2017 (2017-09-15)
|
Major new version. Improved search and evaluation (+50-60 Elo), enhanced multi-threading.
|
| 6.01
|
September 24, 2017 (2017-09-24)
|
Maintenance update with Nalimov EGTB correction and new output option.
|
| 6.02
|
October 1, 2017 (2017-10-01)
|
Maintenance update with Polyglot book support.
|
The latest stable release of Houdini comes in two versions: Houdini 6 Standard and Houdini 6 Pro. Houdini 6 Pro supports up to 128 processor cores, 128 GB of RAM (hash) and is NUMA-aware, Houdini 5 Standard only supports up to 8 processor cores, 4 GB of hash and is not NUMA-aware. As with many other UCI engines, Houdini comes with no GUI, so a chess GUI is needed for running the engine. Houdini 5 uses calibrated evaluations in which engine scores correlate directly with the win expectancy in the position.[7]
Competition results
Houdini has won top honours in the TCEC tournament, which is often regarded as the Unofficial World Computer Chess Championship. Houdini has won three seasons to date, and narrowly failed to qualify for the finals in nTCEC Season 2, having lost out to Komodo and Stockfish.[8]
Notable games
"Houdini Immortal"
Rybka - Houdini
| a | b | c | d | e | f | g | h | |
| 8 | | 8 |
| 7 | 7 |
| 6 | 6 |
| 5 | 5 |
| 4 | 4 |
| 3 | 3 |
| 2 | 2 |
| 1 | 1 |
| a | b | c | d | e | f | g | h | |
Position after the 24th move. Houdini (Black) is three pawns down but has very active pieces and White's king is exposed. White couldn't avoid to lose a piece 7 moves later.
