Houdini (chess)

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 October 2015, Houdini 4 is the third top-rated chess engines on major chess engine rating lists after 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

The latest stable release of Houdini comes in two versions: Houdini 5 Standard and Houdini 5 Pro. Houdini 5 Pro supports up to 128 processor cores, 128 GB of RAM (hash) and is NUMA-aware, Houdini 5 Standard only supports up to 6 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]

Controversial origins

Robert Houdart describes his engine as original and admits taking ideas from the open source programs IPPOLIT/Robbolito, Stockfish and Crafty.^[8][9] However, some chess programmers raised suspicions that Houdart may have taken ideas from the controversial Ippolit/Robbolito source-code "too literally" as the initial base of his program.^[8][10]

Competition results

Houdini has won top honors 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.^[11]

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.

• TCEC Houdini - Rybka Match 2011 · Sicilian Defense: Alapin Variation. Stoltz Attack Ivanchuk Line (B22) · 0–1 Houdini sacrifices three pawns for piece activity and defeats the reigning computer chess champion Rybka in this game, popularly dubbed as the "Houdini Immortal".^[12][13]
• TCEC Houdini - Rybka Match 2011 · Spanish Game: Closed Variations (C84) · 0–1^[14]
• TCEC Houdini - Rybka Match 2011 · Queen Pawn Game: London System (D02) · 1–0 Houdini plays a pawn sacrifice on move 43.^[15]

References

External links

• Official website
• Interview with Houdart about the genesis and strengths of his program