Thoresen Chess Engines Competition

Promotional poster for Season 6 of TCEC

Thoresen Chess Engines Competition (TCEC or nTCEC) is a computer chess tournament organized, directed, and hosted by Martin Thoresen. TCEC is often regarded as the Unofficial World Computer Chess Championship because of its strong participant line-up and long time control matches on high-end hardware, giving rise to very high-class chess.^[1][2] The current champion is Komodo, having defeated Stockfish in December, 2014.

The first TCEC was in 2010. After a short break in 2012,^[3] TCEC was restarted in early 2013 (as nTCEC)^[4] and is currently active (renamed as TCEC in early 2014) with all-day live broadcasts of chess matches on its website. Supported by original engine authors and based on voluntarism and donation, it caused a furor in February 2011, when the free version of Houdini defeated reigning computer chess champion Rybka in a 40-game match.^[5][6][7] The current season of TCEC is sponsored by Chessdom Arena.^[8][9]

Overview

The TCEC competition is divided into Seasons, where each Season happens over a course of a few months, with matches played round-the-clock and broadcast live over the internet. Each season is divided into 4 qualifying stages and 1 Superfinal, where the top two chess engines battle it out over a series of 64 games to win the title of TCEC Grand Champion.

The time control in all events is 120+30 (120 minutes + 30 seconds added per move for the whole game) and pondering is set to off. The Opening Book is taken from recent strong human Grandmaster tournaments, is truncated to the first 6 or 8 moves, and is changed in every Stage. Engines are allowed updates between stages, unless there is a critical play-limiting bug, in which case the engine are allowed to be updated once during the stage. TCEC generates its own elo rating list from the matches played during the tournament. An initial rating is given to any new participant based on its rating in other chess engine rating lists.

There is no definite criteria for entering into the competition, other than inviting the top participants from various rating lists. The list of participants is personally chosen by Thoresen before the start of any new season. Usually chess engines that support multiprocessor mode are preferred (8-cores or higher). Both Winboard and UCI engines are supported. Large pages are disabled but access to various endgame tablebases is permitted.

¹ Rules may differ from season to season

GUI adjudication rule

A game can be drawn by threefold repetition or fifty-move rule. However, a game can also be drawn at move 40 or later if the eval from both playing engines are within +0.05 to -0.05 pawns for the last five moves, or ten plies. If there is a pawn advance, or a capture by any kind, this special draw rule resets and starts over. On the website, this rule shows as "Distance in plies to TCEC draw rule". It adjudicates as won for one side if both playing engines have an eval of at least 6.50 pawns (or -6.50 in case of a black win) for four consecutive moves, or eight plies - this rule is in effect as soon as the game starts. On the website, this rule shows as "Distance in plies to TCEC win rule". The GUI also adjudicates tablebase endgame positions (with 5-men or less) automatically.

Technical specifications

 The TCEC Computer:
 CPUs: 2 x 8 core Intel Xeon E5-2689 @ 3300 MHz
 CPU Coolers: 2 x Corsair H80i
 Motherboard: Asus Z9PE-D8 WS
 RAM: 64 GB Kingston KVR16R11D4K4/32 Reg/ECC
 PSU: Corsair AX 760
 SSDs: 2 x Samsung 840 Pro 128 GB @ Raid 0
 Case: Silverstone Raven RV03B-WA

 Configuration:
 Graphical User Interface (GUI): cutechess-cli (custom)
 Protocol: Winboard, UCI
 Large Pages: OFF
 Number of Cores/Threads (per engine): 8 or 16
 Split Depth: DEFAULT
 Main Hash Size: 16 GB (Maximum)
 Minor Hash Size: 1 GB
 Engine Opening Book: OFF
 Endgame Tablebases: 6-men Syzygy, 5-men Nalimov, 5-men Gaviota (cp2), 
   5-men Shredderbases and 5-men Robbobases (Totalbases + Triplebases) supported
 Tablebase Cache: 1024 MB (Maximum)
 Ponder/Permanent Brain: OFF
 Contempt/Draw Score: DEFAULT

N.B.: tablebases were disabled for all engines for the whole of Season 7 ^[10]

Tournament results

¹ Originally named "nTCEC Season 1"

² Originally named "nTCEC Season 2"

³ Special Chess960 quad-round-robin tournament consisting of the top 8 engines from Season 6 that had support for Chess960

⁴ Season 7 did not use of endgame table bases. Stage two did not use opening books.

Notable games

Houdini vs Rybka, TCEC, 2011

	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

Here, Houdini has just played the pawn sacrifice 43. c6.^[6]

Equinox vs Protector, TCEC S4

	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

55...Rg4 left White in zugzwang.^[11]

Shredder vs Gull, TCEC S4

	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

Shredder (White) is on the brink of being checkmated, but found the defensive resource 46. Bb3 Nxb3 47. Qf4+ gxf4 48. Rb7+ Kc8 49. Rc7+ Kd8, etc. If Black captures the white rook, it is stalemate.^[12][13][14]

Stockfish vs Houdini, TCEC S5

	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

In this position, eight moves (16 ply) after Stockfish's evaluation began a steady climb, Houdini evaluated it at a meagerly +0.09 (while Stockfish saw +9.91). Only after 48. exd6 did Houdini see that Black is lost. Five moves later, the game was over.^[15]

Komodo vs Stockfish, TCEC S6

	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

Komodo plays the extraordinary move 17. Kd3, bringing the king into the center of the board in the midst of a complex tactical middlegame. Stockfish even expected 18. Ke4 on the next move, but unfortunately Komodo chose to play 18. f6 instead.^[16]

Pre-TCEC:

• Stockfish vs Houdini, Match 3, 23.1, "Game of the Month 1", 2010-07-27, 1–0^[17]
• Shredder vs Naum, Tournament 1, 1.3, "Game of the Month 2", 2010-08-01, 0–1^[18]
• Houdini vs Rybka, Tournament 5, 8.3, "Game of the Month 3" 2010-11-26, 1–0^[19]

Season 1-3:

• Rybka vs Houdini, TCEC S1, Elite Match, 1.1 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".^[5][20][21]
• Houdini vs Rybka, TCEC S1, Elite Match, 37.1, 1–0 Houdini plays a pawn sacrifice on move 43.^[6][22]
• Houdini vs Rybka, TCEC S2, Elite Match, 19.2, 1–0 Houdini exploits minor inaccuracies by Rybka with a sacrifice.^[23]

Season 4:

• Equinox vs Protector, TCEC S4, Stage 1, 3.7, 0–1 A zugzwang position is reached with almost all pawns and four rooks on the board.^[11]
• Gaviota vs Spike, TCEC S4, Stage 2a, 7.1, 1–0^[24]
• Houdini vs Junior, TCEC S4, Stage 2a, 7.2, 1–0^[25]
• Komodo vs Hannibal, TCEC S4, Stage 2b, 4.1, 1–0 Komodo sacrifices the exchange for positional gain.^[26]
• Shredder vs Gull, TCEC S4, Stage 2b, 14.3, ½–½ Shredder pulls off a save, at the brink of defeat.^[12][13][14]
• Stockfish vs Houdini, TCEC S4, Superfinal 48.1, 0–1^[27]

Season 5:

• Equinox vs Spike, TCEC S5, Stage 1, 6.5, 1–0 Equinox first sacrifices the exchange, and then a bishop.^[15]
• Bouquet vs Stockfish, TCEC S5, Stage 2, 2.1, 0–1 After a long waiting game, Stockfish sacs a pawn on move 66 and the exchange to open the game up.^[15]
• Tornado vs Critter, TCEC S5, Stage 2, 3.7, 0–1 Critter sacrifices two pawns and then a rook to build up a strong attack.^[15]
• Junior vs Stockfish, TCEC S5, Stage 2 15.7 1–0 Junior plays multiple sacrifices.^[15]
• Gull vs Komodo, TCEC S5, Stage 3, 2.2, 0–1^[15][28]
• Gull vs HIARCS, TCEC S5, Stage 3, 8.5, 0–1 HIARCS sacrifices a queen for three pieces.^[15]
• Naum vs Rybka, TCEC S5, Stage 3, 12.4, 1–0 After both engines evalutated the position as more than a pawn in blacks advantage the game very rapidly turns strongly to whites favor.^[15]
• Houdini vs Stockfish, TCEC S5, Stage 3, 17.4, 0–1 Stockfish, thanks to its heavy depth-oriented search, out-calculates Houdini, and wins the game.^[15][29]
• Stockfish vs Houdini, TCEC S5, Stage 4, 6.3, 1–0 At one point in this game, the difference between Stockfish's evaluation and Houdini's evaluation is almost 10.00 (1,000 centipawns), a rarity in high-level computer chess. Stockfish was able to outcalculate Houdini considerably and only after a couple of moves did Houdini realize what had happened.^[15]
• Komodo vs Houdini, TCEC S5, Stage 4, 27.2, ½–½ An imbalanced endgame, with KQPPP versus KRRN.^[15]
• Bouquet vs Komodo, TCEC S5, Stage 4, 29.3, 0–1 Komodo won a complicated endgame (KPRNBvKPQ), although it was unassisted by endgame tablebases.^[15]

Season 6:

• Komodo vs Stockfish, TCEC S6, Stage 3, 1, 1-0^[30]
• Stockfish vs Houdini, TCEC S6, Stage 4, 27, 1-0 Stockfish defeats Houdini in just 29 moves.
• Komodo vs Stockfish, TCEC S6, Superfinal, 4, 0-1 Stockfish plays an exchange sacrifice and then positionally outplays Komodo.
• Komodo vs Stockfish, TCEC S6, Superfinal, 18, 0-1 Stockfish defeats Komodo in just 33 moves in the Kings Indian Defense.
• Komodo vs Stockfish, TCEC S6, Superfinal, 20, ½–½ Komodo strays his king out to the center of the board in a sharp middlegame.

Season 7:

• Stockfish vs Jonny6, TCEC S7, Stage 2, 29, 1-0 Stockfish sacrifices both rooks for initiative and mobility and defeats Jonny.

References

Sources

• Thoresen, Martin (March 1, 2013). "nTCEC Complete Rules + FAQ". TCEC. Retrieved October 25, 2013.
• Perez-Franco, Roberto (January 15, 2014). "DIGITAL CHESS REVIEW: One chess champion per laptop". The Tech 133 (62). Retrieved February 2, 2014.

External links

• TCEC Live Games Page
• Thoresen Chess Engines Competition on Facebook
• TCEC Season Archive
• Additional information for Season 4
• Additional information for Season 5
• The Real Kings of Chess Are Computers