The powerful, open-source chess engine Stockfish narrowly beat out two strong commercial engines to win the first Chess.com Computer Chess Championship this week.

Stockfish placed clear first in the 10-engine round robin to reach the superfinal, and then edged the second-place Houdini in the rapid, blitz, and bullet finals to win the championship, which was shown on Chess.com's live server Nov. 13 through 16.

The Chess.com Computer Chess Championship was announced in September and featured the 10 strongest chess engines in the world. Three days of round-robin rapid play determined the top two engines, who faced off in a thrilling superfinal for the title.

All four days of the championship were covered live on Twitch.tv/chess and Chess.com/TV, with master commentary by IM Daniel Rensch and GM Robert Hess, making it the first computer tournament to be broadcast in real time with professional production and live announcers. Full video replays of all four days of coverage can be watched in the Twitch archives.

The aim of the tournament was to showcase the strength and beauty of computer chess in a viewer-friendly, rapid and blitz tournament so that the audience could follow along in real time.

That said, there was some serious computer science behind the event, as each engine played from a powerful Amazon Web Services computer. For more technical details on the engine and hardware configuration, see the announcement article.

One major facet of the tournament format was that there were no opening books, forcing each engine to independently make every one of its moves. The engines were strong enough to derive some serious opening theory on the fly, with most games following solid and established opening lines.

According to Norm Schmidt, Chess.com's technical advisor for the tournament, here is the breakdown of openings "chosen" by the engines and the results of the games.

French Defense = 44 games, 7 white wins, 28 draws, 9 black wins

Queens Pawn/Gambit = 30 games, 14 white wins, 11 draws, 5 black wins

Queen's Indian Defense = 11 games, 3 white wins, 6 draws, 2 black wins

Ruy Lopez = 6 games, 2 white wins, 4 draws, 0 black wins

Caro–Kann Defense = 5 games, 0 white wins, 4 draws, 1 black win

Sicilian = 4 games, 0 white wins, 3 draws, 1 black win

Although the world's top 10 engines were slotted into the tournament, most of the attention was on the "big three" engines of Stockfish, Komodo, and Houdini, universally considered the three strongest engines of all time.

The three engines battled fiercely in the round robin, with Houdini needing a brilliant win in the last round to clinch its spot in the superfinal.

Round Robin Final Standings

Round Robin Crosstable

# Name Rtg Perf 1 2 3 4 5 6 7 8 9 0 Pts SB 1 Stockfish 051117 3400 3526 01 ½½ ½1 ½1 11 11 11 11 ½1 14.5/18 2 Houdini 6.02 3407 3444 10 ½½ ½½ 1½ 1½ 11 1½ 1½ 11 13.0/18 3 Komodo 1959.00b 3398 3422 ½½ ½½ ½1 ½½ ½1 ½½ 11 11 1½ 12.5/18 4 Fire 6.2 3300 3389 ½0 ½½ ½0 ½½ 1½ ½1 1½ 11 11 11.5/18 5 Andscacs 0.92 3240 3258 ½0 0½ ½½ ½½ ½½ ½½ ½½ ½½ ½½ 8.0/18 6 Fizbo 1.9 3262 3237 00 0½ ½0 0½ ½½ ½½ ½½ 11 ½½ 7.5/18 55.00 7 Deep Shredder 13 3291 3234 00 00 ½½ ½0 ½½ ½½ 11 ½½ ½½ 7.5/18 54.75 8 Chiron 4 3203 3159 00 0½ 00 0½ ½½ ½½ 00 ½0 11 5.5/18 39.50 9 Booot 6.2 3224 3157 00 0½ 00 00 ½½ 00 ½½ ½1 1½ 5.5/18 37.00 10 Gull 3 syz 3191 3112 ½0 00 0½ 00 ½½ ½½ ½½ 00 0½ 4.5/18

The dominant performances by Stockfish and Houdini in the rapid round robin led to a superb matchup in the superfinal, with its unique format of five time controls, counting down from rapid to blitz and finally to bullet chess.

The superfinal itself came down to the very last set of games, as Stockfish took a one-point lead into the set of four bullet games. Two of those four games were decisive, with Houdini and Stockfish each notching exciting wins, allowing Stockfish to take the title.

Superfinal Crosstable

# Name Rtg Perf 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1 Stockfish 051117 3400 3424 ½ ½ ½ ½ 1 0 ½ ½ ½ 1 ½ ½ ½ ½ ½ ½ 0 ½ 1 ½ 2 Houdini 6.02 3407 3383 ½ ½ ½ ½ 0 1 ½ ½ ½ 0 ½ ½ ½ ½ ½ ½ 1 ½ 0 ½

The tournament featured $2,500 in prize money to further the development of computer chess.

1. Stockfish: $1,000

2. Houdini: $750

3. Komodo: $500

4. Fire: $250

Norm Schmidt, the developer of Fire, also served as Chess.com's technical advisor for the Computer Chess Championship. Schmidt will not accept the $250 prize money, which will instead be donated to charity.

There were 110 total games played in the championship, 90 in the round-robin stage and 20 in the superfinal.

The full set of tournament games can be downloaded by clicking the button below.

Download Tournament PGN

The Chess.com journalist Peter Doggers annotated three important and thematic games, each featuring one of the big three engines of Stockfish, Houdini, and Komodo.

Chiron vs Komodo, Round 6, 15/2 Time Control:

Houdini vs Booot, Round 9, 15/2 Time Control:

Stockfish vs Houdini, Superfinal, 10/2 Time Control: