Computer Chess Championship: 'Big 4' Engines Make Rapid Finals
Stockfish is a big favorite to take home another Computer Chess Championship.

Computer Chess Championship: 'Big 4' Engines Make Rapid Finals

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The four engines that have dominated the Computer Chess Championship since its inception will battle once again in the finals of CCC 3: Rapid Redux. 

CCC 3: Rapid Redux finals are now live:

Stockfish, Houdini, Komodo, and the machine-learning chess project Lc0 played their way through to the finals after 72 rounds in the stage-two round robin. Seven engines finished that stage after Komodo Monte Carlo was removed from the tournament for technical difficulties.

Stockfish, which has dominated all computer chess competitions not containing AlphaZero in the past few years, was once again atop the leaderboard with an undefeated 51/72. Houdini paced the chase group at 43 points, and Komodo was just behind at 41.5. The neural-network engine Lc0 held onto fourth place, 1.5 points ahead of Ethereal, which missed the cut.

Full standings from stage two are below. Click on the image for a larger version.

CCC 3 standingsStockfish led the "big 4" engines after stage two of the Rapid Redux.

The four engines will now play a grueling 48x round-robin to determine the Rapid Redux champion. The finals are already in progress, and the time control remains 30 minutes plus a five-second increment. You can watch the finals 24 hours a day at

Full specifications for the Rapid Redux finals:

  • Round robin
  • Top four engines from stage two
  • 48xRR: Each engine plays every other engine 48 times (24 as White, 24 as Black)
  • 288 games
  • Ponder: off
  • Opening book: six-ply book selected from top master and popular games; all openings chosen by tournament staff
  • Openings reversed the second time each engine plays each other.
  • Expected duration: 14 days computer chess championship

Stage two sample games and PGN:

It's hard to win as Black in the top echelons of computer chess. Of the 252 games in Rapid Redux stage two, Black scored the full point just 20 times.

In this game, Stockfish showed its class vs top-notch competition as it outmaneuvered Ethereal in a closed Sicilian. Stockfish wasn't afraid to bring its king to the sixth rank even with every piece still on the board, and this aggressive positional play paid dividends for the champion sea monster. 

It's also difficult to win a game quickly in computer chess, especially when the engines are set to play till checkmate.

In this short game, Houdini made Lc0's chances disappear in an instant after building up a truly terrifying pawn center.  

You can download the full PGN of all stage two games here.

CCC 3: Rapid Redux finals viewing options:

Can any engine give Stockfish a challenge in this format? Let us know what you think in the comments.

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