Stockfish Leads 8 Engines In Computer Chess Championship Stage 2; Lc0 A Contender

The first stage of the first Computer Chess Championship event is in the books, and after 562 official games Stockfish tops the leaderboard with an excellent score of 39/46, the first of eight engines to advance to stage two.

The two other big-name engines, Komodo (38/46) and Houdini (37/46), are just below Stockfish at the end of the stage one, with a large gap between those three and the next five engines in the standings.

The machine-learning chess project Lc0 (“Leela“) finished in a solid fifth place with 32.5/46, good enough to advance to the next round as the neural-network engine wows fans with its intuitive and energetic play.

Created just eight months ago, Lc0 has improved rapidly enough to stake a claim as one of the world’s top five chess engines—and it’s not done gaining strength.

The Fire chess engine was in fourth place as stage one closed, nipping Lc0 by a half-point on 33/46. Ethereal, Booot and Andscacs round out the top eight to advance.

Stage one standings:

The top eight engines advance to CCCC 1: Rapid Rumble stage two.

The top eight engines advance to stage two of the tournament. 

Stage two:

Those eight engines will now battle in an intensive, 280-game stage as each engine plays every other five times as White and five times as Black in stage two. The top two finishers of stage two will play each other in a 200-game superfinal. Stage two is underway now at and 

Visit the main CCCC page for interactive features in the groundbreaking UI, or go to Twitch if you want to relax with some music generated by artificial intelligence. Both sites feature the same chat room (which is likely overflowing with Leela hype as you read this). 

Stage two of the Rapid Rumble is expected to last about a week before the two top engines emerge to play a weeklong superfinal. In stage two, the engines begin each pairing with a random, four-ply (two-move) opening book. In the next game between the two engines, the colors are reversed and the same line is played.

The four-ply lines are chosen randomly from a set of 354 openings that CCCC developers deemed “reasonably balanced.” The miniature opening books provide variety of play and interesting positions likely never-before-played at such a high level of strength. 

Games of stage one:

Computer chess fans can now download the entire 569-game PGN from stage one, which includes the 552 official games counted for the standings and 17 more that were affected by technical issues. 

Download full PGN CCCC 1: Rapid Rumble | Stage 1

What was the best game of stage one? Many Leela fans would choose Lc0’s demolition of the Crafty engine from late in the stage. Leela’s early Rxg7 sacrifice was both beautiful and pragmatic.

Lc0-Crafty is a candidate for game of the tournament. Do you have a different choice for best game? Post it in the comments.

CCC 2: blitz also announced this week that the second CCC event, due to start in early October, will be at a blitz time control of five minutes per game plus two-second increment

Stage one prediction contest:

The five members who predicted the most accurate round-robin standings for stage one were rewarded with membership prizes.

The member @supercell45678 topped the contest standings with nine correct picks, including four of the top five. Accuracy in the top five was used as the first tiebreaker. For the win, @supercell45678 received three years of diamond membership.

The members @Karavadgooo and @Cardhu32 shared second-third place with nine correct picks and three of the top five. They each received one year of diamond membership. 

Members @pourya7 and @weski shared fourth-fifth with nine correct picks and one of the top five. They received three months each of diamond membership. 

Follow the Computer Chess Championship 24 hours a day at to watch your favorite engines and chat with computer chess fans.

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