Breaking: Leela Chess Zero enters TCEC Season 12

LCZLeela Chess Zero (LC0), often called the open source Alpha Zero, is the first neural network chess engine to enter the Top Chess Engine Championship (TCEC). This will happen in Season 12, that starts this April 19th at 19:00 CET. Follow the games on the official website

Leela Chess Zero is an open source project by large community of programmers, with the goal to build a strong UCT chess AI following the same type of techniques as AlphaZero, as described in Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm i.e. follow in the steps of Alpha Zero by using the contributions of the computer chess community. Leela Chess Zero uses Stockfish’s position representation and move generation although no heuristics or prior knowledge are carried over from Stockfish.

Leela Chess Zero is going to play in TCEC Season 12, starting from Division 4. The entry is possible due to Defenchess (Div 3) withdrawing in the last moment. This makes ChessBrainVB automatic Division 3 participant and frees a place for LC0 to enter the competition.

More about TCEC S12: Official website / Twitch video channel / Full list of participants

Test match of LC0 vs a TCEC engine

Leela Chess Zero is a rapidly developing project. With every version released the strength of the engine increases. But is it ready for TCEC and the division structure of the championship, running only on CPU and observing the TCEC rules set? TCEC is build entirely for active projects of ELO strength of 3000 or more. To prove that LC0 is ready for the event it was pitted against older versions of two of the Division 4 engines in the field and a classical engine.

Against Scorpio, LC0 achieved +4=3-13 (5.5 points) and a performance rating of ~2700 ELO. Among the wins of LC0 was a fantastic miniature on the black side of Caro-Kann Tartakower with 6.c3, a 36 moves win with white in Spanish: Closed, Smyslov, 12.Nf1 Bb7, and a win in King’s Indian: Fianchetto, Classical, 9.h3 Qb6 10.c5 See the full list of games of the Scorpio – LC0 match.

In a mini match against Fruit, Leela Chess Zero was more than convincing with +4 = 1 -1 and a performance of over 3000 ELO. Against the classical version of Stockfish 1.0, Leela Chess Zero achieved +7=3-10

The version of Leela Chess in TCEC

The version of Leela Chess Zero that will participate in TCEC is LC0 ID 125. This is the same version that played the test matches vs Scorpio and Fruit. For more about LC0, meet the experts and contributors in the TCEC chat

Leela Chess Zero will run entirely on CPU during TCEC Season 12. There are plans to make a match between a higher level engine and Leela Chess Zero on GPU/TPU, however, that entirely depends on the support of the community

More about Leela Chess Zero in TCEC

Zero means no human knowledge added. This is the key difference between the NN engines and the standard chess engines. This will not be entirely true for the TCEC version of LC0. Tests have shown that it performs much better with tablebases. Such are used in the other engines in the field and it is most fair to have LC0 with tablebases as well. A LC0 + Syzygy tablebases shows a gain of over 300 ELO and this version will be used in TCEC S12.

The project requires a huge amount of computations and the only way for LC0 to advance is as distributed project. If you want to help the engine develop, please visit https://groups.google.com/forum/#!forum/lczero or the Leela Chess wiki