Leela Chess Zero close to crossing the 3700 elo mark

Round 1 of TCEC Swiss 8 is now in the history books, with a second engine approaching 3700 elo mark. After Stockfish became the first engine to cross 3700 this month of April, now Leela Chess Zero is close to joining the 3700 elo club. Leela defeated Ethereal (elo 3617) with the score 1,5-0,5 in their TCEC Swiss 8 mini match. The current elo of Leela Chess Zero is 3699

Replay all the games of round 1 here

No engine achieves double victory in round 1

As per the rules, each round the opponents play the same opening once as white and once as black. A total of 15 engines won their mini matches in round 1. Yet, no engine achieved to win the mini match with a perfect 2,0/2 score. Here are the standings after the first round.

Patricia (3357) – 1.5
KomodoDragon (3620) – 1.5
Stockfish (3733) – 1.5
LCZero (3697) – 1.5
PlentyChess (3551) – 1.5
Starzix (3482) – 1.5
Weiss (3383) – 1.5
Velvet (3522) – 1.5
Berserk (3650) – 1.5
Obsidian (3644) – 1.5
Integral (3428) – 1.5
Ginkgo (3543) – 1.5
Stormphrax (3543) – 1.5
Tucano (3384) – 1.5
Texel (3380) – 1.5

sirius (3322) – 1
Booot (3454) – 1
BlackMarlin (3500) – 1
Uralochka (3540) – 1
STRO4K (2914) – 1
Reckless (3460) – 1
ScorpioNN (3411) – 1
rofChade (3578) – 1
Stoofvlees (3556) – 1
Horsie (3508) – 1
Viridithas (3578) – 1
Clover (3535) – 1
Renegade (3438) – 1
Stash (3344) – 1

Ethereal (3617) – 0.5
Lynx (3226) – 0.5
ice4 (3140) – 0.5
DeepSjeng (3451) – 0.5
Igel (3526) – 0.5
Minic (3456) – 0.5
Caissa (3598) – 0.5
Ceres (3628) – 0.5
Seer (3552) – 0.5
Revenge (3522) – 0.5
ChessFighter (3206) – 0.5
Altair (3439) – 0.5
Arasan (3481) – 0.5
RubiChess (3600) – 0.5
Princhess (3169) – 0.5

Top Chess Engine Championship (TCEC), the world’s premier championship for computer chess, is set to launch its new season with the highly anticipated TCEC Swiss 8 tournament on May 16, 2025, at 19:00 CEST. Featuring 44 of the world’s most advanced chess engines, this event is poised to surpass the record set by last season’s Swiss 7, cementing its status as the strongest chess championship ever. With a lineup of elite engines, cutting-edge hardware, and a global audience of chess enthusiasts, TCEC Swiss 8 promises to deliver a unique show 24/7 over the next months. Follow TCEC Swiss 8 live: Official website / TCEC Chess TV / Lichess / Chessdom live

Hardware boost for chess engines at TCEC aka Kittenware

With high confidence we can say that TCEC has the best hardware setup for chess ever, and you can enjoy it live during TCEC Season 28 and TCEC Swiss 8 thanks to the sponsorship of Kittenkaboodle.

Kanchess comments, “The brand new Kittenware truly belongs in TCEC as most serious top chess engine competition, and is an awesome donation! Can’t wait to see which engines will show how to use this monster hardware with two separate boxes more to their advantage and add some substantial elo” Aloril adds, “Best effort was truly done for both CPU and GPU engines by Kittenkaboodle.“

The GPU boost, benefiting NN engines is the following:

Current new hardware, sponsored by Kittenkaboodle: 8x RTX 5090 (32GB):

• Total memory: 256GB (32GB x 8).
• Total CUDA cores: ~174,080
• Total Tensor cores: ~5,440
• Total power consumption: ~3,600W (450W x 8)

Former hardware, sponsored by Noobpwnftw: 2x A100-PCIE-40GB:

• Total memory: 80GB (40GB x 2).
• Total CUDA cores: 13,824.
• Total Tensor cores: 864.
• Total power consumption: ~500W.

Traditional CPU engines will also enjoy a boost

Current new hardware, sponsored by Kittenkaboodle: AMD EPYC 9754 (2x):

• Type: Server-grade CPU, 4th Gen EPYC (Bergamo, Zen 4c, 5nm).
• Cores/Threads: 128 cores/256 threads per CPU, total 256 cores/512 threads.
• Clock Speed: 2.25 GHz base, 3.1 GHz boost (lower boost due to high core count).
• Cache: 256 MB L3 cache per CPU (512 MB total).
• Performance: ~180,000–200,000 PassMark score per CPU (estimated, ~360,000–400,000 total).

Former hardware, sponsored by Noobpwnftw: Intel Xeon 6230R (2x):

• Type: Server-grade CPU, 3rd Gen Scalable Xeon (Cascade Lake Refresh, 14nm).
• Cores/Threads: 26 cores/52 threads per CPU, total 52 cores/104 threads.
• Clock Speed: 2.1 GHz base, 4.0 GHz turbo.
• Cache: 35.75 MB L3 cache per CPU (71.5 MB total).
• Performance: ~40,000 PassMark score per CPU (estimated, ~80,000 total).

Participants and ELO records

In the three years period between Swiss 1 and Swiss 7, the average ELO of the top 10 participants has increased by 60 points. Now in under 12 months we see another increase of 60 points! In this TCEC Swiss 8 for the first time the chess world will see a 3700+ engine in action, in a top 10 field that exceeds 3621 average ELO!

Stockfish (Elo: 3728): The open-source juggernaut and reigning TCEC Grand Champion, Stockfish has dominated the last seasons, winning the Leagues, Fischer Random, and Cup events. It has just set an unseen rating record and is coming for the only title it lacked last season – the Swiss

LCZero (Elo: 3693): The neural network-based engine, built on the principles of AlphaZero, is coming to TCEC Swiss as defending champion, while aiming to cross the 3700 elo mark during the event

Berserk (Elo: 3646): A rising star in the computer chess world, Berserk has climbed the rankings with its aggressive play and robust performance, making one of the dark horses in Swiss 8.

Obsidian (Elo: 3637): Authored by Gabriele Lombardo who is still U18, Obsidian aims to get minimum a medal at Swiss 8

Ceres (Elo: 3624): A newcomer to the elite ranks in the past season, Ceres has impressed with its performance and is expected to challenge the established giants.

KomodoDragon (Elo: 3615): A veteran engine with TCEC titles in Seasons 5, 7, and 8, KomodoDragon remains a formidable competitor, despite not being actively updated. Once part of the big 3, now KomodoDragon is trying to stay among the best.

Ethereal (Elo: 3613): A consistent performer, Ethereal brings a balanced approach to the board, capable of upsetting higher-rated opponents, while gaining strength every season

Caissa (Elo: 3591): A newer engine that has shown promise in recent seasons, Caissa is poised to make waves in the computer chess world

RubiChess (Elo: 3591): With a solid track record, RubiChess is a reliable contender that can take valuable points from the favorites

Viridithas (Elo: 3570): A lesser-known but rapidly improving engine, Viridithas adds unpredictability to the mix with its unique playing style

Stay tuned for the full list of participants.

More about the Top Chess Engine Championship

TCEC seasons are divided into multiple events, including the traditional Leagues, a knockout Cup, a Fischer Random tournament, and the Swiss tournament.

Since its inception in 2010, TCEC has been the premier platform for pitting the world’s top chess engines against one another in long time-control matches on high-end hardware. Originally known as the Thoresen Chess Engines Competition, TCEC was founded by Martin Thoresen and has been organized by Chessdom since Season 7. The tournament’s reputation as the “Unofficial World Computer Chess Championship” stems from its rigorous format, elite participant lineup, and commitment to showcasing the highest level of computer chess.

Stockfish has played 260 games in the period with 61% score against opposition with average rating of 3625 ELO. That translates into a rating jump from 3672 to 3707 ELO, gained mainly during the events of TCEC Season 27 – Leagues, Cup, and Swiss. (replay TCEC S27 Superfinal here)

More about the ELO record of Stockfish and the upcoming TCEC S28 events at the Chessdom newsletter. This month of April, Chessdom is launching a newsletter that you get DAILY to your mailbox for FREE (signup in the box below)

The closest opponent to Stockfish is the Alpha Zero young sister Leela Chess Zero. It is currently second on the rating list with 3670 ELO. While 37 points are a solid distance in computer chess, Leela Chess Zero actually maintains the pace and stays in the race (see the graph below)

Third is Berserk with 3617 ELO, which briefly interrupted its development, but now is back with fresh power. The biggest danger for Stockfish might come from the 4th engine on the list – lurking from behind is Obsidian with 3612 ELO. This might be close to 100 ELO below the playing strength of the leader, but Obsidian is relatively new engine and is developed by the 16 years old (!!!) Gabriele Lombardo.

This graph shows the progress of Stockfish from the time around the year 2021 to today. It compares the engine to Leela Chess Zero, Stoofvlees, KomodoDragon, and clearly shows the rapid rise of Obsidian. Each Top Chess Engine Championship season is marked on top, with the graph spanning from TCEC Season 19 to TCEC Season 27.

How does Stockfish compare to Stockfish from the past

Stockfish 13 was released February 19, 2021. It is the engine used as a benchmark in the computer rating list. Stockfish 13, which was unbeatable monster back in 2021, currently sits at 17th position in the rating list with 3522 ELO. This is close to 200 ELO less than the current version of Stockfish in just four years!

Furthermore, engines like Clover, Stoofvlees, Seer, Rofchade, Viridithas, Rubichess, Caissa, Ethereal, KomodoDragon, Ceres, Obsidian, Berserk, and Leela Chess Zero all sit ahead of Stockfish 13 in this list, showing the rapid growth and development of the whole computer chess sector

At this moment we have 4KiB (4096 bytes) size engines with playing strength 3100+ (see it to believe it)

More about the Top Chess Engine Championship

The new season of the strongest computer chess championship, where Stockfish will defend its title and ELO record is about to start (Official website / TCEC Twitch TV)

Top Chess Engine Championship, or TCEC for short, is the premier computer chess tournament that has been running since 2010. The use of long time controls high-end hardware results in exceptionally high-quality chess games. The tournament pits the best chess engines – software programs designed to play chess – against each other to determine the strongest among them.

A Top Chess Engine Championship season is a multi-month event that features a series of competitions, typically lasting around 3-4 months, with matches played continuously 24/7 and broadcast live online at the official website. Each season is structured to include several distinct tournaments, testing the engines across various formats and conditions. As of the current format, a season contains:

1. Leagues Season: This is the core event where engines compete in a tiered league system. It starts with lower divisions (like a Qualification League) and progresses through higher divisions, culminating in the Premier Division. Engines move up or down based on their performance, with the top two from the Premier Division advancing to the TCEC Superfinal – a 100-game match to crown the “TCEC Grand Champion.”
2. Cup: A knockout-style tournament featuring 32 engines. It consists of five single-elimination rounds, offering a different competitive dynamic from the league format.
3. Swiss Tournament: A Swiss-system event where all participating engines (often 44 or more) play a set number of rounds (e.g., 11 rounds). Pairings are determined by performance, allowing for exciting matchups and opportunities for underdog engines to shine.
4. Fischer Random Chess (FRC) Tournament: A competition using Chess960 rules aka Fischer Random, lately called and branded as Freestyle chess by Magnus Carlsen, where the starting positions of pieces are randomized. It typically involves preliminary leagues, semifinals, and a final league, with the top two engines advancing to a Superfinal of 50 games.
5. 4k event – included in recent seasons, the TCEC 4k Event is a special competition within the Top Chess Engine Championship that challenges developers to create highly efficient chess engines with a strict size limit of 4 kilobytes (4KiB, or 4096 bytes). This constraint applies to the engine’s executable file or script, making it a unique test of programming skill, optimization, and creativity in computer chess. The idea is to see how strong a chess engine can be when stripped down to an extremely small footprint, harking back to the spirit of early computing challenges like those seen in demo competitions or even the minimalist systems used in the Apollo missions.

It could have been an 11-way tie for first, had Halogen and Leela split the points. However, Leela managed to outplay Halogen in a QGD Slav and jumped ahead of competition.

The standings bring exciting matchups in the next round , where we will see Leela Chess Zero – Stockfish and Ceres – RofChade

Follow TCEC live: Official website / TCEC Chess TV / Lichess / Chessdom live More: Interview with Gabriele Lombardo from Obsidian

Standings

1. Leela Chess Zero 4,5/6

2-10. Ethereal, Stockfish, Ceres, Ginkgo, rofChade, Stormphrax, Viridithas, Devre, and Stoofvlees 4,0/6

11-17. Halogen, Velvet, Berserk, Minic, Obsidian, Caissa and Igel 3,5/6

Total 44 engines, full standings here

See Obsidian in action now live at https://tcec-chess.com/

Obsidian is currently one of the top engines in the world. How did you decide to enter computer chess programming?

My interest in chess engines began about 2 years ago. I began playing chess with a friend OTB, and soon I found out about chess.com and began playing there. In chess.com the game review feature sparked my interest in chess engines because I was wondering, “How does this guy know what moves are good and bad?”. So I found out about chess engines and I worked for some months on a kind of “toy” engine. Then, I decided to rewrite everything from scratch in a more serious manner and that was what is now Obsidian.

The other day in chat someone mentioned that you are very young, actually the youngest of all developers in TCEC

That’s right. Every engine developer I have ever talked to is older than me. I am 16 years old and will turn 17 in March 2025.

The new season of Top Chess Engine Championship TCEC has started with Swiss 7, the strongest chess event regarding playing strength. What are your expectations?

Obsidian most recent versions defeated Komodo Dragon 3.3 (the latest version) on SP-CC and Ipmanchess (two leaderboards). I hope Obsidian can repeat this performance in the Top Chess Engine Championship. The number of games played on TCEC is limited, so bad luck could happen. Hopefully not!

What do you consider the biggest strength of Obsidian? And the biggest weakness?

The biggest strength of Obsidian is the evaluation. It is not a random Leela data NNUE – my NNUE is, by a big margin, stronger than the NNUE of any other Leela data engine, outside of Stockfish of course. Excluding the datagen process (which is missing), there is a lot of effort into training. It was speculated about 2 months ago by a Torch developer that Obsidian’s evaluation might be almost as strong as that of Torch.

The biggest weakness is probably the search algorithm, being the engine very fast in terms of nps.

What are the original inventions in Obsidian?

I don’t know if calling them “inventions” is appropriate. There are several original implementation details that gained Elo in my engine in comparison to the way I’ve seen other engines do things. They are very technical and specific things I won’t go over.

Regarding speed, Obsidian until recently had 2 completely original techniques about efficient updates of the neural network. Recently I had to remove them due to their high RAM consumption – but they were significant speedups.

Lastly, I don’t do datagen, but in the training process itself I use various techniques that result in a (far) stronger evaluation than that of engines with similar training data.

What are the things that you are currently researching?

In this period I am trying to introduce 3 hidden layers (instead of 1) in the neural network evaluation of Obsidian. Every attempt until now has been a failure. I can successfully measure an increased strength of evaluation, but the speed loss is exaggerate.

Does Obsidian have plans to pull away from using Leela data for NNUE towards a more original approach?

Generating data by myself would be impossible for now, due to my very restricted amount of resources/hardware. I don’t think I could find someone else who would dedicate to generate data for Obsidian either.

Make a prediction for top 5 in the current TCEC Swiss 7

My prediction is: Stockfish, LCZero, Ceres, Berserk, Obsidian

Do you follow human chess games? Are you going to follow the Chess Olympiad in Budapest?

I watch human games sometimes. I mostly follow Hikaru, and last week I’ve been watching the Speed Chess Championship. I didn’t know about the chess Olympiad in Budapest until I read your message – I will probably watch some games.

TCEC Swiss 7 will be the first event of the season and will be the strongest chess event (ever!). A total of 44 participants, including the Swiss 6 champion LcZero, the top rated Stockfish and exciting newcomers Ceres, PlentyChess, and Patricia, will battle it out for the title in this record breaking Swiss.

Swiss 7 will be daily live on the official website of TCEC, in video format on TCEC Twitch TV, a broadcast on our favorite game server Lichess, and news reports on Chessdom.

Breaking the ELO record

ELO records depend on multiple factors. They include, but are not limited to, the formula used, the field, the sample size (number of games), and even the configuration (when talking about computer chess). Luckily, TCEC has the precise measurements to detect rating jumps in chess software. And the jump in Swiss 7 is huge! With high confidence we can claim that this is by far the strongest chess event in history.

Putting the record into perspective and “human terms”: imagine a classical tournament at a time where Carlsen and Kasparov close to 3000 ELO and Caruana, Aronian, Firouzja, Topalov, Anand, So, Nakamura, Kramnik, and Giri are all above and around 2900 ELO. Now this is what we are viewing in computer chess at TCEC Swiss 7!

Here is a comparison of the top 10 participants in Swiss 1 and Swiss 7 events. The difference of rating jumps is even bigger among the rest of the participants.

Breaking the participation record

The state of computer chess – thriving! The sector has experienced a recent !boom with the development of new technology and ideas. For the first time ever TCEC had more applications than the event can accommodate. As a result, various engines had to undergo qualifications tournaments, raising the average ELO of the field even more.

TCEC Swiss 7 seeding and participants

This is the full participants list of TCEC Swiss 7 according to seeding. The seed number is determined according to the season rules, starting with the previous champion of TCEC – LcZero

1. LCZero (defending champion of TCEC Swiss 6)
2. Stockfish (Season 26 league champion)
3. Berserk
4. KomodoDragon
5. Ethereal
6. Seer
7. Ceres
8. RubiChess
9. Stoofvlees
10. Caissa
11. Obsidian
12. rofChade
13. Viridithas
14. Igel
15. Revenge
16. Arasan
17. Clover
18. Lizard
19. Velvet
20. PlentyChess
21. Minic
22. Uralochka
23. Stormphrax
24. Ginkgo
25. DeepSjeng
26. BlackMarlin
27. Marvin
28. Altair
29. Equisetum
30. Booot
31. Weiss
32. Tucano
33. Halogen
34. Renegade
35. akimbo
36. Texel
37. Winter
38. Devre
39. ChessFighter
40. Patricia
41. Princhess
42. ice4
43. 4ku
44. Heimdall

Which record is not broken?

TCEC Swiss 7 is part of the 27th edition of TCEC. It is one of the four titles that the engines can compete for, namely the Swiss, FRC, Leagues, and Cup titles. Inherently, every season is stronger than the previous one. Engine chess is booming, authors are more active than ever, technology is developing, ideas are growing. This season and the TCEC Swiss 7 event seems to break all records, but one. It is the TCEC Leagues S11 record, where the Premier Division average rating grew by 150+ ELO points. The average ELO of top 10 engines then was 3351 points, a full 150 points jump.

Another record in sight is the audience. The most viewed season of TCEC was 2 million people audience. Back then it was fueled by Carlsen’s World Chess Championships success. Since then TCEC seasons have crossed 1 million viewers several times, but has never been close to this record.

TCEC 4k IV standings

1. Ice4 43,5/48
2. 4ku 40,0
3. Stro4k 36,0
4. Molly 20,5
5. M4sseur 19,5
6. Moonfish 5,0
7. Pygone 3,5

Next: the 4k IV mini final, watch live at Visit the TCEC 4k live page / Follow TCEC on Twitch

From time to time TCEC treats us with side events. Currently ongoing is one of the most amazing such bonuses – the TCEC 4k competition. The key: all participating engines are limited to to a maximum of 4KiB (4096 bytes)

In modern age it is a challenge to find applications of this size. At TCEC, however, the competitors not only meet the requirement, but play above GM level. The top two engines – Ice4 and 4ku – even participate successfully in the regular season, boasting ELO of over 3000.

Visit the TCEC 4k live page / Follow the games on Twitch