Top Chess Engine Championship Swiss 8 is now live – with record hardware boost and the highest average ELO in history. It is immediately followed by the TCEC Cup and the TCEC Leagues Season 28.

TCEC Swiss 8 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.

Live video

Top Chess Engine Championship (TCEC), the world’s premier championship for computer chess, started its new season with the highly anticipated TCEC Swiss 8 tournament, featuring 44 of the world’s most advanced chess engines. This event surpassed 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 (record: see the press release), 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

Stockfish is sole leader after 16 games

After 8 double rounds, or 16 games, Stockfish is the sole leader of TCEC Swiss 8. In R8 Stockfish scored 1,5-0,5 vs Ethreal, while the surprise of the season Integral managed to hold Leela to a 1-1 draw. This was enough for Stockfish to collect 11,0/16, half a point ahead of Leela and 1,5 points ahead of Berserk, KomodoDragon, Integral, and PlentyChess.

Next round will see Stockfish – PlentyChess and Leela Chess Zero – Seer

Top Chess Engine Championship (TCEC), the world’s premier championship for computer chess, started its new season with the highly anticipated TCEC Swiss 8 tournament, featuring 44 of the world’s most advanced chess engines. This event surpassed 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 (record: see the press release), 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

After 7 double rounds of TCEC Swiss 8, Stockfish and Leela share the lead with 9,5/14 each. Leela won its match against Boot (replay here), while Stockfish defeated the surprising early leader KomodoDragon, overtaking it in the standings

TCEC Swiss 8 standings after 14 games

Top Chess Engine Championship (TCEC), the world’s premier championship for computer chess, launched 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

After 4 double rounds (8 games) there is a surprising leader at TCEC Swiss 8. KomodoDragon leads with 5,5/8, ahead of Lc0, Stockfish, Obsidian, Horsie, Berserk, PlentyChess, Caissa, Stoofvless, Ceres, and Ethereal, all with 5,0/8.

Standings after 4 double rounds

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

Follow Swiss 8 live: Official website / TCEC Chess TV / Innovations in TCEC / Live on Chessdom

Top Chess Engine Championship Swiss 8 participants

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.

TCEC started with a bang – the newcomer Caissa has taken the sole lead in the event after round 2! Caissa won a Sicilian game against KomodoDragon and a King’s Indian against Seer to score 2,0/2 and jump into sole first. Caissa is closely followed by Stockfish with 1,5/2. The defending champion drew its game vs KomodoDragon and defeated Obisidian. The third position is shared by Ethereal, Berserk, and Lc0 with 1,0/2.

More about Caissa chess engine

Caissa is a strong chess engine written from scratch in C++ by Michał Witanowski (Witek902). It employs a custom efficiently-updated neural network trained with self-play games using a custom trainer. It supports (D)FRC and endgame tablebases. In development since early 2021. TCEC debut S25 Swiss5 & EL. Best score for the engine is 9th position (S26 L1) and this year it has a guaranteed 8th or more, improving on the standings. Official website: Github.com/Witek902/Caissa

It’s a lovely opsitional squeeze from Leela starting from an opening position that suits its style down to the ground. An early (book) advance of the g-pawn in a Budapest Gambit secures Leela the f4-square for its pieces in perpetuity. Leela uses this asset beautifully to extract more and more concessions from Ethereal culminating in a tale of 2 rook’s pawns in a 2 bishops against 2 knights endgame: Leela’s rook’s pawn on h6 is invulnerable and crippling, Ethereal’s a4-pawn is weak and open to attack! The game is viewable here: https://tcec-chess.com/#div=sw&game=396&season=27

More: Leela Chess Zero wins TCEC Swiss 7 / Leela-Obsidian TCEC Swiss 7 (video) / Slicing and dicing the Budapest: Alekhine’s 4.e4… with a twist!