A few days ago, ChessBase released Fat Fritz 2, described on their website as the "new number 1" chess engine "with a massive new neural network, trained by Albert Silver with the original Fat Fritz."
They advertise Fat Fritz 2 as using novel strong ideas compared to existing chess engines, but in reality Fat Fritz 2 is just Stockfish with a different neural network and minimal changes that are neither innovative nor appear to make the engine stronger.
As this is not the first time something like this has happened involving both ChessBase and A. Silver, we would like to share our impression of these releases.
See full Lichess blog:
Open Source Community Critical Of Chessbase, Fat Fritz 2
The development teams behind the two most successful and influential open-source chess programs, Stockfish and Leela Chess Zero, have issued statements denouncing the commercial program Fat Fritz 2 and the company Chessbase that is selling the program for 99,90 euros.
The statements (Stockfish blog, lichess announcement) assert that the engine in Fat Fritz 2 is Stockfish with minimal changes, that Fat Fritz 2 has violated the GNU General Public License under which Stockfish is released, and that Chessbase's marketing has made false claims about Fat Fritz 2's playing strength.
See full Chess.com article
Official test by SF team, at fishtest conditions, of Stockfish 13 vs the sold version of CB/AS (ff2) net and the corresponding Stockfish player.
TC 10+0.1: PGN
../ordo -a 0 -p out-sf13-vs-ff2-TC10+0.1.pgn -A sf13 -s 100 -q -J -D -W # PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%) 1 sf13 : 0.0 ---- 34445.5 65536 53 100 2 ff2 : -18.1 1.3 31090.5 65536 47 --- White advantage = 29.29 +/- 0.67 Draw rate (equal opponents) = 77.35 % +/- 0.18
TC 60+0.6: PGN
../ordo -a 0 -p out-sf13-vs-ff2-TC60+0.6.pgn -A sf13 -s 100 -q -J -D -W # PLAYER : RATING ERROR POINTS PLAYED (%) CFS(%) 1 sf13 : 0.0 ---- 33774.0 65536 52 100 2 ff2 : -10.8 1.0 31762.0 65536 48 --- White advantage = 24.72 +/- 0.50 Draw rate (equal opponents) = 87.77 % +/- 0.14
Setup and parameters
Same setup as fishtest, using 8moves_v3.pgn book, run in 128 batches
(command used for TC 60+0.6):
../cutechess-cli \ -repeat -rounds 1 -games 512 -tournament round-robin \ -srand $RANDOM -resign movecount=3 score=400 \ -draw movenumber=34 movecount=8 score=20 -concurrency 64 \ -openings file=../8moves_v3.pgn format=pgn order=random plies=16 \ -each tc=60+0.6 option.hash=64 proto=uci -ratinginterval 128 \ -engine cmd=../stockfish.sf13 name=sf13 \ -engine cmd=../stockfish.ff2 name=ff2 \ -pgnout out-sf13-vs-ff2.pgn
Compiled using exactly the same compiler and same settings
on master at SF13 commit
make clean && make -j ARCH=x86-64-avx2 profile-build mv ./stockfish ./stockfish.sf13 ./stockfish.sf13 bench 2>&1 | grep "Nodes searched" Nodes searched : 3766422
on ff2 branch with the correct CB/AS net added to the src directory
make clean && make -j ARCH=x86-64-avx2 profile-build mv ./stockfish ./stockfish.ff2 ./stockfish.ff2 bench 2>&1 | grep "Nodes searched" Nodes searched : 4025201
ChessBase’s Fat Fritz 2 condemned as ‘rip-off’ Stockfish clone
Stockfish and Leela Chess Zero developers have joined together with Lichess to condemn what they see as false advertising by ChessBase of the recently released Fat Fritz 2 chess software. The promotional material suggests the chess engine included with the software is “the new number 1”, and that the key contribution is Albert Silver’s in training its neural network. The Stockfish developers, meanwhile, point out that Fat Fritz 2, which is being sold for around 100 euros, is the free Stockfish with a net that adds no noticeable increase in playing strength.
See full Chess24 blog
Fat Fritz II and Stockfish- A Computer Chess Controversy
Anyone who's been paying any attention to chess Twitter or Twitch in the past few days will have heard of Fat Fritz II, the new chess engine from ChessBase and Albert Silver. They also will know that it's ignited a controversy that's spread well beyond the insular computer chess community.
Seriously, how often do GM Hikaru Nakamura and GM Anish Giri mention the Stockfish developers on Twitter?
What is Fat Fritz II? What does Stockfish have to do with this? And why is everyone so angry? That's what I'm here to explain!
See full the_real_greco's blog
I'm so disappointed in @ChessBase for selling FF2. It might be legal, but it's morally questionable and shockingly unoriginal.— Tord Romstad (@tordr) February 10, 2021
If your idea of innovation in chess is charging 100 EUR for changing the parameters of an open source engine, you're going to have some problems competing with https://t.co/omt8vnPgDW and https://t.co/YYvW1XZRCj.— Gian-Carlo Pascutto (@gcpascutto) February 9, 2021
“Once is happenstance, twice is coincidence, three times is enemy action.” LCZero, Stockfish and Lichess teams just posted a joint note explaining our stance on the recent Fat Fritz 2 release by ChessBase. https://t.co/I65CeQfNPs— Leela Chess Zero (@LeelaChessZero) February 18, 2021
ChessBase and Albert Silver claim that Stockfish is used in "commercial apps like Play Magnus". I wrote the AI part of that app. It's 100% my own work, based on an early ancestor of Stockfish for which I was the only author and had the full copyright. Not like FF2 at all.— Tord Romstad (@tordr) February 22, 2021