Fat Fritz

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Fat Fritz, a commercial chess entity by ChessBase, the first version released in November 2019 featuring a set of custom made neural network weights that work in the open source project Leela Chess Zero within its Lc0 executable, while Fat Fritz 2.0 released in February 2021 is based on Stockfish 12 and custom NNUE technology.

=Fat Fritz 1= Initially introduced as a cloud project in summer 2019, inspired by DeepMind's ground breaking AlphaZero approach combining Deep learning with Monte-Carlo Tree Search (MCTS) , and Albert Silver's Deus X experience, relaxing Leela Chess' "Zero" paradigm of pure reinforcement learning due to supervised learning, Fat Fritz was released in November 2019 as part the Fritz 17 package, best supported by a GPU card such as Nvidia GeForce 20 series. The project and its underlying techniques were emphasized by a talk of AlphaZero co-author Thore Graepel at ChessBase, attended by German computer chess icon Thomas Nitsche along with his sons and Math42 authors Raphael Nitsche and Maxim Nitsche. Fat Fritz was further supported by Daniel Uranga.

Lc0 and DeusX aka Fat Fritz components

=Fat Fritz 2= Fat Fritz 2, released on February 09, 2021, is based on NNUE technology and Stockfish 12 with a double sized network, and thus, running on a CPU, not requiring expensive GPU graphic cards for game playing like its predecessor. The network was trained by Albert Silver with the help of Daniel Uranga and Dietrich Kappe, who provided scripts and ideas. Further credits were given to the Stockfish contributors, and in particular Yu Nasu for his groundbreaking work on NNUE, and Hisayori Noda for the initial Stockfish NNUE implementation. Using the original Fat Fritz as initial supervisor to evaluate chess positions, the learning of Fat Fritz 2 was reinforced by Stockfish's alpha-beta search. The initial release had the 40 MiB NNUE file embedded inside the Fat Fritz 2 executable, and was soon separated after the intervention of the Stockfish community due to a possible GPL license violation. While the separated none GPL licensed NNUE file had a replacement on GitHub, it was not identical with the commercial purchased network, yielding in weaker play. The Stockfish community, denying Fat Fritz 2's originality as claimed by ChessBase, initially reacted with the release of Stockfish 13 on February 19, 2021. In summer 2021, the Stockfish team filed a lawsuit against ChessBase to enforce the consequences of the license termination concerning Fat Fritz 2 and the allegedly Stockfish derivative Houdini 6 sold by ChessBase.

=See also=
 * AlphaZero
 * Deus X
 * Fat Titz
 * Fritz
 * Leela Chess Zero
 * Stockfish NNUE
 * NNUE
 * YaneuraOu

=Forum Posts=

2019

 * 'Deus X' Unveiled as FAT FRITZ PROJECT... by supersharp77, CCC, August 13, 2019
 * Match between SF 10 and Fat Fritz by Steppenwolf, CCC, August 26, 2019
 * Chessbase's Albert Silver on LC0 & Fat Fritz by supersharp77, CCC, August 26, 2019
 * "Fat fritz" stronger than Stockfish ? by Mehdi Amini, CCC, September 24, 2019
 * UCI Win/Draw/Loss reporting by Gian-Carlo Pascutto, CCC, October 22, 2019
 * Fritz 17 by sainzlei, CCC, October 25, 2019
 * Nice review fo Fat Fritz by Jouni Uski, CCC, November 22, 2019 » Review

2020

 * Fat Fritz update by Nordlandia, CCC, March 05, 2020
 * Fat Fritz Update by Nordlandia, CCC, December 09, 2020
 * Re: Fat Fritz Update by Albert Silver, CCC, December 12, 2020


 * Fat Fritz for Linux by Joshua Shriver, CCC, December 20, 2020

2021

 * Fat Fritz 2 by Jouni Uski, CCC, February 09, 2021
 * Re: Fat Fritz 2 by gladius, CCC, February 14, 2021 » CCRL


 * If your idea of innovation ... by Gian-Carlo Pascutto, Twitter, February 09, 2021
 * Fat Fratz 2.0 Copyleft Infringement by Bernt Nicht, FishCooking, February 10, 2021
 * Re: Fat Fratz 2.0 Copyleft Infringement by Joost VandeVondele, FishCooking, February 10, 2021


 * I'm so disappointed ... by Tord Romstad, Twitter, February 10, 2021
 * Calling All Armchair GPL Lawyers by Andrew Grant, CCC, February 12, 2021
 * FF2 verses SF, what are the important differences? by Dann Corbit, CCC, February 13, 2021
 * Interesting read about Fat Fritz 2 by Marc-O Moisan-Plante, CCC, February 19, 2021
 * Are neural nets (the weights file) copyrightable? by Adam Treat, CCC, February 21, 2021
 * Fat Fritz 2 nets: Github posted vs commercial by Tibono, CCC, February 22, 2021
 * Why I stood up for Allie is why I stand up for FF2 by Dietrich Kappe, CCC, February 23, 2021 » Allie
 * The distinction between engines and neural nets by Madeleine Birchfield, CCC, February 26, 2021
 * An actual interesting computer chess read about FF2 by Dietrich Kappe, CCC, February 27, 2021 » Stephen Ham article
 * How to make a double-sized net as good as SF NNUE in a few easy steps by Chris Whittington, CCC, February 28, 2021
 * It walks like a clone, it quacks like a clone ... by MikeB, CCC, March 09, 2021
 * Time to rethink what Albert Silver has done? by Srdja Matovic, CCC, July 03, 2021
 * Fat Fritz question by Leo Anger, CCC, July 18, 2021
 * Stockfish: Our lawsuit against ChessBase by Kurt Lanc, CCC, July 20, 2021
 * Stockfish sues Chessbase! by mwyoung, ProDeo Forum, July 20, 2021

2022

 * SF vs ChessBase declared a draw by Dietrich Kappe, CCC, November 19, 2022

=Blog Posts=
 * Fat Fritz 2 - Ein unmoralisches Angebot by Topschach Benny, February 12, 2021 (German)
 * Statement on Fat Fritz 2 by Joost VandeVondele, Stockfish Blog, February 15, 2021
 * Fat Fritz 2 is a rip-off, The Stockfish, Leela Chess Zero and Lichess teams, February 16, 2021
 * ChessBase’s Fat Fritz 2 condemned as ‘rip-off’ Stockfish clone by Colin McGourty, Chess24, February 22, 2021
 * Open Source Community Critical Of Chessbase, Fat Fritz 2 by Peter Doggers, Chess.com, February 24, 2021 » Matthew L. Ginsberg
 * Our lawsuit against ChessBase, The Stockfish Team, Stockfish Blog, July 20, 2021 » Houdini 6
 * Fat Fritz is not the Only Ripoff and now ChessBase is Getting Sued, Lichess, July 20, 2021
 * Stockfish Developers Sue Chessbase Claiming Copyright Violation by Peter Doggers, Chess.com, July 23, 2021

=External Links=

Purchase

 * Fritz 17 - The giant PC chess program, now with Fat Fritz - ChessBase Shop
 * Fat Fritz 2 SE - ChessBase Shop
 * Fat Fritz 2 SE + Fritz Powerbook 2021 - ChessBase Shop
 * Fat Fritz 2.0 SE on Steam
 * Fat Fritz 2.0 SE, New In Chess
 * Fat Fritz 2.0 SE, House Of Staunton
 * Fat Fritz 2.0 SE, The Official Chess Shop of the US Chess Federation - Chess Pieces, Chess Sets, Chess Boards, Chess Clocks and More!
 * Amazon.com: Fat Fritz 2.0 Chess Playing Software Bundled with Chess Success II Chess Training DVD: Toys & Games

2019

 * Fat Fritz – What on Earth is that? by Albert Silver, ChessBase News, August 13, 2019
 * Using Fat Fritz in the Engine Cloud by Nadja Wittmann, ChessBase News, August 15, 2019
 * Analysing your openings repertoire with Fat Fritz, ChessBase News, September 02, 2019
 * GM preparation with Fat Fritz by Frederic Friedel, ChessBase News, September 12, 2019
 * Standing on the shoulders of giants by Albert Silver, ChessBase News, September 18, 2019
 * Fat Fritz analysis: A matter of technique by Albert Silver, ChessBase News, September 24, 2019
 * Fat Fritz: Small differences, big effect by Albert Silver, ChessBase News, October 09, 2019
 * "Fat Fritz seemed to be from an entirely different plane of existence!" by Tanmay Srinath, ChessBase News, November 04, 2019
 * Fat Fritz defeats Stockfish in 100-game matches by Elshan Moradiabadi, ChessBase News, November 06, 2019 » Stockfish
 * Fat Fritz outmatches Stockfish (part 2) by Elshan Moradiabadi, ChessBase News, November 07, 2019
 * Fat Fritz: what videocard to buy by Albert Silver, ChessBase News, November 14, 2019
 * Optimizing Fat Fritz, the top rated engine in the world by Albert Silver, ChessBase News, November 25, 2019
 * Fat Fritz in the cloud by Albert Silver, ChessBase News, November 28, 2019

2020

 * Fat Fritz for the club player by Tanmay Srinath, ChessBase News, January 09, 2020
 * Fat Fritz 1.1 update and a small gift by Albert Silver. ChessBase News, March 05, 2020
 * Out-preparing the Candidates with Fat Fritz (Part 1) by Tanmay Srinath, ChessBase News, March 21, 2020
 * Out-preparing the Candidates with Fat Fritz (Part 2) by Tanmay Srinath, ChessBase News, March 25, 2020
 * Fat Fritz: strong, creative, original by Stephan Oliver Platz, ChessBase News, March 27, 2020
 * Running Leela and Fat Fritz on your notebook by Evelyn Zhu, ChessBase News, June 14, 2020 » Leela Chess Zero

2021

 * Fat Fritz 2.0 - The new number 1, ChessBase News, February 09, 2021
 * Fat Fritz 2: The Best of Both Worlds by Albert Silver, ChessBase News, February 11, 2021
 * Interview with Albert Silver - His journey to Fat Fritz 2.0 by Arne Kaehler, ChessBase News, February 12, 2021, YouTube Video


 * How a neural network is made by Albert Silver, ChessBase News, February 21, 2021
 * Discussing moves with a neural network by Stephen Ham, ChessBase News, February 27, 2021
 * Steamrolling the king, ChessBase News, June 15, 2021
 * Solving the impossible by Albert Silver, ChessBase News, June 24, 2021

Fritz 17

 * Introducing Fritz 17 with Fat Fritz and other goodies, ChessBase News, November 12, 2019
 * Fat Fritz and Fritz 17: A Review (Part I) by John Hartmann, US Chess, November 17, 2019
 * Fat Fritz and Fritz 17: A Review (Part II) by John Hartmann, US Chess, November 19, 2019

Source Code

 * GitHub - DanielUranga/lc0 at uci-wdl-reporting by Daniel Uranga
 * lc0 84 - AppVeyor
 * GitHub - kiudee/bayes-skopt: A fully Bayesian implementation of sequential model-based optimization by Karlson Pfannschmidt
 * GitHub - yaneurao/YaneuraOu: YaneuraOu is the World's Strongest Shogi engine(AI player), WCSC29 1st winner, educational and USI compliant engine » YaneuraOu
 * GitHub - DanielUranga/Stockfish at ff2 by Daniel Uranga
 * ff2 · DanielUranga/Stockfish@e44edde · GitHub
 * FF2 · DanielUranga/Stockfish@faef72a · GitHub
 * Stockfish/FatFritz2_v1.bin at ff2 · DanielUranga/Stockfish · GitHub

Rating Lists

 * Fat Fritz in CCRL Blitz
 * Fat Fritz in CCRL 40/15

=References= Up one Level