The Condemnation of Fat Fritz

Two weeks ago, in an off-week engine post, The Transformation of Fat Fritz (February 2021), I noted,

For the past few years, whenever there was a controversy in the world of chess engines, Fat Fritz was somewhere nearby.

What was the controversy?

• 2021-02-18: Fat Fritz 2 is a rip-off (lichess.org); 'An important message from open source chess organizations.'

Signed, 'The Stockfish, Leela Chess Zero and Lichess teams', the message started,

A few days ago, ChessBase released Fat Fritz 2, described on their website as the "new number one" 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.

The accusation was soon echoed by two of the most important chess news sites:-

• 2021-02-22: ChessBase?s Fat Fritz 2 condemned as "rip-off" Stockfish clone (chess24.com; Colin McGourty; comments) • '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.'
  
  
• 2021-02-25: Open Source Community Critical Of Chessbase, Fat Fritz 2 (chess.com; PeterDoggers) • '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.'

What did the engine experts have to say about the development? The storm of feedback started the day that ChessBase made its initial announcement.

• 2021-02-09: Fat Fritz 2 (talkchess.com)

That discussion alone totals 50 pages with 10 posts per page. Add another two dozen threads on the same subject on the Talkchess forum. This controversy could go on for months, maybe years. ChessBase GmbH certainly knows how to generate free publicity for itself.