What they lacked in “understanding” they more than made up for in tactical ingenuity, and already they were critical parts of top-level preparation. By that point Fritz, Hiarcs, Rybka, and Shredder were, from a practical perspective, the strongest chess playing entities on the planet. In 2008 I referred to Fritz, then the strongest engine around, as something akin to the spell-check function in your word processor, a utility to catch blunders during analysis. Anyone with even a modern cellphone effectively has a Super-GM analyst and coach at their beck and call, willing and able to answer questions 24 hours a day. But that immense, unfathomable strength is what makes them so important for human players to use and understand. It’s gotten to the point that the authors of Komodo are, in conjunction with, sponsoring handicap matches between Komodo and masters, even spotting FIDE Masters a full knight. Almost every mature, well-written engine is more than strong enough to defeat any human alive. Almost immediately some Twitter followers began to ask (I assume in good faith!) why they should be “excited” about a commercial neural net engine when Leela and Stockfish, both free to download and use, are “better.” It’s a good question, but to answer it, we have to do a bit of back tracking and ask another one: what’s the point of using a chess engine at all? Let’s begin by admitting the obvious.

I found that Fat Fritz was marginally weaker than the strongest Leela nets and development versions of Stockfish on my machine, something that appears to be borne out by further independent testing.

After describing the difference between traditional engines and neural nets, I then discussed the results of my early testing of Fat Fritz, and in particular, its performance in six engine-engine matches. For those who have not read Part I, here’s a brief recap: Fritz 17 includes the new Fat Fritz engine, a neural network with roots in the open-source Leela Chess Zero project. What is a chess engine’s raison d'être? I ask the question, only partially tongue in cheek, because of the early reaction to Part I of this review, which hit the web on Sunday.

Fritz 17 vs 16