Stockfish Wins TCEC Cup 7; CCC GPUs Back

In the previous post on the world's two foremost engine-vs-engine competitions, Stockfish Wins TCEC S19; CCC15 Still Halted (October 2020), I reported,

TCEC: Stockfish beat LCZero in the S19 final by a final score of +18-9=73. The match was technically decided after 93 games. • CCC: The title 'CCC15 Still Halted' said it all, although there was a short, unconfirmed rumor that the 'GPUs are back'.

In the meantime, the TCEC has conducted its premier side event, while the CCC shows signs of resuming normal operation.

TCEC: In TCEC Cup 7, Stockfish confirmed its S19 domination by beating LCZero in the final match. Stoofvlees beat Komodo in the consolation match for 3rd and 4th places. The last time I reported on a TCEC Cup, Alliestein Wins TCEC Cup 6; CCC Tests 'Stockfish NNUE' (August 2020), the main takeaway was 'In Cup 6, the AI/NN engines dominated.' How could we have known that NNUE would breathe new life into Stockfish ?

The site is currently running 'Sufi Bonus 3'. The '!next' plan says, 'next FRC2 testing and FRC2 ~1.5 weeks'. When was FRC1? As far as I can tell, it was more than six years ago. In Stockfish, the Strong (July 2014; Chessdom.com: 'Stockfish is TCEC double champion'), I started the post asking 'Which engine is the strongest at chess960?' Then I went on to feature the event in two posts on my chess960 blog:-

• 2014-08-02: TCEC Season 6 - Chess960 (chess960frc.blogspot.com)
• 2014-08-09: An Engine-to-Engine Opening (ditto)

I'm looking forward to reporting on FRC2 for the same blog.

CCC: The GPU problems are apparently over. The site is currently running an event called 'Checkmate in 4' with a GPU engine, Lc0. Why is it called 'Checkmate in 4'? We may never know. The associated 'Info' tab lists the four engines that are participating, says 'Testing and tuning new engine', and gives an associated PGN file. I downloaded the file and discovered that it was for an event called 'Mystery Engine Debut and Tuning', which was the name of the event preceding 'Checkmate in 4'.

What was the 'Mystery Engine'? We may never know, although some sources are certain it was 'Komodo NNUE'. Whatever the mystery engine was/is, it finished fourth out of seven engines, including Lc0 plus two other GPU engines.

Will CCC15 be resumed anytime soon or will it be abandoned? For the first report on the CCC15 GPU problems, see TCEC S19 DivP Chugging Along; CCC15 Halted (September 2020).

[For further information from the various stakeholders in the engine-to-engine events, see the tab 'TCEC/CCC Links' at the top of this page. • NB: Leela = LC0 = LCzero]