TCEC FRC6, CCC20 Rapid Finals; Both Underway

The previous report on the world's top two engine vs. engine competitions was Stockfish Wins TCEC S24; Engine Mysteries (May 2023). To summarize that post:-

TCEC: Stockfish beat LCZero +20-16=64 to win the S24 Sufi. The site then conducted the following events: S24 VVLTC Bonus, S24 Kibitzer Bonus, and S24 4k 2, It is currently running the 'S24 4k 2 Final' • CCC: The site ran two 'CCC20 Rapid' events, a 12-engine 'Main' and a 6-engine 'Semifinal'. The 'Semifinal' was won by Stockfish, ahead of Lc0 and Dragon. Stockfish qualified for the 'Final', while the other two engines will play a 'Challenger Match' to determine the second finalist. Then followed an interlude of a series of 'Mystery' matches. Mystery beat Koivisto by a wide margin and is currently leading Berserk.

The report mentioned 'a couple of mysteries', which I still haven't resolved. Following is a roundup of the current situation.

TCEC: In the 'S24 4k 2 Final', ice4 beat 4ku +5-4=15. The site then launched a chess960 event, 'S24 FRC6'. For more about the event, see TCEC FRC 6 and TCEC FRC rules. The event is currently in the 'First phase - League C', the third of four preliminary six-engine double round robins.

CCC: Mystery played five 100-game matches, beating Koivisto, Berserk, and Ethereal; then losing to Dragon and Lc0. In the 250-game 'CCC20 Rapid Challenger Match' Lc0 beat Dragon 129.5-120.5, and is currently losing to Stockfish by seven points in the 'Finals' after a little more than a quarter of the 250 games have been played.

[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; Dragon = KomodoDragon]