The Premier Division of TCEC Season 23 is over, and we will see Stockfish take on Leela in the superfinal while Komodo Dragon takes on Ethereal in the infrafinal. Although this was the foreshadowed result at the halfway mark, the second half of the division brought up plenty of drama. I had written then that it would take a major shock for Stockfish to miss the superfinal, which did not materialize, and Stockfish cruised through. On the other hand, Leela had a 1.5-point lead over Komodo Dragon, a lead that meant Komodo Dragon realistically needed to win an opening against Leela to stand a chance. And it happened! Komodo scored a crucial 1.5-0.5 win over Leela in the third round and, coupled with wins over the entire chasing pack, Komodo would have caught Leela there and then had Stockfish not won a third opening Komodo. With only a half-point gap now, a tense fourth round saw Leela draw Komodo in the head-to-head while dropping points against Ethereal. Meanwhile, Komodo kept winning, once again recording wins against the entire chasing pack to set up a nervy finale. With two rounds left, Leela needed to either beat Stockfish with White, or hope for Stockfish to notch yet another win against Komodo, in which case Leela would make the superfinal on the second tiebreak (Sonneborn–Berger score). Leela failed to shake the unshakeable Stockfish, and so had to pray for a fourth Stockfish victory. The opening was a difficult one for Black, but Stockfish had managed to defend it, so it was possible Komodo might manage the same. For a while it looked like Komodo might hold, but eventually Black’s bad light-square bishop proved a decisive liability. Stockfish broke through to send Leela to the superfinal. It was the first time since Season 14 when the superfinalists had been decided by tiebreak.
TCEC Season 23 so far: Full standings Premier Division / Ethereal trailblazes TCEC League 1 / Minic convincingly wins TCEC League 2
The fight for fourth place was less dramatic. Ethereal continued to play well, losing no openings to lower-ranked engines. It finished with 28/56, four points ahead of Stoofvlees. Stoofvlees went through a harrowing moment where it looked like SlowChess might catch it in fifth – SlowChess scored a head-to-head win in the third round while also drawing against Stockfish. Nonetheless, the 2.5-point lead at the halfway mark proved a bridge too far. SlowChess’s final score of 23/56 left it a point behind Stoofvlees, but three points ahead of rofChade in seventh. rofChade was the only engine to not win an opening in the division, but it did manage to score more draws than Berserk to finish half a point ahead.
The infrafinal is next, with Ethereal taking on Komodo Dragon in a 100-game match. Komodo Dragon is the heavy favorite, and the main question is whether Ethereal will win any openings. It is rare for the Big Three to lose to other engines, and losing an opening is even rarer. Still, with Ethereal having shown great progress in the Premier Division & 50 openings to play, it might well manage a couple. Testing is currently in progress and the infrafinal is slated to start in a day’s time. All games will be played live at the official website: https://tcec-chess.com/ and TCEC Twitch TV
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