Ethereal and Berserk are the promoting engines from League One of the premier computer chess event – the Top Chess Engine Championship. Ethereal crushed its way through the division with a 30/44 score, 3.5 points ahead of Berserk, who in turn finished 1.5 points ahead of League Two winner Minic. Unfortunately for the other engines that promoted from League Two, all three are relegating, along with last season’s Premier Division engine Igel.

Starting soon: Follow the Premier Division of TCEC live – with Stockfish, Lc0, Komodo, Stoofvlees, RofChade, SlowChess, Ethereal, and Berserk

Although expectations were for a close League One, things sorted themselves out fairly quickly. Berserk and Ethereal both took the lead with 2.5/3 in their first three games, before Ethereal scored a head-to-head win against Berserk in round 5 to take over. It never looked back – by the end of the league, it had won both openings against both Berserk and Minic, not to mention Seer and Scorpio. In fact, Ethereal is the only engine not to lose an opening in the division, with a positive score against all its rivals except Arasan. This excellent performance shows Ethereal’s 3rd-place finish in last season’s FRC leagues was no fluke, and in fact going into Premier Division, viewers favor it to qualify for the infrafinal (the 3rd-place match between the engines finishing 3rd-4th in the division). Unfortunately, Ethereal developer Andrew Grant remains unsatisfied. Asked if he was happy after Ethereal’s win over Igel in the first round, he said that he would not be happy unless Ethereal won the reverse. Although there were three double kills in the League One, Ethereal did not score any. Poor Andrew Grant – if there can be no double kills then he will be unhappy forever

For the other competitors, ScorpioNN dramatically lost on time in the first round against Minic while in a completely winning position. This stroke of good fortune gave Minic an extra 1 point that ultimately let it place above RubiChess & Revenge. For ScorpioNN, the silver lining was that the bug is apparently rare – ScorpioNN developer Daniel Shawul said ScorpioNN had built-in failsafes that failed to trigger, and he was not able to identify the root cause. ScorpioNN did not lose any more games on time and ultimately stayed in the division. Pre-tournament Koivisto was probably the biggest disappointment of all. It did so poorly that at one point it was in danger of being relegated. Koivisto’s developers eventually figured out that a SMP bug had caused Koivisto to lose over 80 elo when playing under TCEC conditions, more than enough to relegate it from one of the frontrunners of the league to the tail-end. Very unfortunate for Koivisto, but the League Two engines are all probably heaving a sigh of relief. Finally, Igel was relegated for the second season in a row. League One is very competitive.

Next up is Premier Division, where last season’s record-setting winner Stockfish will be looking for a repeat, while its rivals attempt to stop a repeat. The “Big Three” (Stockfish, Leela and Komodo Dragon) are once again favorites for the top three positions, but the rest of the places look to be very contested. Ethereal is currently the favorite to finish fourth and qualify for the infrafinal, but it will have to beat out perennial dark horse Stoofvlees and last season’s 4th-place finisher rofChade. Although rofChade, Stoofvlees and SlowChess are technically playing without an update, that is only in comparison to last season’s FRC leagues two months ago. The three engines are updated relative to last season’s Premier Division. Still, with Igel showing how fast League One engines are improving, there is a real chance Ethereal and Berserk will do well. All games will be played live at https://tcec-chess.com/

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