In a historic edition of the Premier division of TCEC, defending champion Stockfish qualified for the Superfinal half a point ahead of Komodo Dragon, who was in turn three points ahead of 3rd placed Leela Chess Zero.
Stockfish did not have it easy, and for much of the division it trailed Komodo Dragon after the latter benefited from a Scorpio blunder in the first double round robin (DRR) to record a 2-0 double kill. Still, Stockfish turned in a near-flawless performance – it won all but two white games it played against the bottom five engines while successfully drawing every game with black, and further scored a head-to-head win against Komodo Dragon. It finished the division as the only engine not to lose a game. Komodo Dragon was almost as dominant against the lower half of the field, but the loss to Stockfish, coupled with a difficult loss to Stoofvlees in the third DRR, left it half a point behind in second. Season 21 runner-up and fan favorite Leela Chess Zero finished third. It was the only engine not to lose to Stockfish, but it fell behind in the first DRR when it lost to rofChade in spite of winning the reverse, and its chances of reaching the Superfinal dimmed further when it failed to convert superior positions against Stoofvlees and Slowchess in the second DRR. It finally finished third, 3 points behind Komodo Dragon, but 8 points clear of rofChade in 4th place.
Speaking of rofChade, this engine returned with NNUE this season after playing without it in the previous two seasons. The effect was immediate, as after getting relegated to League 2 in Season 21, rofChade not only navigated its way to Premier Division but also pipped perennial dark horse Stoofvlees into fourth place. Stoofvlees had a bad start in the division, losing openings to Slowchess and Igel, before eventually clawing its way back to finish fifth. Playing in the Premier Division for the first time, newcomer Slowchess flirted with relegation, but capitalized on ScorpioNN’s misadventures to survive the drop. ScorpioNN had been involved in relegation battles for the past several seasons, and its streak finally ended this season when it lost twice with White – in addition to the blunder against Komodo, ScorpioNN crashed once against Igel. Igel, the only engine playing without an update, still managed to win an opening against Stoofvlees, but was unable to capitalize on the unexpected gift from ScorpioNN’s crash to finish last.
Next up is the infrafinal, between the 3rd and 4th place finishers – so Lc0 and rofChade. Leela is starting as the heavy favorite, with most viewers predicting a Leela victory by roughly 10 points – a very substantial margin of victory given the shorter length of the infrafinal.
After the infrafinal, Stockfish and Komodo Dragon will take the stage. It will be the first Superfinal since Season 13 in which no GPU-based neural-network engine has competed in, and the first Superfinal between two NNUE engines. It will also be the first time Komodo – still the second-most successful engine in TCEC – has reached the Superfinal since Season 13. Stockfish developer Michael Chaly has already predicted a crushing victory for Stockfish.
Special thanks to Cato the Younger
This Premier Division was the last one to have a book by Nelson Hernandez aka Cato the Younger. His contributions to TCEC openings during many seasons and events have been invaluable. Thank you, Cato!