I'm going through the games archive and looking at the results.
Entrance league
relegated from season 28 league 2: Velvet Igel Arasan Horsie
played in season 28 entrance league: BlackMarlin DeepSjeng Clover Patricia Renegade
new to TCEC (played in Swiss tournament): Torch Pawnocchio Quanticade Tarnished Heimdall
returning to TCEC: Winter (season 26 entrance league) Halogen (season 27 entrance league)
Final standings
Torch won easily with 15 game pair wins. Tarnished finished in second place, not expected considering its low ELO, but this is may be because it is new to TCEC and there are not enough games for an accurate ELO calculation. Tarnished lost to Torch and Horsie, had 11 game pair wins and 2 draws. Five engines were in the race for the remaining 4 qualification spots. Halogen and Quanticade finished in joint 3rd place, though Halogen won the direct minimatch. For Halogen this was a small improvement compared to its last TCEC appearance in season 27. Pawnocchio, Horsie and Clover were tied in 5th place and continued to a 3-way tiebreak. Pawnocchio was a clear winner in the tiebreak, but Horsie and Clover were again tied and played a second tiebreak, which Clover won. Of the five new engines only Heimdall failed to advance to League 2.
Pawnocchio crashed twice in the league, in both games the position seemed to be drawn. Hopefully this will get fixed in the next stages.
Arasan and Igel, both appearing many times in TCEC, failed to qualify - perhaps approaching retirement.
League 2
The 6 qualifiers joined
relegated from season 28 league 1: Seer rofChade Stoofvlees
played in season 28 league 2: Booot Ginkgo Uralochka
Final standings
Torch won the league easily, with 15/22 game pair wins and no losses. Pawnocchio and Halogen finished in second and third places, with 2 game pair losses each. The 4th qualifier was Clover with 4 game pair lossses, ahead of Quanticade and Ginkgo that had 4 or fewer losses but less wins than Clover. All 4 qualifiers started in the entrance league, two of them newcomers to TCEC.
At the bottom of the league were rofChade, Seer and Stoofvlees. These engines were members of the premier division in the past, but are on their way down and will have to play in the entrance league next season.
Pawnocchio was updated and had no crashes in the league. Tarnished performed worse when compared to the other qualifiers from the entrance league. It too was updated, perhaps this update was not an improvement.
League 1
The 4 qualifiers joined
relegated from season 28 premier division: KomodoDragon Ethereal
played in season 28 league 1: Reckless Caissa Stormphrax Ceres Viridithas RubiChess
Final standings
Reckless won the league with 13/22 game pair wins and no losses. Torch was second with 9 game pair wins and no losses. Both engines advance to the Premier division. This is the second TCEC season for Reckless, last season it finished 3rd in league 1, this season it improved enough to advance. Torch is new to TCEC, it managed to reach the premier division in its first TCEC season like Integral last season (and Stoofvlees many seasons ago).
Ceres finished in 3rd place, its first appearance in TCEC was in season 27 and it reached exactly the same place then, it still hasn't been able to advance further. Pawnocchio ended its first TCEC season in 4th place, after starting in the entrance league. Halogen also had a successful run this season after missing season 28, this is its best TCEC result.
KomodoDragon and RubiChess are still strong enough for league 1, both appeared in the premier division. KomodoDragon was a top engine for a long time, but apparently it is not developed further. Ethereal was also a long time premier division engine, its developer is focused on Torch and Ethereal seems to be dropping quickly.
