The engines that will play in the season 27 entrance league are:
relegated from season 26 league 2: BlackMarlin, Marvin
played in season 26 entrance league: Altair Equisetum Booot Weiss Tucano akimbo Texel
new to TCEC (played in Swiss tournament): Ceres Devre PlentyChess Lizard Renegade Patricia
returning to TCEC: Halogen (season 25 league 2)
Final Standings
Ceres, Devre, BlackMarlin, PlentyChess and akimbo qualify to play in league 2. Ceres is supposed to be premier division material, it won 13/15 game pairs. Devre and BlackMarlin were ahead of the other engines from the start, Devre lost a single game pair to Ceres while BlackMarlin did not lose any. According to TCEC Elo BlackMarlin's result is somewhat surprising. PlentyChess was in 4th place with akimbo close behind, in the last rounds Halogen also joined the race. In the end PlentyChess kept its place, Halogen was 5th before the last round but lost its last game, akimbo won to take the 5th qualifying spot.
The 5 qualifiers will play in league 2 together with:
played in season 26 league 1 - Arasan, Velvet, Minic
played in season 26 league 2 - Uralochka, Stormphrax, Ginkgo, DeepSjeng
Interesting games
game 17, Weiss - Texel: On move 43 evals were low, Texel had connected passers in the center and Weiss had two passers on the king side. Weiss' eval jumped, Texel gave a rook for a knight and one white passer. After exchanging queens the second white passer became strong and Texel lost a rook and the game for it.
game 18, Devre - Booot: The engines shuffled with all pawns on the board, evals dropped to 0, Devre gave a rook for a knight to reset the 50 move counter. Booot blundered and the game reached a RN vs RR position with the black king and rook trapped on the queen side. Booot had no good moves and Devre captured 4 pawns to win.
game 22, Ceres - Patricia: Ceres was up a rook for a bishop and the game reached a RR vs RB position. After trading pawns Ceres trapped and captured the black bishop, then reduced to a tablebase win.
game 37, Ceres - Halogen: Ceres trapped the black king and reduced to a QR vs QN position two pawns down. After exchanging queens the white king was very active, Ceres captured pawns and created passers to win.
game 38, BlackMarlin - Altair: BlackMarlin slowly pushed the b pawn forward, then with both rooks on the 7th rank captured the b7 pawn and created a passer. Both engines managed to promote a passer but Altair lost material, the game reached a bishop vs pawns ending, BlackMarlin queened again to win.
game 48, Devre - akimbo: Devre had a strong bishop behind the black pawns, akimbo struggled to create space for its pieces. The black king was under threat after the g file opened, then Devre created a pawn majority on the queen side. akimbo lost a rook for a passer, Devre gained more material and mated.
game 50, Renegade - Devre: The engines shuffled for a long while, on move 114 Renegade gave a knight for a passer and Devre's eval jumped. The game reached a N vs BN position, Renegade had a passer on the 7th rank and it took Devre a while to capture it. After exchanging knights Devre pushed a passer to win.
game 53, BlackMarlin - Equisetum: BlackMarlin created a pawn majority on the queen side. The engines slowly exchanged pieces and the game reached a QR vs QR position. After exchanging queens all the pawns on the queen side were captured, BlackMarlin quickly captured two pawns on the king side to win.
game 67, Ceres - Devre: The game reached a double rook ending, Devre had a passer in the center and Ceres had a pawn majority on the king side. Ceres created a passer and the white king moved forward to support it. Devre lost a rook for the passer, game over.
game 71, PlentyChess - Halogen: The king side opened and PlentyChess attacked the black king. Halogen exchanged down to a RN vs RB position, PlentyChess placed a rook on the 7th rank and the white king moved forward. Halogen lost material and was mated.
game 79, akimbo - Ceres: Evals were negative, they remained mostly stable while the engines shuffled and exchanged pieces and pawns. In a QR vs QB position with black 3 pawns up akimbo exchanged queens on move 97 and evals jumped. Ceres pushed connected passers to win.
game 80, Renegade - Lizard: Renegade was up a pawn early, it captured a second pawn and created a passer on the queen side. The passer moved slowly forward, in a RN vs RN position Lizard captured the passer but lost its remaining pawns. Renegade pushed passers to win.
game 82, Ceres - Renegade: Evals slowly increased with only one pawn exchange until move 33. The position opened and the engines reduced to a RB vs RB position, white with a pawn up and a passer in the center. Ceres captured the bishop for the passer, then reduced to a tablebase win.
game 98, BlackMarlin - Lizard: The black king moved without castling, by the time it found safety on the queen side BlackMarlin had a passer on the king side. Lizard captured the passer and the game reached a double rook ending with white a pawn up. BlackMarlin had connected passers, it queened one to win.
game 99, Marvin - Renegade: Marvin captured a rook for a bishop though its king was exposed. The game reached a QR vs QB position, Renegade pushed a passer and was sure it could hold. However, Renegade had no tablebase access, Marvin captured the passer, exchanged queens and reduced to a tablebase win.
game 109, akimbo - PlentyChess: Evals increased steadily from the start, akimbo had more space, a bishop pair and control of the open b file. akimbo trapped a black rook but preferred to capture a pawn and create a passer. akimbo captured another pawn and reduced to a RB vs RN position, it used its passers to win.
game 116, PlentyChess - Renegade: PlentyChess was a pawn up with a passer on the queen side, the game reached a RRN vs RRB position and Renegade created a passer in the center. The engines exchanged a pair of rooks and PlentyChess pushed the passer to the 7th rank. PlentyChess gave a pawn and created a second passer, Renegade lost the rook for a passer, game over.
Standings after RR1: Ceres +9, Devre BlackMarlin +6, PlentyChess +3, akimbo +2, Renegade Lizard Halogen +1, Altair Equisetum 0, Patricia -2, Weiss -3, Booot -4, Tucano -5, Marvin -7, Texel -8. Ceres leads with no loss, two black wins against bias and only one draw in white against BlackMarlin. BlackMarlin and Devre are in joint second, BlackMarlin without loss while Devre lost one game against Ceres and won one game in black. The 4th qualifying place is still competitive with five engines within one point of each other.
game 126, PlentyChess - Lizard: PlentyChess gave a pawn and created an advanced passer on the queen side. Lizard created an advanced passer on the king side and the game reached a QRB vs QRB position with both passers blocked. The white passer was better protected, PlentyChess captured the black passer and exchanged queens. Lizard gave the bishop for the white passer, PlentyChess used its last pawn to force mate.
game 131, Ceres - PlentyChess: The engines opened the b file and Ceres controlled it with a rook. Evals increased slowly, Ceres gave a pawn and created a passer on the king side. Ceres regained the pawn and traded two minors for a rook. After exchanging queens the white passer slowly advanced and PlentyChess lost a knight for it. In a BBN vs R position Ceres captured pawns and trapped the black king to win.
game 133, Renegade - Altair: Renegade had a bishop pair and an early pawn advantage but its king was exposed. Altair regained the pawn and traded two rooks for the white queen, Renegade captured a knight and the game reached a RRB vs Q position. The engines traded pawns until there was only one white pawn left, the game ended in a tablebase win.
game 135, Devre - Equisetum: The game reached a RBB vs RR position with black two pawns up. After exchanging a pair of rooks Devre pushed a passer to the 7th rank and Equisetum traded a rook for a bishop to capture it. Devre's last pawn secured the win.
game 140, Halogen - Renegade: The game reached a BN vs BN position with white a pawn up. Halogen pushed a passer and Renegade gave the knight for it, the game ended in a tablebase win.
game 149, Lizard - Halogen: The engines exchanged pieces and pawns and opened the king side. The game reached a QRB vs QRN position, Lizard avoided a queen exchange for a long while. When it was ready Lizard exchanged queens and captured the knight, it used a passer to gain more material and won.
game 155, Booot - Renegade: The game reached a BN vs BN position with white a pawn up. Booot created a passer and exchanged bishops, then it captured another pawn and reduced to a tablebase win.
game 183, Lizard - Devre: The game started with a bias for black, the engines quickly reduced to a QRN vs QRN position with black a pawn up. The engines exchanged rooks and Devre captured another pawn. Devre slowly pushed passers forward, then forced a queen exchange to win.
game 186, akimbo - Lizard: The game reached a QRR vs QRN position with black a pawn up. It took akimbo a while to capture two pawns and then exchange queens. The engines continued to trade pawns and the game ended in a tablebase win.
game 195, PlentyChess - Equisetum: The engines castled in opposite directions, each engine pushed pawns facing its opponent's king. The long DS diagonal was open and a threat to the black king, Equisetum gave a rook for the white DS bishop and a pawn, also exposing the white king. In a RRB vs RBN position Equisetum lost the knight for a passer. PlentyChess had no pawns but its extra rook was enough to win.
game 199, Ceres - akimbo: There was a black bias from the start, the engines opened the position and exchanged pieces and pawns. The game reached a rook ending with equal pawns but akimbo had a passer on the 2nd rank. akimbo gave up the passer but captured two pawns and created another passer. The black king moved forward to support the passer, the game reached a 7-man position and akimbo managed to convert the win.
Standings with 5 rounds to go: Ceres +14, Devre +9, BlackMarlin +8, PlentyChess +5, akimbo +4, Halogen +2, Renegade +1, Lizard Equisetum 0, Altair -1, Booot -4, Patricia Tucano -5, Weiss -7, Texel -9, Marvin -12. Ceres increased its lead, Devre and BlackMarlin will almost certainly qualify though they may change places. PlentyChess is in fourth place but akimbo is close behind, this race is not over yet.
game 208, Halogen - Altair: Halogen was a pawn up and the engines shuffled in a closed position. Altair started to open the position but this turned out to be a bad idea. The engines traded Q for RB then reduced to a king and pawns endgame. Halogen was a pawn up and that was enough to win.
game 215, BlackMarlin - Renegade: BlackMarlin gave a bishop for pawns and exposed the black king. Renegade gave a piece back and the game reached a RB vs RB position with white a pawn up. BlackMarlin had a passer it kept safe until the engines exchanged rooks. The game ended in a tablebase win.
game 218, Lizard - BlackMarlin: The black king moved without castling, Lizard gave a knight to expose the black king. The white rooks controlled the center files and Lizard captured a rook for a bishop. The game reached a QR vs QBN position, Lizard pushed a passer foreward, then gave the rook and queened to win.
Standings with 2 rounds to go: Ceres +15, Devre +10, BlackMarlin +8, PlentyChess +6, akimbo +5, Halogen +4, Equisetum Renegade +1, Lizard 0, Altair -2, Booot -4, Weiss -6, Patricia Tucano -7, Texel -10, Marvin -14. BlackMarlin lost its first game of the league, it is a point behind Devre and probably will not be able to close the gap in the last two rounds. PlentyChess and akimbo are still fighting for 4th place, PlentyChess held as black against Devre. They still have to face each other with PlentyChess as white. Halogen is also close after two wins, it needs a miracle to reach 4th place.
game 229, PlentyChess - akimbo: After many early exchanges the game reached a RBN vs RBN position, the white rook was more active and PlentyChess created a passer in the center. Eventually akimbo lost material for the passer, PlentyChess won a knight vs pawns ending.
Devre and BlackMarkin drew their games, Halogen beat Booot and PlentyChess beat akimbo. One round to go Devre has a 1 point lead over BlackMarlin and PlentyChess has a 1 point lead over Halogen.
game 239, Weiss - Halogen: Weiss was a pawn up with a passer on the queen side. Weiss gave a bishop for pawns and exposed the black king. Halogen gave material and pushed a passer to the 2nd rank, but was not strong enough. Weiss trapped the black king and pushed its passer to win.
In the last round Devre and BlackMarlin won (BlackMarlin as black against Texel with a white bias), PlentyChess drew its game, akimbo won and Halogen lost. As a result akimbo is 5th ahead of Halogen in the final standings.