Season 21 league 2

Final standings

Pedone and Nemorino advance to league 1. The race at the top of the table was close in the first RR, the first 8 engines were within 1 point of each other. Pedone took the lead with a remarkable +7 score in the 2nd RR, including wins against some of its close competitors. The second qualifying spot was only decided in the last rounds, Nemorino was the only engine that managed to win a game and get ahead of the rest.

Winter, ClassicAra, Seer and Arasan are relegated to league 3. The bottom 3 engines accumulated losses from the start and it was clear they were going to be relegated. Halogen, Vajolet and Winter fought for survival and were close until the end. Winter was tied with Pedone after the first RR, but it dropped down after a poor -4 score in the second RR. In the end Winter's losses to both Halogen and Vajolet sealed its fate.  

The openings for league 2 were by Eduardo Sauceda. They were quite biased with one side starting with a pawn or even a minor piece advantage, including 18 versions of the King's Gambit. Despite this only 6/66 openings resulted in two wins, one for each engine. 

Booot and ClassicAra did not advance further, both started this season in the qualification league. Of the 4 engines that advanced from league 3 only Classic Ara is relegated back. Booot, Minic and Halogen get to stay in league 2.

Pedone and Nemorino will play in league 1 together with:
relegated from premier league in season 20 - Ethereal, rofChade
played in league 1 in season 20: Igel, Slowchess, RubiChess, Xiphos

Interesting games

game 4, Vajolet - Nemorino: Nemorino was a pawn up with a doubled passer, it may have missed a win when it captured another pawn and let Vajolet reduce to a BN vs BN position. Vajolet blocked the passers with its knight and Nemorino could only shuffle. Eventually Nemorino reduced to a drawn opposite color bishop ending.

game 5, Minic - Seer: Seer had an advantage from the opening but Minic managed to equalize. The white king walked to safety on the queen side, then Minic went a pawn up and created passers on the queen side. The game reached a QB vs QN position, Seer promoted a passer first and Minic gave its bishop to eliminate it. Minic was 3 pawns up, it slowly pushed its passers forward. Seer perhaps could have played better but after 30 moves it lost its knight for two pawns, and the queen ending was a win for white.

game 7, Booot - ClassicAra: ClassicAra chose a Q vs RB imbalance, Booot chased the black king all the way to the 1st rank. ClassicAra failed to build a fortress with its pieces, it started losing material and was mated in the end.

game 11, Arasan - Pedone: Arasan was up a rook for a bishop from the start, but its king was vulnerable in the center. Pedone attacked the king and managed to place a rook on the 2nd rank with an advanced central passer. Arasan reduced to a RR vs QB position but couldn't escape the mating net. 

game 14, Pedone - Halogen: Pedone sacrificed a knight early, its compensation was a significant development advantage, the queen was the only active black piece. However Pedone was too passive, Halogen managed to open the position and exchange pieces. Pedone pushed a passer to the 7th rank but there it was stopped, Halogen's extra piece became decisive. Halogen pushed pawns forward, it started to gain more material and won.

game 16, Minic - Fritz: The game reached a double rook ending, Fritz had passers on the queen side and Minic had a passer on the king side. Fritz chose to move its king to the queen side and this turned out to be a mistake. The white rooks captured two black passers, while Minic traded its king side passer for a rook and won. 

game 17, Defenchess - Nemorino: Nemorino had an advantage in a BN vs BB position, somehow Defenchess found a way to block a pair of black passers while keeping the black king away, while a white passer had to be watched by the bishops. Nemorino could only shuffle, eventually Defenchess gave its knight to take out the black passers and the game ended in a tablebase draw.

game 23, Halogen - Vajolet: Vajolet was a pawn up from the start. The game reached a QRB vs QRN position, Vajolet captured another pawn, exchanged queens and created a passer. The black king came forward, Halogen captured the passer but Vajolet reduced to a winning king and pawns ending.

game 29, ClassicAra - Fritz: Fritz was up a pawn from the start. ClassicAra sacrificed a knight, perhaps it thought it could attack the black king in the center. Instead Fritz attacked and forced ClassicAra to give more material. Fritz chased the white king to a mating net in the center of the board.

game 31, Booot - Nemorino: Nemorino was a pawn up in a BN vs BN position, with 3 connected passers on the king side. The game ended in an unusual opposite color bishop ending, black two pawns up, which was a tablebase win.

game 34, Halogen - Defenchess: Defenchess was a pawn up with a passer on the king side. It gave 3 pawns to open up the position and push the passer to the 2nd rank. The white king was exposed to attack and Halogen started to lose material. Defenchess captured a bishop for the passer, it continued to gain material and mate was unavoidable.

game 36, Pedone - Vajolet: Vajolet was two pawns up from the start, with the white king hiding behind a black pawn. Pedone gave a rook for a knight and captured the black pawn on the 2nd rank, while pushing a passer to the 7th rank. In a QRB vs QRR position Pedone seemed to blunder, allowing Vajolet to reduce to a winning B vs R ending. 

game 42, Nemorino - Fritz: Fritz was a pawn up from the start, Nemorino had an advanced passer in the center. The engines exchanged most pieces, Fritz captured the white passer and reduced to a rook ending with connected passers in the center. Nemorino managed to stop the passers but it was 3 pawns down by then and couldn't hold.

game 44, Arasan - Nemorino: Nemorino converted an unusual BNN vs Q imbalance.

game 50, Defenchess - Vajolet: Defenchess was better in the middlegame, it reduced to a rook ending with a pawn up. It then created a passer and pushed it forward to win.

game 56, Halogen - Fritz: Fritz was up a pawn in a RRN vs RRB position, with a pawn majority on the queen side. Halogen managed to capture a pawn and equalize on the queen side, Fritz cleared the white pawns on the king side and went 2 pawns up to win. 

game 57, Winter - Nemorino: The game reached a R vs N ending with Nemorino 3 pawns up. Winter couldn't block the advancing black pawns.

game 59, Vajolet - ClassicAra: ClassicAra gave a knight for two pawns to create a passer and a pawn majority on the queen side. Vajolet gave a knight to remove two pawns, the game reduced to a QR vs QR position with black a pawn up with a passer. After exchanging queens ClassicAra captured more pawns and the rook ending was a win. 

game 60, Minic - Defenchess: (Negative) evals increased steadily from the start. The game reached a QRB vs QRN position, the white pawns were weak on the queen side. Defenchess went two pawns up and created a passer, after 20 moves of slow improvement Defenchess connected a second passer. Minic tried to attack the black king and lost material, game over.

game 61, Defenchess - Booot: Defenchess was down a knight from the start. It captured two pawns and chased the exposed white king, but the position stabilized and Booot still had a piece advantage. The engines exchanged pieces slowly until only R vs RB were left. Booot gradually captured the white pawns, after exchanging rooks the game ended in a tablebase win.

game 65, Fritz - Winter: Winter was up a pawn after the start and (negative) evals steadily increased. The game reached a RRB vs RRB position, Fritz equalized material but its pawns were weak and its rooks played defensively. After exchanging a pair of rooks Winter went two pawns up, then it used its passers to gain material and win.

Standings after 11 rounds: Nemorino +3, Fritz Defenchess Minic +2, Pedone Booot Vajolet Winter +1, Halogen -1, Arasan ClassicAra -3, Seer -6. Eight engines are in the race for 2 qualification spots. The bottom 4 engines seem to be heading for relegation, perhaps Halogen still has a chance of surviving. Keep in mind that some of the openings were very biased, and the ranking may change when the reverse games are played.

game 68, Arasan - Winter: Winter grabbed a pawn in a RB vs Q position, this allowed Arasan to push a passer and force a perpetual check draw.

game 69, Fritz - Pedone: (Negative) evals increased from the start. Pedone went a pawn up and then a series of exchanges left only QR vs QR. Pedone captured a second pawn, Fritz had a passer on the 7th rank as a counter. After exchanging queens Pedone captured the passer and the rook ending was a win.

game 70, Nemorino - Vajolet: The game reached a 7-man queen ending which was a cursed win for black, that needs more than 50 moves without captures or pawn moves in optimal play. Vajolet eventually gave up, both engines lowered their evals and the game was adjudicated.

game 76, Vajolet - Fritz: The white DSB was trapped on the queen side, Fritz offered a knight for the trapped bishop and created an advanced passer. Vajolet managed to capture the passer but then Fritz created another, this time it was unstoppable. Fritz promoted to a queen and soon mated.

game 78, Winter - Halogen: The game reached a QR vs QR position with Halogen a pawn up. After exchanging queens Winter perhaps may have held, but after clearing the king side pawns the black king was better placed. Halogen drove the white rook away and captured a second pawn to win.

game 79, Booot - Winter: Winter was up a knight from the start, and this became a R vs BN imbalance. Booot created connected passers on the king side, it moved its rooks forward while most black pieces were stuck on the queen side. Winter captured one passer but the other reached the 7th rank. Winter had no effective counter, Booot gained material and won.

game 82, Fritz - Minic: Minic was up a pawn from the start. The white queen was active on the queen side, and when Minic shifted its pieces to the king side Fritz grabbed a pawn. However Minic reduced to a RN vs RB position and again went a pawn up. After exchanging rooks Minic created a queen side passer and Fritz gave its knight to stop it, leading to a tablebase win. A double win for Minic in this opening.

game 83, Nemorino - Defenchess: Nemorino grabbed a pawn and Defenchess trapped its rook, Nemorino traded the rook for a bishop. The game reached a RBN vs RRB position. Nemorino had 2 passers, after exchanging minor pieces Defenchess captured one passer. Both engines had one advanced passer but were unable to promote, after exchanging a pair of rooks Defenchess captured the white passer and won with its own.

game 87, Defenchess - Fritz: The game reached a QRN vs QRB position, Fritz with a passer in the center. For 25 moves Defenchess blocked the passer on the 3rd rank, Fritz went a pawn up and then pushed the passer once and exchanged rooks. Defenchess gave its knight to capture the passer, Fritz used the exposed white king to gain more material and win.

game 89, Vajolet - Halogen: Vajolet blundered in a seemingly drawn RB vs RN position, Allowing Halogen to exchange rooks and clear a path for an advanced passer on the queen side. By the time Vajolet captured the passer Halogen took over the rest of the board, it went two pawns up and won. A double white win in this opening.

game 92, Winter - Vajolet: Vajolet created a passer in the center, Winter countered with a passer on the 7th rank and threats on the back rank. Winter gave material to keep an attack going, Vajolet was able to defend. In the end both passers were gone and Vajolet was a rook up, game over.

Standings with 6 rounds to go: Pedone Minic Defenchess +4, Nemorino Booot +3, Fritz +2, Halogen Vajolet 0, Winter -2, ClassicAra -5, Arasan -6, Seer -7. There are still 6 engines in the qualification race. Pedone joined the leaders with 3 wins. Minic, Defenchess and Booot also improved with a +2 score. Halogen improved its chances of survival after it beat Winter and Vajolet, Winter is now in 9th place after losing to Vajolet as well.

game 102, Vajolet - Pedone: The game reached a RBN vs RBN position with black a pawn up and 3 connected passers on the king side. After exchanging bishops Pedone blocked Vajolet's attempt to push passers, then started to capture white pawns. Pedone was 3 pawns up after it cleared the white queen side pawns, the win was just a matter of time. Two black wins in this opening.

game 104, Pedone - Minic: Minic was two pawns up but its king side rook was trapped. Pedone increased the pressure on the black king and Minic did not have enough pieces to defend. Minic gave material but only postponed the mate.

game 105, Winter - Defenchess: Defenchess was three pawns up but it was behind in development and its king was uncastled in the center. Winter sacrificed two rooks for a knight and attacked, the black king had to run while the black pieces were unable to help. Defenchess lost a queen and bishop and Winter pushed a passer to the 7th rank. Winter continued to gain material until it mated.

game 108, Fritz - Nemorino: The game reduced to a QRR vs QRR position. Nemorino had a pawn majority on the queen side, it went a pawn up and reduced to a rook ending. Fritz moved its rook to the queen side and Nemorino captured a second pawn on the king side. Evetually Fritz lost its rook for a passer, game over. Two black wins in this opening. 

game 113, Defenchess - Pedone: Pedone was up a knight for two pawns from the start. The engines exchanged pieces until only rooks and knights remained, after a while Pedone reduced to a R vs RN position. Pedone captured black pawns patiently, making sure it kept a few pawns of its own alive. Eventally Pedone created an unstoppable passer and used it to win.

Standings with 3 rounds to go: Pedone +7, Nemorino +4, Minic Booot +3, Defenchess Fritz +2, Halogen 0, Vajolet Winter -1, ClassicAra -4, Seer -7, Arasan -8. Pedone almost surely ensured a qualification spot after 3 straight wins, beating both Minic and Defenchess. The second qualification spot and the 4th relegation spot are still wide open.

In round 20 only Fritz was able to win a game against Arasan, now at +3 half a point away from Nemorino in 2nd place.

game 123, Nemorino - Winter: Winter was up a pawn from the start but Nemorino managed to equalize. Nemorino captured two pawns using an attack on the black king, then reduced to a RRN vs RRN position and created connected passers on the queen side. Winter trapped and captured a knight but had to give back the piece to capture a passer. Nemorino still had a second passer in a double rook ending, enough to win. A double win for Nemorino in this opening.

In round 21 Booot, Nemorino and Pedone won, while Winter lost. Race for 2nd place: Nemorino +5, Booot +4, Minic Fritz +3. Race for 9th place: Halogen 0, Vajolet -1, Winter -2.

game 127, Booot - Defenchess: Booot was down a knight from the start, it was two pawns up and had a passer in the center. The engines exchanged pieces until only B vs BN remained. It took Defenchess more than 20 moves to capture all the white pawns, the game ended in a tablebase win. Two black wins in this opening.

game 131, Winter - Fritz: Fritz was up  a pawn from the start. It opened the king side and in a series of exchanges won a rook and two pawns for a bishop. The white king was exposed, Winter lost more material and was soon mated. Two black wins in this opening.

Booot lost in the last round, and once Nemorino drew its game it guaranteed 2nd place. Winter lost against Fritz and it is the 4th relegated engine.