Season 20 league 3

Final standings

Minic, Nemorino and Seer advance to league 1. The race at the top was exciting and was not decided until the last round. Minic and Nemorino led the league from the start and finished tied at the top. Four engines fought for 3rd place, all 4 still had a chance of qualifying in the last round. The race ended with 3 engines tied, and Seer qualified by tiebreak.

Marvin and Pirarucu are relegated to league 3, Marvin lost more than half of its games, Pirarucu performed better but was never close to escaping relegation.

There were 3 qualifiers in this league due to Demolito not playing in league 2. This was formally declared only when the league was finished, though it was expected since the report was that there was no response from the engine's author.  

Seer advanced for the 3rd time after starting from the quallification league. This time it advanced as 3rd, so it would be a surprise it it managed to advance again unless there is a significant update.

In this season the tiebreak rules have been changed and r-mobility is used as a second tiebreak after head to head. This tiebreak was used to decide which of Minic and Nemorino finished first in the league, and it was almost needed for the 3rd place tiebreak. I am not comfortable with this rule. I understand the concept but I feel it is not visible enough. It cannot be calculated from the results of the games, and I haven't seen anything keeping track of this score on the website except reports on the chat. It is hard to know which engine has an advantage this way.

The 3 qualifiers will join the following engines in league 2:
Played in league 2 season 19:  Pedone, Vajolet, Winter, Wasp
Played in league 1 season 19: Defenchess, Fritz, Arasan

Interesting games

Game 11, Minic - Tucano: Tucano ignored the danger on the king side and captured a free pawn on the queen side with its bishop. Minic trapped the bishop and opened the king side with a knight sacrifice. Tucano did not have time to free its bishop, it avoided mate by giving material. The game reached a QR vs RR position, a win for Minic.

Game 18, Weiss - Topple: The black queen moved forward early, Topple managed to get it back safely and was up a pawn with a bishop pair advantage. Weiss then used its two knights to trap a rook in the corner, then it attacked the back ranks. After a while Weiss gained some material, and it was able to reduce to a winning R vs B ending.

Game 27, Weiss - Combusken: The engines shuffled in a closed position, then Weiss opened a file on the queen side and created an advanced passer. Most pieces were exchanged and Combusken was forced to lose a rook for a passer, game over. 

Game 35, Seer - Weiss: The game reached a drawn RN vs RB position, all pawns were captured except one black pawn in a 7-man tablebase draw. Then Seer blundered - no tablebase support - and exchanged the minor pieces, losing immediately by a 6-man tablebase win for black.

Game 36, Tucano - Weiss: In a RRB vs RRB position that looked drawn Weiss allowed Tucano to capture a pawn and create a passer. Tucano slowly pushed the passer forward, forcing Weiss to lose material and winning the game.

Game 38, Minic - Combusken: Minic attacked the king side from the start, the black king was exposed and Combusken exchanged pieces to save it. The game reached a Q vs R ending with black two pawns up, Minic won after 35 moves.

Game 45, Weiss - Nemorino: Weiss captured a pawn with its queen, and Nemorino immediately attacked the white king. Weiss lost a rook to save its king, enough for a win for Nemorino.

Scores after 9 rounds: Minic +4, Nemorino +3, Weiss Tucano Combusken +2, Seer +0, Topple Counter -1, Pirarucu -5, Marvin -6. There are 5 engines with positive scores in the qualification race. Pirarucu and Marvin lost more that half of their games with no win, together accounting for half of the decisive games so far.

Game 63, Topple - Weiss: The engines mostly shuffled for almost 100 moves, then evals started to increase. Topple found a way to reduce to a knight ending two pawns up and win.

Game 70, Seer - Combusken: Combusken missed a combination that let Seer capture a knight. Seer reduced to a winning RB vs R ending.

Scores after 15 rounds: Minic +6, Nemorino +5, Seer +4, Combusken +3, Weiss Tucano +2, Counter -2, Topple -3, Pirarucu -6, Marvin -11.  Now there are 6 engines racing for 3 qualification spots. Seer joins the leaders after 4 wins in 6 games. At the bottom Pirarucu and Marvin continue to accumulate losses.

Game 79, Nemorino - Combusken: Nemorino found a way to open the queen side and capture a pawn, then reduced to a winning rook ending two pawns up.

In round 16 Minic, Nemorino and Tucano won their games and Combusken lost. The scores at the top are: Minic +7, Nemorino +6, Seer +4, Tucano +3, Combusken Weiss +2. 

Game 81, Weiss - Tucano: Weiss was up a pawn with an advanced passer in the center. After reducing to a QR vs QR position Weiss captured two more pawns, then reduced to a winning rook ending.

Game 83, Combusken - Minic: Minic was busy defending its king side, Combusken captured two pawns on the queen side and created a passer. Minic gave a rook for a bishop to open the queen side and create some pressure on the white king, Combusken reduced to a winning QR vs QB position.

The scores at the top after round 17: Minic Nemorino +6, Seer +4, Combusken Weiss +3, Tucano +2. The top 2 are almost surely determined with one round to go. A 4-way race for 3rd place, head to head tiebreaks give Seer an advantage over Combusken, and Weiss over Seer and Combusken.

Game 89, Minic - Seer: Minic gave an early pawn and exposed the black king, then continued to give material during the attack which it then won back. The game reached a BNN vs R imbalance, Seer 3 pawns up. Minic used its piece advantage to attack the queen side while Seer pushed a passer on the king side. Eventually both engines queened a pawn and reduced to a QB vs Q ending, which was a win for white.

Game 90, Nemorino - Weiss: Nemorino opened the queen side and attacked the black king. The engines reduced to a QRB vs QRB position, Nemorino used mate threats to increase the pressure until it managed to capture the black queen for its rook. The game was over a few moves later.

Tucano won its last game, while Seer and Weiss lost theirs. As a result there is a 3-way tie for 3rd place including Seer, Combusken and Tucano. Weiss needed a draw to join this group in its last game. Seer qualilfies due to a win against Combusken.