There was a change in the running parameters of AllieStein (hash and treesize) starting from game 45. These parameters should have been changed from the start of the superfinal but were not by mistake. It is not clear what effect this paramter change will have, I have not observed a change in AlllieStein's performance, and it lost game 46.
Games 41-42 started with a 20-ply book sequence in the Neo-Gruenfeld defense, Goglidze attack variation, where the engines castled in opposite directions. In game 41 AllieStein pushed a pawn on the king side, it removed all the black pawns there and reached the 7th rank. Stockfish hid its king behind the white pawn and attacked on the queen side. The white king was exposed, Stockfish sacrificed a knight and chased the king. AllieStein gave the material back, the game reached a QRN vs QRN position on move 34. The game was almost adjudicated before the engines exchanged queens and Stockfish got rid of the white passer. AlllieStein went two pawns up but Stockfish was sure it was fine, the 50-move rule forced AllieStein to give a pawn back and the game ended in a tablebase draw on move 167.
In game 42 both engines were more focused on defense and both kings were relatively safe. Evals remained around 1 as the engines exchanges many pieces. AllieStein tried to attack the queen side, evals came down as the black pieces moved forward leaving their king less defended. AllieStein completely missed Stockfish's move 37, though it thought more than 3 minutes.
Evals immediately jumped as Stockfish opened a file on the king side. AllieStein gave a rook for a knight to lower the risk to its king. The game reached a QR vs QB position, both kings were exposed, evals were around 4.
Stockfish cleared the queen side pawns, then started to give checks. The white major pieces threatened a back rank mate, Stockfish only had to be careful not to allow a perpetual check draw on the other side.
Stockfish captured a pawn and created passers on the king side, these together with the mate threat were enough for a win.
Games 43-44 started in the Two Knights defense, Polerio defense variation. White was a pawn up and black had a development advantage. In game 43 Stockfish's eval was 0 almost throughout the game. Stockfish regained the pawn, after exchanging queens AllieStein castled long. Neither engine attacked, the game reached a RRB vs RRN position on move 35. Stockfish had a king side passer, AllieStein had a pawn majority on the queen side. AllieStein thought it had an advantage for a short while, after exchanging a pair of rooks and several pawns evals came down again. The engines played almost 50 moves of a 7-man position before ending in a tablebase draw. In game 44 Stockfish kept its king in the center, its eval came down to 0 quickly while AllieStein's eval turned negative. AllieStein had the initiative though Stockfish was a pawn up, the engines reduced to a QRB vs QRN position. AllieStein pushed a passer to the 2nd rank, Stockfish blocked it and then gave a rook for a knight, created passers of its own and exposed the black king. After exchanging queens the engines continued the B vs R ending for 30 more moves before reaching a tablebase draw.
In game 45 AllieStein pushed its pawns forward and did not castle, it had a space advantage and eval around 0.5, Stockfish's eval was 0. The white king walked to the king side while AllieStein pushed its king side pawns. AllieStein sacrificed a knight and exposed the black king, with the white queen and two advancing passers attacking. The white king was alone, Stockfish moved its queen forward and found a perpetual check draw after a rook sacrifice.
In game 46 both engines waited a while before castling, and the f file was open by the time both engines castled short. Stockfish's eval remained mostly under 1, the engines exchanged most pieces and pawns. By move 32 only QRN vs QRB remained with 3 pawns each.
Stockfish pushed the e pawn one square forward and slowly arranged its pieces so it could push it further to the 7th rank. AllieStein delayed as much as it could but could not stop the pawn from reaching e7. Stockfish's eval increased to around 2, its next plan was to force the black rook out of the queening square. AllieStein's hope was to counter with an attack on the white king. Stockfish thought AllieStein's 44th move was a mistake and AllieStein immediately agreed, both evals jumped.
Nothing could stop the knight move to c7, the black rook had to move and AllieStein lost its bishop after Stockfish queened the pawn. The extra piece was enough for a win, the game was adjudicated a few moves later.
There were almost no exchanges at the start of game 47, AllieStein's eval was over 1. AllieStein pushed pawns on the queen side and drove the black pieces back. The engines opened the queen side and exchanged a pair of knights, AllieStein's eval jumped to around 2 and Stockfish's eval jumped over 1. However, after AllieStein opened the king side and sacrificed a knight for pawns Stockfish's eval dropped back to 0. The game reached a RB vs RBN position, AllieStein was 2 pawns up with 3 connected passers. Stockfish was confident it could hold, indeed the game continued for 60 moves until AllieStein lowered its eval. The game ended in a tablebase draw. In game 48 again there were only a few exchanges and the engines played behind the pawn lines. AllieStein controlled an open file on the queen side, it gave a rook for a bishop and managed to move its queen forward to the white back ranks. This only led to an exchange of queens and a RRB vs RBN position. The game ended in a check repetition.
Stockfish's eval was 0 almost throughout game 49. After a series of exchanges only RBN vs RBN remained on move 27. AllieStein had a pawn majority on the king side, and it managed to create a passer out of this. Stockfish defended easily, evals remained low and the game ended in a tablebase draw. In game 50 the engines gradually exchanged pieces and pawns and evals came down to 0. On move 39 the game reached a rook ending, AllieStein's eval turned negative and it took a long time until its eval came back down. The game ended in a tablebase draw after 118 moves.
No comments:
Post a Comment