Season 22 premier division, after RR4

Standings after RR4

Stockfish beat KomodoDragon as white and drew the reverse, the first decisive game pair within the top3 engines in this division. Stockfish leads ahead of KomodoDragon and Leela, with 1 point gaps between them. Can KomodoDragon finish ahead of Leela this season? Still too early to tell.

The top3 beat the bottom5 in 13/15 games as white in RR3+4. Stockfish and KomodoDragon had a perfect record, Leela only managed a draw against SlowChess and Stoofvlees. So far Leela failed to win 3 game pairs against the bottom5 engines, and this is the reason it is only 3rd. It needs to be perfect (or better) to catch up with the leaders.

Igel is last after it lost 3 game pairs within the bottom5 in RR3+4. rofChade, SlowChess and Stoofvlees had positive scores within the bottom5, they managed to move away from the relegation zone. ScorpioNN is in 7th place after a negative score, still close to the engines above it in the table and anything can still happen.

Interesting games

game 57, ScorpioNN - rofChade: The game reached a BN vs B position, ScorpioNN was down to its last pawn while rofChade had two. Evals were very high and still ScorpioNN couldn't find the win. The engines shuffled for almost 50 moves, ScorpioNN gave its knight in despair and took the draw.

game 58, KomodoDragon - SlowChess: All pieces were on the board when KomodoDragon's eval started to jump. After a few exchanges SlowChess moved its queen forward on the queen side to protect a knight, and KomodoDragon attacked the king side with its queen and a knight. It was a coordinated attack in a tight space, after 15 moves the outcome was a QRB vs QR position with a vulnerable black king and a white passer on the queen side. SlowChess lost its rook for the passer and the game ended in a tablebase win.

game 60, Leela - Igel: The game reached a BB vs BN position, evals increased despite the material balance. Leela reduced to an opposite color bishops ending and it was only one pawn up. However it was one of those rare occasions where an OCB ending is not a draw,  Leela had a passer on the queen side and it created a second passer on the king side. The black king stopped one passer, Igel lost its bishop for the other, and Leela had a last pawn to win.

game 61, rofChade - Igel: Evals increased as the engines exchanged pieces, the game reached a RRB vs RRN position with white a pawn up. rofChade had a passer on d6, by the time Igel captured it rofChade exchanged a pair of rooks and created another passer. Igel lost its knight for the passer and rofChade had enough pawns remaining to win.

game 63, SlowChess - Stoofvlees: The game reached a QBB vs QNN position, black was a pawn up but one of the knights was stuck in the corner. Evals jumped and SlowChess managed to move its queen forward and trap the cornered knight. After a B for N exchange Stoofvlees lost pawns to free its knight, but SlowChess attacked the black king and after a while mated.

game 65, KomodoDragon - rofChade: Queens were off early, evals increased slowly from the start. By move 32 KomodoDragon created a central passer and went a pawn up. The engines reduced to a RRN vs RRN position, rofChade pushed a passer on the king side but the white passer was more advanced. The engines traded the passers and a pair of rooks, KomodoDragon captured another pawn and that was enough for a win.

game 66, Stoofvlees - ScorpioNN: Stoofvlees gave a rook for a knight and then pinned a black bishop. ScorpioNN needed time to get its king out of the corner safely, Stoofvlees captured the bishop and the game reached a BBN vs RB position. ScorpioNN moved the rook forward and Stoofvlees trapped it, by the time the rook escaped Stoofvlees had an unstopppable passer. ScorpioNN lost its rook, game over.

game 70, SlowChess - Igel: Igel gave a rook for a bishop and pawn to stop an attack on its king. Evals increased as the engines exchanged pieces until RR vs RB remained. Igel had a central passer, and SlowChess focused on stopping it while not allowing the black king to approach. After 25 moves SlowChess managed to block the passer with its king safely, and after a few more moves it captured the passer and another pawn. SlowChess then pushed its own passer forward to win. 

game 72, KomodoDragon - Stoofvlees: KomodoDragon captured a pawn with its queen on the queen side. Stoofvlees saw an opportunity to attack on the king side, KomodoDragon did not interfere and instead gave a pawn and created a passer on the queen side. In a series of automatic moves Stoofvlees opened two files on the king side, it was sure it had a perpetual check draw at least, but it missed KomodoDragon's continuation. Evals immediately jumped, KomodoDragon stopped the attack and the game reached a QR vs QR position with white two pawns up and an advanced passer. KomodoDragon queened the pawn for a rook, the game ended in a tablebase win.

game 73, Stoofvlees - rofChade: Stoofvlees gave two pawns and did not castle its king, but it had an advanced queen side passer and the black king was exposed to attack. rofChade gave material to capture the passer, the game reached a RBN vs RN position with black 2 pawns up. After exchanging knights Stoofvlees traded pawns, it kept one last pawn to ensure the win. 

game 76, Stockfish - SlowChess: Stockfish castled long and then slowly prepared its attack on the king side, evals increasing quickly. When all pieces were ready on move 32 Stockfish opened the g file and then doubled its rooks there. After a few exchanges both engines saw the mate coming, in a coordinated attack first the black queen was captured and then it was mate.

game 79, KomodoDragon - Igel: For a long time evals did not change a lot and it seemed Igel was holding. After move 33 evals started to increase, KomodoDragon opened the h file and the black king became vulnerable. Igel had to give a rook for a bishop to avoid mate, the game reached a QRB vs QBN position. Igel tried to defend but couldn't protect everything, first it lost a pawn and then KomodoDragon exchanged queens and captured the knight. The game ended in mate a few moves later.

game 81, Leela - rofChade: Evals increased despite rofChade being a pawn up. Leela regained the pawn, the engines exchanged pieces until only RB vs RB remained and Leela went up a pawn. Leela had an advanced passer that was blocked by the black bishop. The engines exchanging rooks, leaving an opposite color bishops ending but a decisive one. The white king came forward to drive the bishop away and the black king was too far to help. Leela queened the passer to win.

game 83, Stockfish - KomodoDragon: See featured game below.

Standings after RR3: KomodoDragon +8, Stockfish +7, Leela +6, rofChade ScorpioNN -3, Stoofvlees SlowChess -4,  Igel -7. The top3 engines beat the bottom5 in 7/8 games as white, Leela only drew against SlowChess. Stockfish beat KomodoDragon, the first decisive game within the top3. If this becomes a game pair win this may be very important in the race for the superfinal. At the bottom Igel is struggling, after two losses as black and two draws as white within the bottom5. The remaining 4 engines of the bottom5 are potential candidates for the second relegation spot. 

game 85, rofChade - ScorpioNN: All pieces were on the board and evals started to increase, rofChade doubled rooks on an open file in the center. The king side opened and the black king was exposed, ScorpioNN captured a rook for a bishop and pawn. The engines continued to exchange pieces with a constant threat to the black king. Eventually rofChade regained a rook for a bishop and the game reached a QN vs QN position. rofChade pushed a passer to the 6th rank and exchanged queens, then captured the remaining black pawns to win. 

game 87, Stockfish - Stoofvlees: Evals didn't change until move 40, most pieces and pawns were still on the board and Stockfish had only 4 minutes on the clock. Stockfish pushed a pawn in the center and threatened to capture a knight. Stoofvlees was reluctant to move the knight, perhaps to protect the king side, and the pawn was pinned so Stockfish could not take immediately. The standoff continued for a few moves but in the end Stoofvlees moved its knight. A mate threat forced it to give a knight for two pawns, the engines reduced to a QB vs Q position. It took Stockfish another 20 moves to mate.

game 91, Stoofvlees - SlowChess: Evals slowly increased with very few exchanges, the first minor piece exchange was on move 25. Stoofvlees opened the king side and threatened the black king. SlowChess gave a rook for a bishop and tried to hide behind two connected white passers. It took Stoofvlees a while to find a way in, eventually it gave a rook for a knight and pawn. The advanced passers were too dangerous, SlowChess lost a rook for one. The game ended in a tablebase win. There were two white wins in this opening.

game 92, KomodoDragon - ScorpioNN: ScorpioNN didn't castle its king, it focused on the queen side with a queen and rook and was completely surprised when KomodoDragon opened the h file. ScorpioNN thought it was safe enough and it allowed a white rook to get to the back rank. ScorpioNN realized it was in trouble too late, its king had to run and KomodoDragon began gaining material with mate following.

game 96, Stockfish - Igel: Stockfish pinned a pawn in the center with a mate threat on the long diagonal, and used this to capture a pawn. After exchanging queens Stockfish pushed a passer on the queen side, Igel captured the passer and reduced to a RBN vs RBN position. Stockfish still had a back rank mate threat, Igel gave a rook for a bishop and tried to hold. Stockfish can be trusted to convert in these situations, though it took 30 more moves.

game 97, Stockfish - rofChade: The engines focused on the queen side, Stockfish had a 4 vs 3 pawn majority there and it slowly worked to create a passer. The game reached a RBN vs RBB position with a white passer on c6. rofChade captured the passer but gave a rook for a bishop. The black bishop pair tried to counter, Stockfish captured pawns and reduced to a N vs B ending 2 pawns up, game over.

game 99, Leela - ScorpioNN: Leela's eval started to jump after move 24 with most pieces and pawns still on the board. The black DS bishop was trapped on a7, Leela reduced to a QBB vs QBB position. Leela opened the bishop's trap and ScorpioNN preferred to lose the bishop rather than to allow Leela an advanced passer. Leela gave the bishop back and queened a passer anyhow, mate followed.

game 101, rofChade - Stoofvlees: Stoofvlees chose to give a bishop for pawns, it hoped a supported advanced passer would be a strong enough counter. rofChade's eval jumped, so did Stoofvlees' when it stopped to think for a minute. rofChade reduced to a QB vs Q position, then it used the exposed black king to capture pawns. The white king came forward and the game ended in mate. There were two white wins in this opening.

game 103, ScorpioNN - Igel: ScorpioNN had an eval advantage from the start, the center was blocked and the engines exchanged pieces and pawns very slowly. On move 33 ScorpioNN went a pawn up, after a while the game reached a RN vs RN position, ScorpioNN with a queen side passer. On move 60 only rooks remained, Igel captured the white passer but ScorpioNN created connected passers in the center. It took some time, ScorpioNN captured more black pawns, but eventually the passers moved forward and Igel couldn't stop them all, game over.

game 105, SlowChess - rofChade: There were very few exchanges after the start. Evals started to increase, there was a series of exchanges on the queen side and SlowChess moved a knight to e6. rofChade gave a rook for the knight and two pawns, the engines continued to exchange until only RB vs BN remained. SlowChess had a passer that rofChade had to cover, rofChade started to lose material and was eventually mated.

game 106, Stockfish - ScorpioNN: All pieces were on the board when Stockfish's eval started to increase while it gave two pawns. ScorpioNN thought it was fine and it continued to exchange pieces. Stockfish used the open files to attack on the king side, ScorpioNN thought for 12 minutes and realized it was in trouble. After a series of exchanges only QBN vs QR remained, Stockfish had a pawn majority on the queen side and it exchanged pawns to create a passer. Stockfish lost a bishop but after exchanging queens it cleared the path for a second passer, and that was enought to win.

Featured game: Stockfish - KomodoDragon
Premier division, game 83
Link to game on TCEC

Stockfish had an eval advantage from the start. There were very few exchanges and evals increased slowly. From move 16 the engines played a series of PV agreements, by move 28 queens and several minor pieces were exchanged, Stockfish created a passer in the center.

The engines continued to play through PV agreements in which Stockfish captured the a pawn. The engines exchanged a pair of rooks and the game reached a RBN vs RBN position.

Progress was slow, first Stockfish drove the black rook and bishop away. After exchanging a pair of pawns the white king came forward to the center of the board to protect the center pawns. Stockfish then targeted the pawns on the king side and captured a second pawn, creating an additional passer.

After trading bishop for knight Stockfish captured the last black pawn and saw mate in its PV. It did not push a pawn until move 82 (the d,e, and g pawns did not move since move 28! see boards above), by then there was nothing KomodoDragon could do to stop the passer. The game ended in a tablebase win.