Season 14 division 4, 3 rounds to go

The human championship is over, Carlsen won in the tiebreak easily.

Meanwhile in TCEC, season 14 division 4 will soon be over. With 3 rounds to go KomodoMCTS and rofChade will finish first and second. The third engine to advance to division 3 will be either Nemorino or Schooner, Nemorino has a lead of 1 point. The other race that is still active is for 8th and 9th place, the last spots to qualify for the cup event. Rodent, chess22k and Tucano all have a chance, Tucano has a 1 point lead over Rodent and chess22k.

Of the remaining 18 games there are 12 that involve at least one of the active races, including two direct head-to-head games Tucano - chess22k and Nemorino - Schooner. I will update this page as the games are played.

Nemorino - Rodent: There was an early Q vs RN imbalace. Nemorino's eval was around 2 for a long while, both engines had an advanced passer they couldn't push forward. Nemorino found a way to capture the black passer, and then opened the king side and reduced to a won tablebase position.

Demolito - Schooner: The game was mostly quiet, reached a RR vs RBN position and ended in a repetition draw.

chess22k - ScorpioNN: As expected chess22k had no trouble winning this game, this time ScorpioNN did not crash.

Wasp - Tucano: Evals were close to 0 until Tucano chose to give a bishop for 3 pawns. Wasp developed a strong attack on the black king, Tucano exchanged pieces until only RB vs R were left and all the white pawns were gone. Wasp forced Tucano to give its rook for a bishop, resulting in a won endgame.

Two rounds to go. Nemorino is 1.5 points ahead of Schooner, Schooner will need a miracle to reach 3rd place. Rodent is a point behind chess22k and Tucano, it still has a small chance to reach 9th place.

Tucano - chess22k: Tucano was better after the opening, chess22k held the position for about 25 moves. Tucano went a pawn up and then exchanged pieces until only BN vs BN remained, with a white passer on the 7th rank. chess22k gave a knight for the passer, losing the game.

Schooner - KomodoMCTS: Black was a pawn up from the start. The game reached a B vs N ending with many pawns. KomodoMCTS was a pawn up but it was a doubled pawn. The engines shuffled for a while, then exchaged a few pawns. KomodoMCTS' eval was over 4 but it couldn't find a way to convert. KomodoMCTS gave a pawn to avoid the 50-move draw, then its eval started to climb again. It was over 6 and still KomodoMCTS couldn't fin a way to win, the game ended in a repetition draw. It is quite possible KomodoMCTS had a winning position in this game but couldn't find it.

rofChade - Nemorino: Nemorino defended in closed position. A series of exchanges opened the position and ended with only RBN vs QN remaining. rofChade outplayed Nemorino, it attacked the black king and then captured the knight. The endgame was slow, rofChade slowly pushed a pawn that in the end guaranteed the win.

Rodent - pirarucu: All pawns remained on the board and the engines shuffled until reaching a draw.

One round left. Schooner's miraculous draw and Nemorino's loss mean that Schooner still has a chance, it needs to beat Nemorino in their last game. Tucano is a point ahead of chess22k and 1.5 points ahead of Rodent. Tucano is sure of a top-9 place, Rodent and chess22k are still fighting.

Winter - Rodent: Rodent had no problem beating Winter quickly.
.
Nemorino - Schooner: Schooner needed a win, but it was a pawn down after many early exchanges. Nemorino went on to capture a second pawn and reach a winning endgame. Nemorino qualifies for division 3.

Demolito - Tucano: Irrelevant.

chess22k - Wasp: Evals were low in a closed position. Then the king side opened up and  chess22k did not survive Wasp's attack. chess22k finishes 10th, and Rodent is the last engine to qualify for the cup event.

Final Crosstable

 

Season 14 live blogging, Monday Nov 26th

Division 4 is in the 3rd RR of 4, and the engine ranks in the table are more or less determined. The first 3 will qualify for division 3, and they will be KomodoMCTS, rofChade and Nemorino. The first 9 will participate in the cup event of season 14, Winter and ScorpioNN will probably be last but Tucano still has a chance to reach 9th spot, with Rodent and chess22k above it in the table. If ScorpioNN crashes again it will be disqualified and removed from the table, but it lost all its games (except a draw against Winter) so this will have no effect on the table.

Now playing are Schooner and Wasp, round 29. Meanwhile in the Carlsen_Caruana championship match the 12th game is about to start, so I will keep an eye on that in about 20 minutes.

move 10: The engines followed theory of this opening, the position looks drawish. White has an isolated queen pawn, black will probably castle soon. Schooner had a long think on move 10, but no effect on the eval.

move 15: The rooks are moving to the center, Schooner put a rook on the c file which has no pawns but is full of pieces. Wasp's LS bishop is still blocking the queen side rook, evals climbing a little.

move 20: Schooner's pieces look better placed. Wasp tried a king side attack, the engin.es exchanged bishops and the white knights control the entry squares for the black queen so the attack cannot proceed. Finally Wasp moved its LS bishop, connecting the rooks. The bishop still looks awkward.

move 25: Evals are coming down, though the position seems to have potential with many pieces and an open center. Schooner thought long again, trying to find a plan. Wasp's eval drops to 0 and then negative, as it attacks the queen side.

move 35: After several exchanges Wasp is a pawn up and evals are negative but still low. Wasp has a queen side passer while its king is a little exposed. I still think Schooner can hold.

move 45: Schooner captured the black passer and material is equal, all the pawns are on the king side. The evals are not going anywhere, a few more exchanges and it will be a clear draw. Only QRN vs QRB remain.

move 50: The engines exchanged a pair of rooks, evals are in the draw rule range. This will be a draw unless there is an unusual blunder. I'm shifting my attention to the human match, so I'll leave this game now.

Season 14 live blogging, Monday Nov 19th

Season 14 has started, and I am not following it too closely so far. There are 12 engines in division 4, most of them are new to TCEC. The division is a 4RR event, so 264 games. The games are short so I cannot view them all. The division has been restarted several times due to problems with the GPU-CPU server connection and with the 2-move openings. On top of everything the Carlsen-Caruana world championship is being played at the same time. To sum up, the division is long, not too interesting for me, and I have other interests right now. Division 3 will be more interesting, with new Leela starting its climb to the premier division.

We join the rofChade - chess22k game. This is round 7 of 44 in the division, according to their performance so far in the division I would say rofChade is the favorite.

move 10: The engines are following a popular line in the Gruenfeld defense. On move 9 rofChade took a lot of time to think, over 5 minutes, but played the popular move in the end - no surprise yet. According to Lichess there are several options for black on move 9, chess24 chose the third popular one. Evals are close to 0.

move 15: chess22k chose a less popular line on move 11, still in book. rofChade's eval increased to 0.46. There are only a few games left in the database on move 12, none on move 14. rofChade has a strong pawn line in the center, both engines look solid. chess22k has a pawn majority on the queen side. On move 14 it tried to attack the white center, rofChade did not exchange.

move 20: chess22k wants to exchange the DS bishops, rofChade has other plans. Evals are climbing over 0.7. chess22k moved a knight forward and back, can't be a good idea to give tempi like that. Now rofChade is thinking about exchanging bishops and chess22k avoids this. chess22k is not doing anything, does rofChade have an effective plan?

move 25: rofChade shifts to the queen side and pushes the a pawn. Its eval drops a little while chess22k's eval increases over 0.9, then drops back. The knights are exchanged, the bishops and rooks need more space to be effective. The engines open the a file, the center is still closed.

move 37: Evals are trending down, chess22k sees exchanges coming, perhaps the DS bishops will be gone after all. In a long PV agreement the engines start to exchange pieces, only QRB vs QRB remain. chess22k tried to exchange the remaining rooks but rofChade said no. Evals stay constant under 1.

move 45: rofChade has a central passer, I don't see how it can push forward. The engines are shuffling, this may take a while.

move 60: The shuffling continues, this will go to a 50 move draw unless the evals come down to 0. I hope rofChade does not blunder to avoid a draw.

move 70: The draw counter reset after rofChade pushed its passer the the 7th rank. rofChade's eval jumped to about 1, chess22k chose to let the passer queen and exchanged down to a Q vs RB ending. Was this a blunder?

move 80: Both engines are not using tablebases, however it seems that rofChade is winning according to the Stockfish commentary. The white pawns on the king side are starting to march, chess22k cannot stop them and its king is going to be in trouble soon.

move 90: Game over. chess22k was the one to blunder, it should have continued to shuffle.

Season 13 superfinal, games 93-100

Stockfish is the season 13 winner. It won the superfinal 16-6 with 78 draws.
Stockfish added 3 more wins in the last 8 games.

The engines castled in opposite directions in game 93, then pushed pawns facing their opponent's king. The black pawns on the queen side made contact with the white pawns, and this locked the queen side. Komodo opened a file on the king side and created a central passer. Stockfish captured two black pawns on the queen side and went a pawn up, while creating a queen side passer.


Evals changed very little for a long while. The pawns did not move, Stockfish blocked the black passer and it did not push its queen side pawns that protected its king. Komodo saw an opportunity to gain a pawn and equalize material, evals jumped as Stockfish used the the time to push pawns forward and create an advanced passer in the center.


Evals climbed rapidly, Stockfish gave a rook for a bishop and removed two black passers. The engines reduced to a RBN vs RRN position, with strong queen side pawns for Stockfish.


Komodo gave its knight to remove one of the white passers, it couldn't stop the remaining two passers without losing material and the game.
Stockfish's lead is 8 points after this game, with 7 games left it secures the win in the superfinal.

There were many early exchanges in game 94, with only RRB vs RRB remaining on move 22. Komodo was a pawn up and evals were close to 0. Stockfish won the pawn back and the engines exchanged a pair of rooks. The game was adjudicated by draw rule when the engines stopped capturing pawns. Another minimatch win for Stockfish.

Games 95-96 started with a King's Gambit variant where white sacrificed a knight for a pawn and opened the black king side. In game 95 Komodo moved its king side rook so that it couldn't castle short. Stockfish immediately went on the attack and its eval jumped over 2.5. It lined up a rook and queen on the open f file and threatened a mating attack.


Komodo exchanged pieces to stop the attack on its king. It gave the piece back and the game reached a RRN vs RRN position on move 23. Evals continued to climb fast, Stockfish went two pawns up with passers in the center and on the king side.


Komodo captured the passer in the center. The engines exchanged a pair of rooks, reaching a RN vs RN ending which was hopeless for black.


Stockfish pushed the h pawn forward and the game was adjudicated quickly.

In game 96 stockfish castled short even though that left its king exposed in the corner. Komodo did not attack directly, allowing Stockfish to develop the queen side and add protection for its king. Evals came down, Stockfish gave a rook for a bishop resulting in a R vs BN imbalance. Komodo had a central passer which got as far as the 7th row. After exchanging queens the game was adjudicated in a drawn RR vs RBN position. Komodo lost this minimatch despite the substantial book advantage. Stockfish made it look so easy in the previous game, but it managed to hold as black. The lead increases to 9 points.

There were only a few exchanges in the opening of game 97. There was a small hole on the king side which made the white king vulnerable. The engines opened two files on the queen side, Stockfish had more pieces there and its eval was more than 1.5. The first piece exchange was on move 43, Komodo sacrificed a knight for a pawn on the king side and threatened the white king. The engines started to shuffle and Stockfish's eval came down. After a few exchanges both kings were exposed. Stockfish captured pawns and created passers in the center, Komodo threatened mate and Stockfish ended the game by perpetual check. 

Komodo pushed pawns on the queen side in game 98, Stockfish pushed pawns on the king side and the center was blocked by long diagonal pawn lines. Komodo focused on the queen side, it created an advanced passer. At the same time it gave a bishop for a pawn on the king side and evals became negative. The engines exchanged most pieces, did the advanced white passer compensate for the piece?


Evals did not change for a while, the engines exchanged a pair of rooks and only RB vs RBN remained. Komodo's passer stayed on the 6th rank, Stockfish also created a passer on the queen side.


Stockfish's idea was to move its king to the queen side, where it could be more useful. It was a long journey and it took a while, the evals climbed gradually. Komodo could grab the free h pawn but that would open its king to attack. Komodo preferred to hide its king behind the black pawn.


Stockfish had enough strength on the queen side to get rid of the white passer and start pushing its own. The extra piece became a deciding factor, Komodo couldn't stop the black passer without losing material. This is the 4th minimatch in a row that Stockfish wins, it leads by 10 points.

The engines castled in opposite directions in game 99. The engines made early attempts to attack their opponents' king, but after exchanging several pieces including the queens these attacks were over. Stockfish was a pawn up, evals came down to 0 and the engines shuffled until adjudication. In game 100 Komodo sacrificed a knight for pawns and opened the black king side, exposing the black king. Evals were at 0, Komodo pushed pawns on the king side and the black king walked to the queen side. The engines reduced to a Q vs QB ending, a white passer reached the 7th rank and Stockfish ended the game in perpetual check.

Season 13 superfinal statistics

Draw rate, wins

 
Final draw rate was 78%.

Game termination

The three most common game termination causes were:
52% - TCEC draw rule
22% - TCEC win rule
15% - SyzygyTB

Moves per game


Median= 56.8
Average= 66.5

There were 14 games longer than 100 moves, 3 games longer than 150 moves. The longest game was 197 moves (game 6, draw). 

Time per game (hours)

 
Median= 3:52
Average= 3:52

Openings

There were variable length book openings in this stage chosen by Jeroen. The first letter of the ECO codes was distributed as follows:


If we use the opening 'family name' (using format FAMILY_NAME: VARIANT....) the top 3 are:
Sicilian - 14 times
King's Indian - 10 times

French - 8 times

The engines had little freedom to choose the opening variant, depending on the length of the book sequence. In fact all but one of the game pairs repeated the same ECO code and opening variant twice. Games 97-98 were two King's Indian variants that differed on move 10, with ECO codes E98 and E99.

Reverse pairs, wins

 
There were no openings with a 2-0 result, and only one opening with a biased 1-1 result (games 85-86, Old Indian, Tartakower (Wade) variation). 

Reverse pairs, same moves 


Pairs of reverse games diverged very quickly, 68% of the pairs diverged at most after 1 move. The longest repeated move sequence in a game pair was 18 plys long (games 37-38, QGA, Linares variation, two draws).  

Season 13 superfinal, games 87-92

After 92 games Stockfish leads 13-6 with 73 draws.
Stockfish's lead is 7 points with 8 games remaining in the superfinal.

There were only a few exchanges before move 24 in game 87. Stockfish went a pawn up and after a series of exchanges only RBN vs RBN were left. Komodo got the pawn back and the engines started to shuffle. After exchanging a pair of knights and a few pawns Stockfish was again a pawn up, the shuffling continued. Stockfish lowered its eval only when the draw counter was close to 50, and adjudication followed.

Komodo had a small eval advantage at the start of game 88. There were only a few exchanges, evals started to increase when Stockfish pushed pawns on the king side. Komodo's pieces retreated, its king's position looked solid while the black king was exposed.


Komodo gave a pawn on the queen side, then exchanged a rook for a knight and captured two black pawns on the king side. Evals increased over 1, Komodo controlled the king side and the black king looked vulnerable.


Stockfish exchanged pieces, giving back the material until only RB vs RB were left. Komodo had two passers on the king side while Stockfish had a passer on the queen side. The white rook and black bishop were trapped by pawns on the queen side, the engines could only play on the king side. 


The black rook was not strong enough to stop the pawns from advancing and the white king from infiltrating the queen side. Komodo had time to capture the black passer, it then secured its king side pawns. Stockfish opened the queen side and freed its bishop, this also freed the white rook and created another passer and a won ending for Komodo. A minimatch win for Komodo, reducing Stockfish's lead to 6 points.

Stockfish had an eval around 1 in game 89. It gave 3 pawns for a knight and opened the center, after exchanging queens evals started to come down. The engines reduced to a RB vs R ending, evals were at 0 and the game was adjudicated by the draw rule. In game 90 the center stayed closed and there were a few exchanges. The engines opened a file on the queen side and exchanged a pair of rooks, then started to shuffle. Komodo gave a knight for pawns to open the queen side and create a passer. Stockfish gave the knight back and moved its queen and a rook to the white back ranks. After a series of exchanges only QB vs QB remained, evals came down and the game was eventually adjudicated after most of the pawns were captured.

Games 91-92 started with a long 35-ply book variant of a closed Ruy Lopez. In game 91 Komodo sacrificed a knight for two pawns and opened the center. Stockfish countered by giving a rook for a bishop and opening the black king side. Komodo was ahead on material yet Stockfish's eval was close to 3.


The black king was exposed and in danger of mate, there were not enough black pieces available to defend it. Komodo gave back a rook for a bishop to remove one of the attackers. This left QNN vs QBN on the board.


Komodo's king walked to the queen side to get away from the white pieces, Stockfish captured a pawn in the process. The engines exchanged a pair of knights, evals continued to climb despite the small material difference.


The black king was still exposed to checks, this gave Stockfish extra queen moves. The h pawn started to march, Komodo couldn't stop it without losing its bishop and the game.

Game 92 was quiet, evals stayed low and the engines gradually exchanged pieces until only RN vs RB were left on move 34. Evals were 0 as the engines captured the pawns, the game ended with all the pawns gone in a tablebase draw. Stockfish extends the lead back to 7 points.
 

Season 13 superfinal, games 79-86

After 86 games Stockfish leads 12-5 with 69 draws.
The draw rate continues to decrease, now at 80.2%. The sequence of decisive minimatches ended with two openings the engines drew, but then there was the first opening with a biased 1-1 result. Stockfish's lead is 7 points with 14 games left.

Stockfish had an eval over 1 at the start of game 79. The engines castled in opposite directions and evals started to increase. Stockfish had a space advantage and Komodo's pieces were pushed back and defensive. Stockfish pushed pawns on the queen side and threatened the black king.

A series of exchanges eliminated most pieces. Komodo gave a bishop for a pawn and only QRB vs QR remained on move 30. Komodo's king was hiding in the corner, most of the black pawns were invisible to the bishop. Evals were high but Stockfish still had to find a way to win.

Komodo's only hope was to use the exposed white king to threaten mate or a perpetual check draw. Stockfish had to be careful,  it managed to get its king to a square where it couldn't be attacked and brought the rook forward.

Komodo exchanged queens, it was 3 pawns up but the RB vs R ending was a win for Stockfish.

Komodo had an eval of about 0.5 after the start of game 80. There were a few exchanges, the last one on move 17 when Komodo won a pawn. Stockfish doubled rooks in an open file on the king side, Komodo blocked it with a knight. The engines started to shuffle, with a few pawn moves that locked the queen side. Evals stayed around 1, and only came down when the 50 move draw was close. This was the 5th decisive miniatch in a row, Stockfish extends its lead to 7 points.

Stockfish had an eval advantage less than 1 from the start of game 81. There were no exchanges until move 21, the center was blocked and the engines played behind their pawn lines. The engines opened a file on the king side, Komodo doubled its rook there and its eval turned negative for a while. Stockfish created a passer on the queen side and evals returned to 0. After a few exchanges the engines started to shuffle until adjudication. In game 82 Stockfish opened the center and gave a rook for a knight and two pawns. Evals stayed low, the engines exchanged down to a QRR vs QRN position. The rooks did not have open files and the engines again shuffled until adjudication.

Stockfish started game 83 with an eval around 1. Komodo gave a rook for a knight and pawn, then a series of exchanges left only RRB vs RBB on move 17. The engines started to shuffle, with a few pawns moves that reset the 50 move counter. Stockfish's eval came down on move 115, it took 20 more moves to adjudicate the game. In game 84 Komodo's eval started around 0.5 and gradually increased. Komodo castled long and Stockfish kept its king uncastled in the center. Stockfish pushed pawns on the queen side and weakened the white king's defenses. In a series of exchanges Komodo gave a rook for a bishop, only QRB vs QRR remained. The exposed black king compensated for the lost material, evals were over 1. The black king marched to the queen side, leaving Komodo to capture pawns. Stockfish gave the material back and reduced to a queen ending one pawn down. Evals came down and the game was adjudicated a draw.

Stockfish started game 85 with an eval over 1 that gradually increased. The engines opened the center and castled in opposite directions. Stockfish had the bishop pair advantage in an open position, its pieces seemed to be preparing an attack on the king side. Komodo had open files for its rooks on the queen side.


Komodo's queen side attack was weak and nothing came out of it. Stockfish won a pawn while losing one of its bishops, evals continued to increase steadily. The engines exchanged down to a double rook ending, Stockfish captured another pawn and was two pawns up.


Stockfish had passers on both sides. The 3 connected passers on the queen side were also guarding the king so Stockfish didn't push them forward immediately. First it focused on the king side, exchanging pawns and gaining a third pawn in the process.


The material advantage was more than enough to secure a win for white.

In game 86 evals were around 0.5 from the start. There were no exchanges until move 16, the center was blocked and both engines kept the kings uncastled. Komodo pushed a pawn on the king side and made a hole in the pawn line. Stockfish had already moved its queen side rook, it decided to move its king and not castle. Komodo gave a rook for a knight and created a central passer, evals jumped over 1.


Komodo found safety for its king by castling long. On move 29 the engines had a long 15 move PV agreement which they played out. Stockfish gave the rook back for a bishop, the engines exchanged queens, Komodo won a pawn and created a second passer on the queen side. After a few more exchanges only RNN vs RBN remained, Komodo with two pawns and Stockfish down to one.


This is the sort of position that only chess engines can understand, humans can stare at the evals and try to figure out what is going on, preferably using a strong chess engine... For a long while the evals fluctuated, Komodo tried to strengthen its queen side, support its pawns and allow them to move forward. Stockfish blocked the white pawns while protecting its remaining pawn. Eventually Komodo captured the black pawn and exchanged a knight for a bishop. Evals started to increase again.


The RN vs RN ending was still very tricky. It took Komodo almost 40 more moves before the game was adjudicated. The 50 move counter was down to 10 as the pawns still hadn't advanced, the PV showed that a win was still very far off yet both engines agreed it was inevitable.
This was the first opening of the superfinal with a biased 1-1 result. The book was only 4-plys long, the two games had very different characteristics. I would argue that the engines had a lot of influence on the result, more than the opening itself.

Season 13 superfinal, games 75-78

After 78 games Stockfish leads 10-4 with 64 draws.
There were 4 decisive minimatches in a row, Stockfish is still 6 points ahead. Komodo's last win was unusual, it played with the black pieces in an opening that had a small bias in favor of white.

White was a pawn up from the start in games 75-76, black was slightly more developed.
Stockfish had a small eval advantage at the start of game 75, Komodo's eval became negative after Stockfish moved its king without castling. Stockfish's king side was not developed, its eval became negative over 1 after Komodo created an advanced passer in the center.

Komodo got the pawn back. Stockfish had several opportunities to exchange queens but it decided not to. Evals steadily increased, Komodo's passer did not advance but it was well protected and Stockfish couldn't get rid of it. Stockfish finally cleared a path for its king side rook to get out of the corner.

Komodo was in control, before long it captured a pawn on the queen side and created a second passer. The white pieces could hardly move, Komodo gave a rook for a knight and Stockfish couldn't stop both white passers. The game was adjudicated before Stockfish was forced to give a rook for a passer.


In game 76 Komodo had a small eval advantage, evals stayed positive and low. Komodo castled short while Stockfish pushed pawns on the king side. Komodo gave the pawn back as the engines opened the queen side and evals became 0. After exchanging queens only RRB vs RRB remained and the game was adjudicated by the draw rule. Komodo wins another minimatch, this time in black in an opening that seemed to be favoring white.

Stockfish started game 77 with an eval around 1. On move 15 the white queen captured a pawn on the queen side, this allowed Komodo to attack the queen but Stockfish did not think the pawn was poisoned. Stockfish then captured a second pawn, Komodo had open files for its rooks and a bishop pair but did that compensate for two pawns?

Komodo got one pawn back, for a while both engines had advanced passers that looked dangerous. In a series of exchanges the engines captured their opponent's passer and reduced to a rook ending, Stockfish still a pawn up.

Stockfish captured the black passer on the d file while making sure that its a pawn was safe. The white king walked all the way to the queen side, Komodo pushed its king side pawns in desperation.

There was no doubt Stockfish was winning, the game was adjudicated after Komodo lost another pawn.

Komodo attacked the black king at the start of game 78, nothing came out of the attack and evals came down to 0. In a series of exchanges Stockfish gave a rook for a knight and two pawns, while exposing the white king. The game reduced to a RRB vs RBN position, Stockfish advanced passers on the king side but had to defend its king under threat by the black rooks. The engines exchanged down to a N vs R ending and a tablebase draw. Stockfish wins this minimatch and the lead goes back to 6 points.

Season 13 superfinal, games 71-74

After 74 games Stockfish leads 9-3 with 62 draws.
Two decisive minimatches in a row, one win per engine, Stockfish's lead is still 6 points.

The engines castled in opposite directions in game 71. Stockfish's eval was over 1 as it concentrated its pieces on the king side. Komodo started a series of exchanges in which it gave a rook for a knight and pawn. After exchanging queens only RRB vs RBN were left.


Evals constantly increased though the material difference was not that significant. Stockfish brought its two rooks forward, then it gave a rook for a bishop and pawn. Material was equal, but now Stockfish had an advanced passer on the queen side and its eval was over 3.


Komodo gave its knight to get rid of the passer, leaving a RB vs R endgame with black two pawns up. Stockfish protected its pawns with the rook and used its bishop to attack the black pawns on the king side.


The game was adjudicated after Stockfish cleared both the black king side pawns. The h pawn became a passer and Komodo could not stop it without losing material.

Queens were off early in game 72 and evals stayed low. There were many early exchanges, Komodo was a pawn up for a while but Stockfish equalized. The engines reduced to a RB vs RN position, Komodo was again a pawn up but only got a drawn rook ending. Stockfish's lead is now 7 points.

The engines castled in opposite directions in games 73-74, white castled long. In game 73 Komodo gave a piece on the king side, removed the white pawns in the center and threatened the white king on the queen side. Stockfish exchanged queens to stop the attack, then opened the king side while Komodo regained the piece and was a pawn up. Evals were 0, yet the action continued. Stockfish gave a rook for a knight to create a passer on the king side. The engines reduced to a N vs R position, Komodo captured the passer and the game ended in a tablebase draw.

Stockfish was a pawn up early in game 74, though Komodo had a small eval advantage. Stockfish had an open file on the queen side, not enough to put the white king in danger. Evals increased over 1 as Komodo attacked the king side. After exchanging a pair of rooks and opening files on the king side the black king had to run to the other side for safety.


The engines had long PV agreements that were played out. The black king side pawns were left unprotected and Komodo was soon a pawn up with a passer. Evals were over 2 after queens were exchanged, with NN vs BN remaining.


Evals continued to increase and both engines saw Komodo was winning. It took a few moves for it to place the knights and then Komodo pushed a central pawn forward, creating a second passer.


The game was adjudicated, Stockfish's PV showed that the win was still not obvious, white could remove the black pawns with two passers left. Komodo gets its 3rd win, Stockfish's lead is back to 6 points.

Season 13 superfinal, games 59-70

After 70 games Stockfish leads 8-2 with 60 draws.
Stockfish extends its lead to 6 points, with 30 games remaining and the current draw rate it is very unlikely that Komodo can close this gap.

Stockfish started game 59 with an eval over 1 that gradually increased. The engines castled in opposite directions, Stockfish pushed pawns on the king side and brought a rook forward facing the black king. Komodo exchanged two knights for the rook and two pawns.


Komodo had a passer in the center and a pawn majority on the king side, Stockfish had a pawn majority on the queen side. Evals increased for a while, Stockfish's eval reached almost 3, then stopped climbing. The white pawns on the king side were exchanged and Komodo had 3 passers, yet evals suggested Stockfish was better.


Komodo saw an opportunity to exchange queens and took it. Stockfish thought this was a mistake, it captured the two black queen side pawns and its eval jumped. All the pawns were passers, both engines pushed a passer forward and Stockfish was winning the race.


The extra white piece became crucial. Komodo had to keep one rook on the white passer, and its king and other rook couldn't protect all the black pawns. Stockfish captured the black passer on h3, and the game was adjudicated before Komodo lost more material.

In game 60 there were many early exchanges and only RRN vs RRN were left on move 24, Stockfish a pawn up. Evals were 0, Komodo got the pawn back and the game reduced to a RN vs RN position with only one pawn left for each engine, another draw. Stockfish's lead is now 6 points.

The engines castled in opposite directions in game 61, both kings were not fully protected by pawns. Stockfish's eval increased over 1 and came back down. In a series of exchanges Stockfish exposed the black king and won a pawn. The game reached a QB vs QB position and Stockfish forced a draw with perpetual check. In game 62 both engines castled long, the king side was blocked. After a few exchanges the engines started to shuffle, it took more than 100 moves for Komodo to lower its eval for adjudication by the draw rule. 

In game 63 Stockfish had an eval of 1 from the start. It gave a pawn on move 13 and this started a series of exchanges that left only RBN vs RR on move 22. A few moves later the evals came down to 0. Komodo pushed a passer to the 2nd rank, Stockfish lost a knight to capture it and the game was adjudicated soon after that. In game 64 evals stayed low. The engines exchanged rooks through an open file and only QB vs QN remained on move 25. After exchanging queens the engines shuffled until adjudication.

Stockfish had an eval around 1 from the start of game 65. The center was blocked and there were no exchanges until move 20. The engines gradually exchanged pieces while keeping most of the pawns, evals came down when only RRB vs RRN remained. The game continued for 50 more moves and ended in a tablebase draw. In game 66 both engines kept their pieces behind their long pawn lines. After all the knights were exchanged the engines began shuffling. After opening the king side a little the engines exchanged down to a RB vs RB position, it took another 50 moves for a draw rule adjudication.

In games 67-68 the engines castled in opposite directions and each pushed pawns facing the opponent's king. In game 67 Stockfish's eval quickly increased over 1. Komodo's queen side attack was faster, weaking the white pawns guarding the king. Stockfish exchanged pieces and hid its king behind a black pawn. Komodo gave a pawn to open a file in the center and evals started to come down. The game reached a QR vs QR drawn position. In game 68 queens were exchanged early and evals stayed low. Stockfish managed to open a file on the queen side but the white king was not in real danger. The engines exchanged down to a RRB vs RRB position with Komodo a pawn up, the game ended in a repetition draw.

Games 69-70 started with black a pawn up. Evals stayed low throughout game 69. There were many early exchanges, Stockfish regained the pawn and only BN vs BB were left on move 27. The game ended quickly in a tablebase draw. In game 70 Stockfish held on to its pawn advantage and its (negative) eval started to increase. Stockfish pushed a queen side passer, Komodo countered by creating its own queen side passer. Stockfish's eval was more than 1.5 as both engines struggled to protect their passer and attack the opponent's passer. In a series of exchanges both passers were gone and the game reached a rook ending, 3 vs 2 pawns on the king side. Stockfish's eval remained high, it had a passer but it couldn't push it beyond the 4th rank. The game ended in a 50 move draw.

Season 13 superfinal, games 51-58

After 58 games Stockfish leads 7-2 with 49 draws.
Stockfish added two wins, while holding Komodo to a draw in both reverse games.

Stockfish castled long in game 51, then pushed its king side pawns. Komodo kept its king in the center and counter-attacked on the queen side. Evals came down to 0, Komodo felt safe to castle after several exchanges. When a black passer reached the 2nd rank Stockfish hid its king behind it and evals jumped again, but only for a short while. Komodo sacrificed a bishop to expose the white king, and in a QRN vs QR position this was enough for a draw. In game 52 Stockfish castled short immediately and then exchanged pieces in the center. Evals stayed low, Komodo opened the king side and the black king hid behind a white pawn. The engines reduced to a RB vs RB position and the game was adjudicated by the draw rule.

In game 53 Stockfish gave a pawn and trapped a bishop at the start. A series of exchanges led to a BN vs R imbalance on move 22. After exchanging queens the game reached a RBN vs RR position with Komodo a pawn up. Stockfish's eval was close to 1.5, yet the position looked drawish with so little material on the board.


Stockfish won a pawn after exchanging a pair of rooks. Komodo took advantage of the pawn pajority on the queen side, it gave a pawn and created a passer, then pushed it to the 2nd row. The evals started to climb, this may have been a judgment error by Komodo. 


Stockfish blocked the passer with its knight, then traded its a pawn with the black h pawn. This created a pair of connected passers on the king side, and Komodo had to defend against this threat.


Both engines agreed black was losing. Stockfish's king had time to capture the black passer before the game was adjudicated.

In game 54 Komodo attacked through the center with a bishop and knight sacrifice that made the black king move forward. As a result Komodo captured a knight and created a central passer on the 7th rank. In a series of exchanges Stockfish gave back a bishop for the passer, so the total result of Komodo's attack was it being a pawn up in a quiet position. The engines removed all the pawns on the queen side, the game reached a QBN vs QBB position and the engines started to shuffle. The game continued more than 80 moves and ended in a drawn opposite color bishop position. Stockfish extends its lead to 4 points.

Games 55-56 started with black up a knight for pawns and the black king on f7. In game 55 both engines had a passer in the center. Komodo had an eval advantage for a while, a series of exchanges resulted in a BN vs R imbalance and evals dropped to 0. The engines exchanged most pieces, Stockfish gave a rook for a knight to capture the black passer. The remaining pawns vs bishop ending was a draw.
 
In game 56 Komodo castled long and concentrated forces on the king side facing the black king. Stockfish started with an eval of 1 (negative) which increased to over 2 when it moved its pieces to the queen side. On move 18 the engines started a series of pawn and piece exchanges that cleared the board. Stockfish's advantage in eval and material did not change.



There was only one black pawn left, and Stockfish made sure it was safe. Komodo's bishop pair and rook were not strong enough, Stockfish surrounded its king and pawn with pieces to avoid checks. After a while Stockfish cleared a safe path for its pawn and pushed it forward. 


Komodo could not stop the pawn without losing a piece, the material advantage was enough for Stockfish to win.

Games 57-58 were a Benko Gambit, accepted variant. Both started with white two pawns up and an open queen side for black. In game 57 Stockfish had an eval advantage for a while, Komodo had active pieces on the queen side and white found it difficult to castle its king. After several exchanges Stockfish finally castled, Komodo got the material back by move 22 and evals started to come down. Komodo opened the king side and created a NN vs R imbalance. The white king was exposed and on the run. Stockfish had a passer on the queen side, after exchanging most pieces Komodo forced a draw with perpetual check. In game 58 Komodo castled quickly, the black pieces were concentrated in the center and material was equal on move 19. Komodo captured two pawns and created a pair of connected passers on the queen side, Stockfish countered with a king side attack. A series of exchanges removed all threats and the game reached a QR vs QR position with evals at 0. After exchanging queens the game ended in a drawn rook ending.