Season 14 premier division after RR1

Crosstable after RR1

Stockfish leads after an outstanding RR with +4 result, Houdini is second with +2. Leela and Komodo have drawn all their games, Komodo's score is +1 due to an opponent crashing.
The bottom of the table is very close, KomodoMCTS, Andscacs and Ethereal with -2 and Fire with -1 (with one win).
KomodoMCTS crashed once in this RR, hopefully this will not happen again. It hasn't crashed before this season, recall that it played in all the divisions.


A few interesting games

Stockfish - KomodoMCTS: Stockfish's eval started to increase when it created a pair of connected passers in the center early in the game. KomodoMCTS captured one of the passers and went a pawn up, by then Stockfish had a strong king side attack and eval close to 2. After several exchanges only QB vs QB were left, with Stockfish a pawn up. Both kings were exposed, Stockfish had two advanced passers, KomodoMCTS gave the bishop and countered with its queen. The game was adjudicated when KomodoMCTS realized it couldn't give checks indefinitely, and then could not avoid a pawn queening.


Houdini - Andscacs: Houdini surprised with its first move after book, retreating its bishop. Andscacs handled the novelty very badly, it moved a bishop 4 times in its first 9 moves while Houdini developed and evals jumped over 2. Houdini blocked the center and opened the black king side. Andscacs lost a knight and pawns, the game was over quickly.

Fire - Ethereal: All bishops were off early, all the pawns remained on the board with evals close to 0. The first pawn exchange was on move 32 as the engines opened a file on the queen side. Ethreal shuffled while Fire slowly infiltrated the queen side. Evals increased as Fire moved its king away and opened the king side. The engines gradually exchanged pieces until only RN vs RN were left. Fire was two pawns up with an advanced passer, Ethereal lost the knight to stop it and Fire won.

Stockfish - Fire: See featured game below.

Ethereal - Stockfish: Ethereal had an eval advantage from the start, but when Ethereal chose to create a R vs BB imbalance evals became negative. After exchanging queens the black bishops were stronger than the white rooks. Ethereal's king was trapped, Stockfish moved its king forward and after exchanging down to a R vs BN position the black king was in a mating net.

Stockfish - Andscacs: Stockfish took over the game after queens were off early. Stockfish pushed pawns on the queen side and had a significant space advantage, though material was equal. With only rooks and knights remaining Stockfish created an advanced passer in the center and placed a rook on the 7th rank. Andscacs gave a rook for a knight and pushed a passer to the 2nd rank, the RRN vs RNN ending was a win for Stockfish.

Houdini - Fire: Houdini was a pawn up in a QRR vs QRR position. Houdini used an open file on the king side to threaten the black king and slowly improve. Evals jumped after the white queen infiltrated the back rank, Houdini created a central passer and the game was over quickly.

Featured game: Stockfish - Fire
Premier division, round 4
Link to game on TCEC

Evals were close to 0 at the start with a small advantage for Stockfish, perhaps because of its bishop pair. Fire pushed pawns on the king side and had a space advantage. Stockfish's eval then jumped over 1.5 after it gave two pawns on the queen side.

Fire still thought it was fine though its king was exposed and Stockfish dominated the long diagonal with a bishop. Then Stockfish opened a file on the king side and doubled rooks. Fire countered by pushing a passer to the 2nd rank, Stockfish's eval was already winning.

Fire it realized it was in trouble when Stockfish's queen joined the rooks and threatened mate. Fire had no choice but to block and exchange pieces, eventually losing material to save its king. 

The RB vs R ending was a win for Stockfish after it blocked the passer with its bishop and pushed its f pawn forward.

Season 14 division 1 final results

Final crosstable


Ginkgo crashed 4 times in the division and was disqualified. This means that Ginkgo is automatically relegated, and removing its games changes the table somewhat but does not change the promotions and other relegation.

Leela won division 1 convincngly, and KomodoMCTS finished 2nd. These two engines started in the lower divisions this season and both reach the premier division which is the final destination. This means that we will have a NN GPU engine in the premier division for the first time, as well as two Komodo versions playing.

Fritz is relegated together with Ginkgo. Fritz did not win any games in the division. It's a shame that Ginkgo crashed out, it would have been close to 3rd place if it were more stable.

A few interesting games

KomodoMCTS - Fizbo: Fizbo gave a pawn and opened the center, but did not get a strong attack. When Fizbo moved a rook forward KomodoMCTS trapped it. A series of exchanges that included a queen sacrifice and pawn promotion by Fizbo resulted in a QN vs QB position, KomodoMCTS two pawns up. Fizbo got one pawn back but KomodoMCTS reduced to a winning N vs B ending.


Leela - Jonny: Evals increased quickly though material was equal. Leela pushed pawns on the king side, trapping a bishop and keeping the black king in the corner. After reducing to a NN vs BN position Leela captured a pawn. It took Jonny a long time to untangle its king and bishop, Leela exchanged down to a knight ending and captured a second pawn for the win.

Fizbo - Laser: For 35 moves the position was equal, then evals started to jump. Fizbo sacrificed a knight on the king side, then got it back on the queen side and was a pawn up. Only RBB vs RBN remained, Laser lost a knight and tried to eliminate the white pawns. However Fizbo kept one pawn, enough for a win in a BB vs B position.

Jonny - Chiron: Chiron gave a rook for a knight early in the game. Evals increased for a while, Jonny's eval peaked over 2, but then the engines started to shuffle and the evals did not change. The engines reduced to a QR vs QN position and evals climbed again, this time Jonny found a winning path in a queen ending with a pawn up.

Leela - Fizbo: The game reached a bishop ending (same color) on move 32. Leela outplayed Fizbo, despite being a pawn down Leela created two passers and forced the black bishop and king to block them. This left the white king free, enough to win the game.

Fizbo - Jonny: Evals started to increase after Fizbo opened the king side, exposing the black king to attack. Jonny's king was close to being mated, by the time it was safe Fizbo was a pawn up in a RN vs RB position. Fizbo then captured another pawn, and two connected passers secured the win.

Leela - Laser: There were several early exchanges, Leela had a pawn majority on the queen side with a protected knight on c6. After some shuffling the engines exchanged queens and evals resumed their increase. Leela reduced to a won rook ending with 3 pawns up.

Ginkgo - Fizbo: Ginkgo went two pawns up with connected passers on the queen side. The white king stayed in the center and the white king side rook was stuck, but Fizbo could not get an attack going. Fizbo gave another pawn to open the king side, then it gave a rook for a knight, still its counter was too weak. Ginkgo started to push its queen side pawns and the game was adjudicated. Too bad that Ginkgo already crashed 3 times, it is still playing but the games will not be counted in the final crosstable.

With one RR left Leela is leading the table, 1.5 points ahead of KomodoMCTS and 3 points ahead of Fizbo (after removing Ginkgo related points). If the Fritz - Leela game will be replayed the lead will probably increase. It is quite safe to say Leela will win this division and promote. The bottom of the table is also decided after the disappointing crashing out of Ginkgo. Fritz is 2.5 points below Jonny, its only win is a questionable Leela crash. The only open race is for 2nd place between KomodoMCTS and Fizbo.

Fizbo - KomodoMCTS: Fizbo gave a knight for two pawns, opened the king side and exposed the black king. Evals started to increase after Fizbo created a queen side passer, and then it captured two more pawns and created passers in the center. Fizbo sacrificed a rook to promote one of the pawns to a queen in a Q vs RN position, winning after the white king came forward to support. There were two white wins in this opening. With this result Fizbo is only 0.5 points behind.


Fritz - Chiron: The game reached a RB vs RB position on move 27, and seemed to be heading for a draw. 35 moves later Chiron found a way to capture a pawn. Fritz' position collapsed and Chiron won in a slow endgame. A double win for Chiron in this opening.

Laser - Fizbo:  Laser had a small eval advantage from the start, it started to increase after move 30. Laser made threats on the king side while Fizbo's pieces were far from its king, then Laser captured a pawn on the queen side. The king side attack was over with a series of exchanges that left a double rook ending with Laser 2 pawns up, enough for a win. Another opening with two white wins.

KomodoMCTS extends its lead to 1 point after drawing against Leela, 5 rounds to go.

Fizbo - Leela: Fizbo played the openng badly, giving a pawn without real compensation. Leela had a small eval advantage from the start that increased gradually. Leela pushed pawns on the king side and won a rook for a bishop. Fizbo could not hold back the king side attack, it lost more material and the game was adjudicated when it was a rook down. A double win for Leela in this opening.

Fizbo with two losses in a row, KomodoMCTS drew against Chiron and its lead is 1.5 points with 4 rounds to go. Both engines still have a game against Ginkgo which will not count, so really only 3 games left each. Fizbo's chances are very low.

Jonny - Ginkgo: The game reached a RRB vs RRN position on move 19. Ginkgo took over after opening the king side and driving the white king away with its rooks. Eventually Jonny lost a bishop and the game.

Fizbo only managed a draw against Fritz while KomodoMCTS played against Ginkgo. Fizbo is 1 point behind with two games to play, KomodoMCTS has 3 more games.

Chiron - Leela: See featured game below. This was Leela's first and only loss in the division.

Leela - Ginkgo: Leela gave two pawns and developed a king side attack while the black king remained in the center and the black queen was far away. Ginkgo had to walk its king to the queen side, Leela reduced to a double rook ending, it had a pawn advantage and an active king which were enough for a win.

KomodoMCTS - Laser: After a series of exchanges only QN vs RRN remained on move 21. Evals started to increase as KomodoMCTS used its queen side majority to create a passer. Eventually Laser had to lose a rook to stop the passer, losing the game.

Fizbo only drew against Chiron, KomodoMCTS is leading by 1.5 points. Since Fizbo has only one more game to play KomodoMCTS secures 2nd place and promotion to the premier division.

Jonny - Fritz: Jonny outplayed Fritz in a QRB vs QRB ending.

Laser - Leela: Laser gave a rook for a bishop and pawns, it held the position until move 34. Leela broke through the pawn wall and won a bishop. Laser was up 4 pawns in a QRB vs QB position, but after queens were exchanged Leela's rook picked up the white pawns for a win. A double win for Leela in this opening.

Ginkgo - Chiron: Chiron's queen moved forward and Ginkgo trapped it. Chiron managed to exchange queens, but was a pawn down in a RN vs RB ending with its pieces stuck on the king side. By the time Chiron activated its pieces Ginkgo captured a pawn on the queen side, the game was adjudicated with Ginkgo 3 pawns up.

Leela - Fritz: What a rollercoaster game! The engines started shuffling on move 28, and a few pawn moves extended the shuffle to move 136. At this point Leela opened the queen side with exchanges, and shuffling resumed. Leela started to get optimistic, after 40 moves it broke through the center and created a passer. Fritz gave a rook for a bishop to stop the passer and the game reached a R vs B ending on move 198. Leela's eval reached over 7 and started to crawl back down, it didn't see a way to improve. Leela allowed Fritz to push a passer to the 2nd rank, its bishop protecting two crucial pawns, it seemed Leela had lost its chance of winning. Evals came down close to 0, Leela sacrificed a pawn on move 280 to continue playing, and then evals started to increase again. This time Leela did find a way to capture the passer and get the win, the game was finally adjudicated on move 308.

KomodoMCTS - Jonny: Jonny went for a BB vs R imbalance with a passer on the 3rd rank. When Jonny exchanged queens KomodoMCTS' eval started to increase. Jonny's pieces were passive and KomodoMCTS had a strong bishop pair, KomodoMCTS captured two pawns and exchanged down to a winning BB vs R ending.


Featured game: Chiron - Leela
Division 1, round 25
Link to game on TCEC

Chiron had an eval advantage though it gave 2 pawns early in the game. As compensation it had very strong bishops and a rook on the 7th rank. Leela captured a third pawn, it had 3 passers on the queen side and its queen partially trapped in front.


Chiron captured a bishop and material was seemingly equal. Chiron's eval started to increase, Leela didn't see any danger and it pushed its queen side pawns forward. Chiron seemed to sacrifice a bishop, but it couldn't be taken beacuse of a mate threat. Then Leela saw what was coming and its eval jumped over 2, too late.


The bishop still could not be taken, the f7 pawn is pinned and cannot take the white queen. The black king was in immediate danger and the black queen was hanging. Leela was forced to exchange pieces and lose its queen, reaching a QRN vs RRN position. Chiron had to deal with the black passers on the queen side, Leela fought back by capturing the remaining white pawns. The game reached a QN vs RN ending.


Leela tried to build a fortress, but it couldn't stop the white queen from getting to the back rank. Chiron found a way to drive away the black king and the game was adjudicated.

Season 14 division 1 statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins

 
Final draw rate was 59.8%.


Game termination

The three most common game termination causes were:
34.8% - TCEC win rule
27.7% - TCEC draw rule
16.1% - SyzygyTB 
16.1% - 3-Fold repetition


Ginkgo crashed 4 times in the division and was disqualified, Fritz crashed once. One Leela game was stopped due to a network failure and was later replayed.

Moves per game


Median= 63.5
Average= 71.0

There were 16 games longer than 100 moves, the longest was 308 moves (Leela - Fritz, round 28, Leela won, longest win in TCEC history).

Time per game (hours)

 
Median= 2:06
Average= 2:03

Openings

There were 6-move book openings in this stage chosen by Cato. The first letter of the ECO codes was distributed as follows:


The 6-move book determined the opening in most cases, 82.1% of the game pairs repeated the same ECO code twice, 76.8% repeated the same opening variant. All of the game pairs repeated the ECO first letter twice.

Reverse pairs, wins


Reverse pairs, same moves 


Pairs of reverse games diverged very quickly, 41.1% diverged immediately out of book, 82.1% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 15 plys (Leela - Jonny, rounds 1 and 8, Two knights defense, two draws)    

Season 14 division 1 live blog, Saturday Dec 22nd

The remaining race in division 1 is the race for 2nd place between Fizbo and KomodoMCTS. FIzbo beat KomodoMCTS in their last direct confrontation in round 22, their head to head score is 2-2. Fizbo just lost to Leela, it is still 1 point behind in 3rd place. Today we follow the KomodoMCTS - Chiron game in round 24.

move 11: The game followed theory until move 9, KomodoMCTS' 10th move Bd3 was rare and SF thought it was bad and gave a slightly negative eval. KomodoMCTS moved the bishop again to e2 in the next move, Chiron's eval turned negative.

move 16: Evals remain close to 0, Chiron's bishop pair looks strong in the center and it may develop a king side attack in the future. Will KomodoMCTS try something on the queen side?

move 22: KomodoMCTS blocks the dark squares on the king side, but creates a weakness on light squares with g3. Chiron pushed pawns on the king side, and its negative eval increased a little. SF suggested to exchange bishops, KomodoMCTS made a move on the queen side, causing SF to agree that black is better.

move 30: Chiron's attack on the king side led to a series of exchanges. Evals are negative but close to 0. The reasonable outcome of the game is a draw, one of the engines will need to blunder badly to lose the game.

move 37: Chiron thought for 7 minutes and then exchanged bishops. Chiron lowered its eval, then it jumped again as Chiron created a passer on the king side. I doubt anything will come out of it.

move 43: more exchanges and evals are down again. Only QRN vs QRB remain, the game was headed for adjudication and Chiron's eval jumped again. It doesn't want the game to end?

move 50: Queens are off and evals are at 0. Perhaps now we will have a draw?

move 68: finally a draw in a rook ending.

KomodoMCTS has a 1.5 points lead with 4 games remaining.

Season 14 division 1 after RR2

Crosstable after RR2

Division 1 has been more competitive than previous divisions this season. Leela and KomodoMCTS continue their journey to the top, but after two RRs it is still not clear whether they can promote to the premier division. Both have not lost a game in the division so far, Leela has a promising 1 point lead at the top. Fizbo and KomodoMCTS are in joint second place with other engines not too far away.
At the bottom Fritz is well on its way to division 2, having lost 8/14 games. Jonny and Chiron are candidates for relegation, nothing is decided yet.
There has been one crash so far, Ginkgo crashed against Fizbo

A few interesting games

Chiron - Fritz: Fritz took two pawns, letting Chiron trap its bishop. After Chiron captured the bishop it attacked the black king, Fritz exchanged pieces until reaching a RN vs R endgame. Chiron had enough pawns for a win.

Ginkgo - Jonny: Jonny gave a knight for 3 pawns early in the game. Ginkgo's eval increased as Jonny tried to protect its king. The game was adjudicated in a QRB vs QR position, with PV showing that Ginkgo is about to capture the black queen for a rook.


Laser - Fritz: Laser attacked on the king side, trapping the black queen in the corner with a pawn on f6. Fritz started to lose material and it was a rook down when the game was adjudicated.

Leela - Chiron: See featured game below.

Chiron - Fizbo: Chiron started the game with an eval advantage, but evals became negative after a few moves. Fizbo concentrated all its pieces on the king side and it was difficult for Chiron to defend its king. After opening the king side and exchanging a few pieces Fizbo increased the pressure until Chiron gave a rook for a knight. In a RB vs RR position Fizbo captured white pawns until the game was adjudicated.

KomodoMCTS - Fritz: KomodoMCTS gave two pawns on the king side and evals started to jump. Both Fritz' king and queen were targets for attack, after a series of exchanges the game reached a Q vs RB position. A few moves later KomodoMCTS captured the bishop and the game was adjudicated. 

Leela - Laser: Leela pushed pawns on the king side right after book, this stopped Laser's king side development, and its king had no safe place to go to. Laser was a pawn up but effectively two pieces down as evals jumped higher. The engines exchanged down to a RRB vs RRB position, by the time Laser freed its pieces Leela had a dangerous passer on the queen side. Laser lost a rook for a bishop for the passer, the R vs B ending was a win for Leela.

Chiron - Ginkgo: Chiron was down a rook for a bishop early in the game, but its eval was over 1 and increasing. It had a protected pawn on e6, restricting Ginkgo's movements. Chiron was stronger on the queen side, it captured black pawns and created a passer. Ginkgo gave the material back to stop the passer, the game reduced to a knight ending with Chiron 2 pawns up, enough for a win.

Ginkgo - Fizbo: Ginkgo had an eval advantage until move 30, then it went a pawn up but evals became negative. Fizbo put a pawn on h3, restricting the white king in the corner. The engines exchanged pieces until only RB vs RN remained, Fizbo pinned the white bishop and then attacked the white pawns on the queen side. Ginkgo lost its bishop while capturing a passer, resulting in a won ending for Fizbo.

Fritz - Leela: Fritz was a pawn up, evals turned negative after Leela created a protected passer on e3. Fritz tried to attack the uncastled black king through the queen side, leaving the white king with less defenders. Leela pressed on the king side, first capturing a rook for a knight and then exposing the king using its pawns. The game was adjudicated in a RN vs RR position with two black pawns on the 3rd rank.

Ginkgo - Fritz: Ginkgo pushed pawns on the king side, exposing its king, while Fritz kept its king in the center uncastled. Evals started to increase after Ginkgo created a hole in the black pawn line on the king side, it gave a knight while pushing a pawn to h7. Ginkgo then gave a rook and queened the pawn, the game reached a QB vs RBB position. A second advanced passer gave Ginkgo the win. 

Chiron - Jonny: Evals started to increase after the tension in the center was resolved in a series of exchanges that left only QBB vs QR. The bishop pair was strong, Chiron slowly inproved its position until capturing a pawn and creating a passer on the queen side. Jonny could not counter against the white king nor stop the passer, when it reached the 7th rank the game was adjudicated.

KomodoMCTS - Chiron: The engines started to shuffle behind pawn lines on move 25. Evals started to increase after KomodoMCTS brought its rooks forward and reduced to a QRB vs QRN position. KomodoMCTS created a queen side passer and opened the center, the passer was strong enough to give KomodoMCTS the win though the PVs showed there was still a long way to go.

Laser - Jonny: Laser had an eval advantage from the start. Evals stayed under 1 as the engines exchanged pieces, reaching an opposite color bishop ending on move 34. Then Jonny blundered unexpectedly, it allowed Laser to capture pawns on the queen side and create a connected pair of passers. The white king came forward and secured the win for Laser.

Chiron - Leela: Leela went a pawn up early and evals turned slightly negative. Chiron attacked the king side, Leela defended easily while its eval increased. Chiron's pieces retreated and Leela opened a hole on the king side, exposing the white king to attack. The pressure on the white king gradually increased, Chiron gave a rook for a bishop to remove the immediate danger. Leela reduced to a winning B vs R ending. Leela won this opening from both sides.

Jonny - Fritz: Jonny had an eval advantage from the start, and a significant space advantage as the black pawns were mostly on the 7th rank with the major pieces behind them. Fritz was paralyzed and Jonny slowly advanced and captured pawns until the game was over.

Fritz - KomodoMCTS: Fritz pushed pawns on the king side after castling long, capturing a rook for a bishop as a result. KomodoMCTS' king found safety behind a white pawn and the attack was over. Evals turned negative, KomodoMCTS attacked the queen side and it had 3 connected passers on the king side. Fritz exchanged down to an opposite color bishop ending, but it was 4 pawns down and lost. KomodoMCTS won this opening from both sides.

Ginkgo - Chiron: The black queen ventured forward and evals started to rise. Ginkgo chased the black queen for a while, then captured a black pawn with evals over 1. The game reached a QB vs QB position, Ginkgo attacked the black king and captured more pawns. It was 4 pawns up when the game was adjudicated. Both games in this opening were won by white.

Leela - Fritz: Leela had an eval advantage from the start, and it increased quickly. Fritz walked with its king to the king side and trapped its rook. Leela pushed pawns and blockaded the king side, then captured a pawn on the queen side and created connected passers. The game was adjudicated with Leela 3 pawns up in a RB vs RB position. A second double win for Leela.

Featured game: Leela - Chiron
Division 1, round 4
Link to game on TCEC

Leela gave a pawn early in the game, Chiron's king remained uncastled and it was late developing its queen side. Leela gave a second pawn, then applied pressure on the king side with doubled rooks on the h file. Switching to the queen side it gave more material and sacrificed a bishop.

Despite being behind on material Leela's eval was over 1. Chiron had two pieces trapped on the king side, its king stranded in the center. Leela pushed two connected passers on the queen side, Chiron gave material to stop the attack, resulting in a QR vs RBN position.

Chiron had to defend its king with its pieces, Leela's queen moved quickly across the board and Chiron could not handle all the threats. Leela targeted the black pawns on the king side that were left without defense.

Chiron tried a few checks but it only delayed the inevitable loss.

Season 14 division 2 statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins


Final draw rate was 60.7%.


Game termination

The three most common game termination causes were:
29.5% - SyzygyTB
27.7% - TCEC win rule

22.3% - TCEC draw rule

ChessBrain crashed once in the division. One Leela game stopped due to a network failure and was later adjudicated manually.

Moves per game


Median= 63.5
Average= 76.9

There were 22 games longer than 100 moves, the longest was 216 moves (Booot - Leela, round 25, draw).

Time per game (hours)


Median= 1:13
Average= 1:15

Openings

There were 6-move book openings in this stage chosen by Cato. The first letter of the ECO codes was distributed as follows:


The 6-move book determined the opening in most cases, 83.9% of the game pairs repeated the same ECO code twice, 78.6% repeated the same opening variant. In 1.8% of the game pairs (one pair) the ECO first letter was not repeated twice.

Reverse pairs, wins


Reverse pairs, same moves 


Pairs of reverse games diverged very quickly, 39.2% diverged immediately out of book, 80.3% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 11 plys (Gull - Xiphos, rounds 16 and 23, Sici lian Anderssen variation, Xiphos won as white, the other game was a draw) 

Season 14 division 2, final results

Final crosstable:



Leela and KomodoMCTS continue to move up, promoting to division 1. Gull and Texel are relegated to division 3.


With 3 rounds to go Leela was leading and sure of first place. The race for 2nd place was between KomodoMCTS and Xiphos, both with 14.5 points. Texel was last and could not avoid relegation. The race for 7th place was between Booot 12.5, Nirvana 11.5, ChessBrain 10.5 and Gull 10.5. ChessBrain had one crash which gave it a tiebreak disadvantage.

Nirvana - Booot: Evals stayed low as the engines exchanged pieces until adjudication.

Leela - Xiphos: The game reached a same colored bishop ending on move 32. Leela's eval jumped to 1.5 but Xiphos defended well, the game ended in a tablebase draw on move 143.

KomodoMCTS - ChessBrain: ChessBrain had a small eval advantage in the middle game, the game reduced to a rook ending which KomodoMCTS drew easily.

Texel - Gull: Gull had a real chance to win this game. It created a queen side passer and Texel gave a knight to remove it. The game reached a B vs BB position with negative evals over 2, but Gull couldn't find a way to convert. The game ended in a tablebase draw after 65 more moves.

After 4 draws there is no change in the table. Booot is almost surely safe from relegation.

Texel - Nirvana: Evals were low, the engines reduced to a rook ending and a draw.

Gull - KomodoMCTS: Evals were close to 0, Gull gave a rook for a knight and created a connected pair of passers on the queen side in a BN vs RB position. Then evals turned negative, KomodoMCTS' eval increased rapidly as it created a king side passer. Gull lost a knight for the black passer and KomodoMCTS won the endgame.

ChessBrain - Leela: The game quickly reduced to a drawn rook ending.

Xiphos - Booot: The engines exchanged all pieces and reached a drawn king and pawns endgame.

One round to go. KomodoMCTS leads Xiphos by 0.5 points. Booot and Nirvana are safe from relegation, ChessBrain is 0.5 points ahead of Gull in 7th place.

Nirvana - Xiphos: Evals were low in a mostly closed position. The engines exchanged pieces until only RB vs RB were left and the game was adjudicated. With this draw Xiphos ties with KomodoMCTS, its only hope is that KomodoMCTS loses its game against Texel, not likely.

Booot - ChessBrain: The game reached a double rook ending on move 25 and immediately ended in a repetition draw. ChessBrain leads Gull by a point, Gull needs a win against Leela to avoid relegation, also not likely.

Leela - Gull: The game reached an opposite color bishop ending on move 31, Leela wouldn't lower its eval for draw adjudication until move 165. Gull finishes 7th and is relegated to division 3.

KomodoMCTS - Texel: Evals increased from the start. The game reached a RB vs RB position, KomodoMCTS went a pawn up and created a passer in the center. Texel's pieces were paralyzed and KomodoMCTS won the game, though it shuffled for a while and it was not clear what the winning sequence was. KomodoMCTS finishes in 2nd place.

Season 14 division 2 live blog, Wednesday Dec 12th

In this post I'm not following a game. I was away for 2 days and missed all of RR3 of division 2. I'm having a quick look at the archive to see what I missed.

1. First thing that stands out is that Leela lost, Huh? Is this legit? The previous loss was a network failure and the game was manually adjudicated as a win for Leela. What happened here? Round 18 against Booot, the eval graph shows a blunder around move 85. Leela was up a pawn, the engines shuffled for a long time and then Booot pushed a pawn on the queen side and evals started jumping in black's favor. Did Leela blunder? What did SF (bluefish) have to say? The game reduced to a BN vs RB position which Booot won. Looks like a real loss to Leela. I bet the fans went crazy.

2. Leela is sure to promote to division 1, even if still not mathematically certain. After 20 round it had a 5 point lead over 3rd place, 3.5 points to 2nd place.

3. Komodo and Xiphos had a miserable RR, both with 3/6 points. The race for 2nd place is still open.

4. At the bottom of the table Texel is on its way to finish last, but hey - it won a game? Round 18 against ChessBrain? Again round 18 - a cosmic ray hit the server perhaps. The game reduced to a R vs B ending, Texel used its tablebase knowledge to convert the win.

5. At the bottom the race against 7th is very close. Gull (2.5/6) and Chessbrain (1.5/6) had a weak RR. Nirvana (3.5/6) and Booot (4/6) had better results. One point separates these 4 engines with 8 games to go.

Season 14 division 2 live blog, Monday Dec 10th

Division 2 is being played, the engines are stronger and the competition is harder. After 10 rounds it seems that Leela is going to win this division, but the second engine to promote could be any of KomodoMCTS, ChessBrain or Xiphos. The other 4 engines (Gull, Nirvana, Booot and Texel) are all in danger of relegation.

We follow the round 11 game Xiphos - KomodoMCTS, the reverse game was a draw. The book sequence is a QGD semi Slav defense, a popular opening line.

move 10: KomodoMCTS diverges from the reverse game in its first move out of book, choosing a less popular line. Its second move takes the game to a very rare line in human games.

move 15: Xiphos castled long, opposite direction castling may result in a fighting game, evals are low so far. KomodoMCTS opened the center, no pawn pushes so far by both engines.

move 24: Xiphos' eval increased a little, but it doesn't seem to have a plan so far. The engines exchanged all bishops and opened the position. There are many open files and the rooks are in danger of being exchanged soon.

move 31: Xiphos gave a pawn for some initiative on the king side. One pair of rooks was exchanged and only QRN vs QRN remain. I think the game is heading for a draw.

move 40: Now the queens are off, Xiphos is still a pawn down yet its eval is still around 0.4. The engines cleared more pawns and Xiphos is a pawn up, with two pawns on the queen side while KomodoMCTS has one pawn on the king side. KomodoMCTS captures one of the white pawns, Xiphos' eval jumps to around 1, I think it is delusional.

move 47: Xiphos' eval jumps over 2, KomodoMCTS reduces to a tablebase draw.

This result keeps the tension at the top of the table, the race for 2nd place is very close.

Season 14 division 3 statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins


Final draw rate was 45.5%. The draw rate was higher than in division 4 but still quite low.


Game termination

The three most common game termination causes were:
37.5% - TCEC win rule
22.3% - SyzygyTB
18.8% - TCEC draw rule

Hannibal crashed 5 times in the division, Arasan and rofChade crashed once each.

Moves per game


Median= 62.8
Average= 68.9

There were 13 games longer than 100 moves, the longest was 199 moves (Leela - Pedone, round 11, Leela won).

Time per game (hours)


Median= 1:15
Average= 1:14

Openings

There were 2-move book openings in this stage chosen by Cato. The first letter of the ECO codes was distributed as follows:


I'm dropping the opening 'family name' section. I noticed that the current opening naming used by TCEC is not consistent (e.g. "Sicillian", "Sicillian defense" both used, the separator can be ":" or ","). This has probably been true for several past reports.

The engines had a lot of freedom to choose the opening variant. Yet 57.1% of the game pairs repeated the same ECO code twice, and 50% repeated the same opening variant. In 7.1% of the game pairs the ECO first letter was not repeated twice.

Reverse pairs, wins


Reverse pairs, same moves 


Pairs of reverse games diverged very quickly, 50% diverged immediately out of book, 83.9% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 8 plys (rofChade - Hannibal, rounds 6 and 13, KGD Keene's defense, Hannibal crashed as white, otherwise two draws)

Season 14 division 3, final results

Final crosstable:
 


Hannibal was disqualied due to crashes. The table is not accurate since all Hannibal's games were ignored. However, the promotions and relegations do not change. Leela and KomodoMCTS were far better than the other engines in this division. The bottom of the table was more crowded, in the end Nemorino was relegated back to division4.

The bottom of the table with 3 rounds left was:

rofChade 9.5, 2 games left
Arasan 9, 3 games left
Pedone 9, 2 games left
Vajolet 8.5, 3 games left
Nemorino 8, 2 games left

At this stage Nemorino was most likely to be relegated. Vajolet was still in danger despite having more games to play, it still had to play both table leaders.

Pedone - rofChade: Pedone pushed pawns on the king side, exposing its king while attacking rofChade's king. Pedone exchanged Q for RN, opened the king side and created an advanced passer. rofChade lost its queen for a rook to stop the passer, leaving Pedone a knight and pawn up in a winning RBN vs RB ending.

KomodoMCTS - Arasan: Arasan survived a long game. After 50 moves Arasan gave a rook for a knight and pawn, KomodoMCTS' eval jumped to around 1. Arasan exchanged down to a R vs N endgame, it used a passer on the 2nd rank to hold the draw.

Vajolet - Leela: Vajolet was up a pawn with a queen side passer, it held the position until move 48. Leela pushed pawns on the king side and (negative) evals jumped over 2. The game reached a RB vs RR ending with a black pawn on the 2nd rank, Leela converted the win.

Two rounds to go. Vajolet is still 0.5 points ahead of Nemorino, both engines with two games left to play. The other engines increased their gap to at least 1.5 points, almost surely safe.

Vajolet - Pedone: Vajolet was up a pawn early in the game, Pedone did not find compensation and evals slowly increased. Vajolet created a queen side passer and exchanged down to a RB vs RN position. Pedone lost a knight for the passer and Vajolet won.

Arasan - Nemorino: The position was more or less static from move 27, on move 53 only the major pieces remained on the board and the engines shuffled until draw adjudication.

Last round: Pedone and Arasan are safe, Vajolet and rofChade are 1 point ahead of Nemorino. Nemorino's last game is white against Leela, and it needs a win, highly unlikely.

rofChade - Arasan: The game reached a double rook ending on move 29. Both engines pushed passers, the game ended in a perpetual check. rofChade is safe.

Nemorino - Leela: Leela gave two pawns and attacked the uncastled white king. Nemorino exchanged pieces, the game reached a rook ending. Leela regained the pawns, the black pawns were much better with a connected pair of passers on the king side. Leela won the game easily. After this loss Nemorino is relegated, Vajolet is safe.

Season 14 division 3 live blog, Thursday Dec 6th

Division 3 is being played, 3RRs done and one to go. The qualifiers for division 2 will be KomodoMCTS and Leela, they have a huge lead over the other engines in the division. They are figthing for first place with Leela ahead by 0.5 points, Leela is also leading 1-0 in the head-to-head score. The bottom of the table is less clear. Hannibal is last, disqualified due to crashes though it is still playing. Nemorino is in 7th place, 0.5 points below Vajolet  and 1.5 points below Arasan.

Currently Pedone is playing against KomodoMCTS at the start of round 22. The reverse game was a draw.

move 10: Pedone chose a less popular sideline in the Sicilian opening, still played at the top GM level. Pedone castled long, KomodoMCTS hasn't castled yet. The black queen side does not look safe for castling, KomodoMCTS may castle short and white can attack with its pawns.

move 15: KomodoMCTS castled short and Pedone is pushing its king side pawns. Evals are close to 0, Pedone is not attacking hard, it seems it doesn't have a clear plan.

move 21: Pedone exchanged pawns in the center, opening the position. It is a pawn up and has a bishop pair but evals remain close to 0. The rooks could be exchanged soon, will this be a quick draw?

move 25: Pedone seems to be preparing to push its g pawn. Meanwhile KomodoMCTS pushed a pawn on the queen side, Pedone's evals turned slightly negative after a long think.

move 30: Pedone continues to be slow on the king side and negative evals are increasing. After exchaging a pair of rooks KomodoMCTS' eval was over 1, the white pieces are on the king side and the white king does not look safe.

move 35: KomodoMCTS is threatening mate on the queen side, its eval jumping. Pedone was too slow and now it seems too late. Most of the white pieces are too far to help the king, now it seems black will win soon.

move 40: Now Pedone pushes the g pawn in desperation. KomodoMCTS ignores this and continues with its queen side attack. It captures a pawn, its eval over 5.

move 48: Pedone loses its queen for a bishop and a knight, game over.

Season 14 division 4 statistics

A summary statistics table of previous stages and seasons. 

Draw rate, wins

 
Final draw rate was 34.1%. The low draw rate reflects the wide range of engine strengths in this division. In particular ScorpioNN lost 43/44 games and KomodoMCTS won 32/44 games (and lost 1).


Game termination

The three most common game termination causes were:
43.9% - TCEC win rule
17.8% - SyzygyTB
12.9% - TCEC draw rule

ScorpioNN crashed 8 times in the division. It was allowed to continue playing since it lost all its games anyway, it had no effect on the table. Also of note are the 23 games that ended with mate on the board, with ScorpioNN the loser in almost all.

Moves per game


Median= 58.5
Average= 65.1

There were 27 games longer than 100 moves, the longest was 183 moves (Rodent - Tucano, round 37, draw).

Time per game (hours)
  
Median= 1:12
Average= 1:12

Openings

There were 2-move book openings in this stage chosen by Cato. 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:
Sicillian - 26 times
QGD - 14 times
French - 13 times

The engines had a lot of freedom to choose the opening variant. Yet 56.8% of the game pairs repeated the same ECO code twice, and 50.8% repeated the same opening variant. In 10.6% of the game pairs the ECO first letter was not repeated twice.

Reverse pairs, wins


Reverse pairs, same moves 


Pairs of reverse games diverged very quickly, 43.9% diverged immediately out of book, 79.5% of the pairs diverged at most after 1 move. The longest repeated sequence of moves was 10 plys (ScorpioNN - pirarucu, rounds 2 and 13, KGD Keene's defense, pirarucu won both games)