== UPDATE 8th October 2017 ==
Another delay in the season start. In a post on chessdom the new date is "next week", on the Facebook page it is "around Friday" (the 13th...) and I've seen the 15th mentioned on the chat. The cause for the delay is some "big drama" (Facebook quote again) behind the scenes with the server, but as a result the season will start with a new improved server with 44 cores. This is good news for season 10, I don't mind the delays too much, just get everything ready and let the games begin.
You can also watch Cato - aka Nelson Hernandez - explain the opening selection procedure for season 10.
== UPDATE 3rd October 2017 ==
The latest news is that the season will start on October 10th, see announcement on chessdom.
== Original post 25th September 2017 ==
TCEC season 10 has been announced on chessdom and is due to start in October, about 1-2 weeks from now. The TCEC chat volume is slowly increasing, with the usual participants starting to show up, as well as engine developers and of course Cato. The excitement is definitely building up.
There will be 24 engines in this season's competition, including three new to TCEC: Booot, Nemorino, and Wasp. The obvious favorites continue to be Stockfish, Houdini and Komodo, which will try to show that their new and updated versions are better than last season's as well as their rivals. Other engines that did well last season are Fire, Gull, Andscacs, Jonny and Ginkgo, it will be interesting to see how well they perform this season.
Season 10 will be shorter than season 9, with only three stages. The first stage will be a single RR of all engines, with 8 qualifiers. The time control for this stage will be 60 min + 10 sec/move, faster than previous seasons. The second stage will be two double RRs (each engine pair plays 4 games), 90 min + 10 sec/move, longer but still faster than usual in TCEC. The two best engines of the second stage will compete in the superfinal, the exact format not announced yet but probably 100 games.
The shorter time controls will be a challenge for me, it's hard to follow so many games every day and to find the time to write about the more interesting ones. I will do my best to keep up. I plan to post updates about the games as well as statistics reports for each stage, similar to my posts during the last two seasons.
Let's hope we have a successful and exciting TCEC season, with many interesting games, a little controversy, a reasonable draw rate, and very few technical problems.
Go TCEC!!
Monday, September 25, 2017
Friday, September 8, 2017
Season 6 superfinal, games 53-58
This is part 10 of my looking back at the Komodo-Stockfish superfinal match of season 6. Previous parts can be found at
part 1, games 1-8
part 2, games 9-16
part 3, games 17-24
part 4, games 25-28
part 5, games 29-32
part 6, games 33-36
part 7, games 37-40
part 8, games 41-48
part 9, games 49-52
After 52 games Stockfish led 12-4 with 36 draws.
In game 53 there were many exchanges after the opening with only RRB vs RRB remaining on move 18. Stockfish had a small eval advantage and better placed pieces, and a potential pawn advantage on the queen side.
Komodo's rooks remained passive and its king could not leave the king side, while Stockfish's king moved up the queen side. After exchanging bishops Stockfish's eval advantage was over 2.
Stockfish captured the black c pawn and Komodo's defense crumbled. After exchanging a few pawns and a pair of rooks Stockfish had two advanced passers on the queen side which were decisive.
The reverse game 54 started in a similar sequence of moves, again with only RRB vs RRB left on move 19. Komodo had a small eval advantage and an advanced passer, but since the bishops were of opposite colors the position was more drawish.
There were a few pawn exchanges which simplified the position. Komodo held to its strong passer and doubled rooks on the e file, Stockfish tried to defend with only a little room to move. The evals climbed above 1 for white, Stockfish's eval significantly higher.
There were several shuffling moves and it seemed that Komodo could not find a way to break through the black defense. Stockfish then advanced its g pawn, and in the new position Komodo found a path to victory. Stockfish sacrificed a pawn on the king side to gain a passer on the g file, but with Komodo controlling g1 with its bishop and with a pawn advancing on the f file the game was soon over. What would have happened if Stockfish continued shuffling? My guess - a draw. Stockfish prepared for a threat Komodo did not see.
Game 55 started with many exchanges that left RBN vs RRN after move 21, Stockfish an exchange down but with two more pawns. The evals were a little in white's favor but after exchanging a pair of rooks the evals dropped to zero. The pawns advanced as far as they could and the position became static, ending the game in a repetition draw.
The reverse game started similarly, reaching a RBN vs RRB position after move 21 and Komodo with an extra pawn. The evals were close to zero when Komodo chose to give back the exchange, it had an advanced passer and a centered king in a RB vs RB ending. Stockfish had no problem holding its position, it took another 20 moves but the game ended in a draw.
Game 57 was a 22 move miniature that ended in a repetition draw, while Stockfish was two pawns down. It is interesting to note that Stockfish saw the outcome in its PV starting from move 10.
In game 58 Komodo avoided an early queen exchange, Stockfish had a pawn advantage in a closed position. After a few exchanges the position opened with QRB vs QRB remaining, and the evals dropped to zero. Komodo gave a pawn and ended the game with a perpetual check.
After 58 games Stockfish leads by 13-5 with 40 draws. There are only 6 games remaining so Stockfish will win the match, regardless of the results of the last games.
part 1, games 1-8
part 2, games 9-16
part 3, games 17-24
part 4, games 25-28
part 5, games 29-32
part 6, games 33-36
part 7, games 37-40
part 8, games 41-48
part 9, games 49-52
After 52 games Stockfish led 12-4 with 36 draws.
In game 53 there were many exchanges after the opening with only RRB vs RRB remaining on move 18. Stockfish had a small eval advantage and better placed pieces, and a potential pawn advantage on the queen side.
Komodo's rooks remained passive and its king could not leave the king side, while Stockfish's king moved up the queen side. After exchanging bishops Stockfish's eval advantage was over 2.
Stockfish captured the black c pawn and Komodo's defense crumbled. After exchanging a few pawns and a pair of rooks Stockfish had two advanced passers on the queen side which were decisive.
The reverse game 54 started in a similar sequence of moves, again with only RRB vs RRB left on move 19. Komodo had a small eval advantage and an advanced passer, but since the bishops were of opposite colors the position was more drawish.
There were a few pawn exchanges which simplified the position. Komodo held to its strong passer and doubled rooks on the e file, Stockfish tried to defend with only a little room to move. The evals climbed above 1 for white, Stockfish's eval significantly higher.
There were several shuffling moves and it seemed that Komodo could not find a way to break through the black defense. Stockfish then advanced its g pawn, and in the new position Komodo found a path to victory. Stockfish sacrificed a pawn on the king side to gain a passer on the g file, but with Komodo controlling g1 with its bishop and with a pawn advancing on the f file the game was soon over. What would have happened if Stockfish continued shuffling? My guess - a draw. Stockfish prepared for a threat Komodo did not see.
Game 55 started with many exchanges that left RBN vs RRN after move 21, Stockfish an exchange down but with two more pawns. The evals were a little in white's favor but after exchanging a pair of rooks the evals dropped to zero. The pawns advanced as far as they could and the position became static, ending the game in a repetition draw.
The reverse game started similarly, reaching a RBN vs RRB position after move 21 and Komodo with an extra pawn. The evals were close to zero when Komodo chose to give back the exchange, it had an advanced passer and a centered king in a RB vs RB ending. Stockfish had no problem holding its position, it took another 20 moves but the game ended in a draw.
Game 57 was a 22 move miniature that ended in a repetition draw, while Stockfish was two pawns down. It is interesting to note that Stockfish saw the outcome in its PV starting from move 10.
In game 58 Komodo avoided an early queen exchange, Stockfish had a pawn advantage in a closed position. After a few exchanges the position opened with QRB vs QRB remaining, and the evals dropped to zero. Komodo gave a pawn and ended the game with a perpetual check.
After 58 games Stockfish leads by 13-5 with 40 draws. There are only 6 games remaining so Stockfish will win the match, regardless of the results of the last games.
Monday, August 28, 2017
Season 6 superfinal, games 49-52
This is part 9 of my looking back at the Komodo-Stockfish superfinal match of season 6. Previous parts can be found at
part 1, games 1-8
part 2, games 9-16
part 3, games 17-24
part 4, games 25-28
part 5, games 29-32
part 6, games 33-36
part 7, games 37-40
part 8, games 41-48
After 48 games Stockfish led 11-3 with 34 draws.
In game 49 Stockfish had advanced passers on the queen side while the evals stayed close to 0. Stockfish was able to march one pawn to the 7th rank where Komodo blocked it. After queens were exchanged Komodo countered with pawns on the king side, both engines ran out of ideas and agreed to a draw.
The reverse game was much sharper. Stockfish sacrificed a knight for pawns, then broke through the center and threatened to win material with a QR skewer by a bishop. Komodo chose to give its queen leading to a RBB vs Q and pawns imbalance. Stockfish's eval was at 0 while Komodo thought it had a small advantage. It took a few exchanges and 30 more moves for Komodo to see that it could not penetrate Stockfish's defense.
Game 51 started with a small eval advantage for Stockfish. Both engines played moves that were expected in their opponent's PV and evals stayed low until Stockfish's pawns advanced on the king side.
Stockfish's king was exposed but Komodo was under too much pressure to do anything about that. With a bishop and knight trapped on the king side Komodo could only wait while Stockfish arranged its pieces for an attack. With the black queen on the opposite side of the board Stockfish opened up the king side.
The evals shot up as Komodo could not defend its king without losing material, especially after f7 was played. Stockfish won a few moves after that.
The reverse game 52 repeated the opening moves and the evals stayed low. Komodo chose to keep its king side pawns close to the king and Stockfish's king looked secure. Then Komodo managed to trap a knight and Stockfish took two pawns for it, leading to the following position:
Komodo had an extra knight while its king had no shelter. On the other hand Stockfish's pieces could hardly move (except the queen). Stockfish spent several moves to free its bishop while Komodo advanced its knight to a strong forward position. Komodo's eval gradually increased, while Stockfish's eval increased much faster, almost 2.5 as the bishops were exchanged. Then for a moment it seemed that Komodo blundered the win, Stockfish's eval dropped below 1 and it anticipated a drawn ending. Komodo had other plans as it threatened a mate in 1.
Stockfish was completely surprised, it immediately saw that the game was lost with evals shooting above 4. The game was over a few moves later. A rare Komodo win, and very uncharacteristic behavior for Stockfish's eval function.
After 52 games Stockfish leads 12-4 with 36 draws.
part 1, games 1-8
part 2, games 9-16
part 3, games 17-24
part 4, games 25-28
part 5, games 29-32
part 6, games 33-36
part 7, games 37-40
part 8, games 41-48
After 48 games Stockfish led 11-3 with 34 draws.
In game 49 Stockfish had advanced passers on the queen side while the evals stayed close to 0. Stockfish was able to march one pawn to the 7th rank where Komodo blocked it. After queens were exchanged Komodo countered with pawns on the king side, both engines ran out of ideas and agreed to a draw.
The reverse game was much sharper. Stockfish sacrificed a knight for pawns, then broke through the center and threatened to win material with a QR skewer by a bishop. Komodo chose to give its queen leading to a RBB vs Q and pawns imbalance. Stockfish's eval was at 0 while Komodo thought it had a small advantage. It took a few exchanges and 30 more moves for Komodo to see that it could not penetrate Stockfish's defense.
Game 51 started with a small eval advantage for Stockfish. Both engines played moves that were expected in their opponent's PV and evals stayed low until Stockfish's pawns advanced on the king side.
Stockfish's king was exposed but Komodo was under too much pressure to do anything about that. With a bishop and knight trapped on the king side Komodo could only wait while Stockfish arranged its pieces for an attack. With the black queen on the opposite side of the board Stockfish opened up the king side.
The evals shot up as Komodo could not defend its king without losing material, especially after f7 was played. Stockfish won a few moves after that.
The reverse game 52 repeated the opening moves and the evals stayed low. Komodo chose to keep its king side pawns close to the king and Stockfish's king looked secure. Then Komodo managed to trap a knight and Stockfish took two pawns for it, leading to the following position:
Komodo had an extra knight while its king had no shelter. On the other hand Stockfish's pieces could hardly move (except the queen). Stockfish spent several moves to free its bishop while Komodo advanced its knight to a strong forward position. Komodo's eval gradually increased, while Stockfish's eval increased much faster, almost 2.5 as the bishops were exchanged. Then for a moment it seemed that Komodo blundered the win, Stockfish's eval dropped below 1 and it anticipated a drawn ending. Komodo had other plans as it threatened a mate in 1.
Stockfish was completely surprised, it immediately saw that the game was lost with evals shooting above 4. The game was over a few moves later. A rare Komodo win, and very uncharacteristic behavior for Stockfish's eval function.
After 52 games Stockfish leads 12-4 with 36 draws.
Saturday, December 10, 2016
Season 9 is over !!
I'm finally done with my TCEC backlog, I was trailing the superfinal by as many as 20 games which can be frustrating. TCEC stops for no man (unless the server crashes) and we have to keep up. Now I have time for a few remarks to close the season.
This season was so long I forget how it was in the early rounds. Stockfish was dominant the whole season, as it was in season 6 when it won a TCEC superfinal for the first time. This season's superfinal seemed to be decided quite quickly. Houdini was able to win several games but Stockfish gained points much faster. For me stage 3 was more interesting to watch because of the close race for second place between Houdini and Komodo. I believe that Komodo would have been a tougher opponent for Stockfish in the superfinal, but we'll never know.
Houdini made a comeback this season. For several years it was not updated and Stockfish and Komodo were consistently better. It was even close to dropping below third place. This season in stage 3 Houdini got a new version which was much stronger, and it beat Komodo in stage 3 to reach the superfinal. There is now a new commercial version of Houdini which is available. It needs to be continually developed if it wants to stay at the top level of computer chess.
There were two controversial games this season. The first was in stage 3, where in the first game Komodo lost to the new Houdini version, but the the game was replayed since Komodo played with the wrong parameters. The second was game 17 of the superfinal where both engines thought the game was a draw but the tablebase decision was a win for Stockfish. The win disregards the 50 move draw rule, which explains why the engines ignored it. There was never an official decision about this game.
The tournament director Anton was missing in the later parts of the season, sometimes causing confusion about procedure. In particular for a long time no one knew when the superfinal would start, even if there would be a superfinal at all. The rapid tournament that followed stage 3 was also a surprise, and in my mind it should not be a part of TCEC, and especially not between stage 3 and the superfinal. I hope that season 10 will be organized better.
I celebrated a few achievments for the blog:
- more than 100 posts
- readers from all over the world, all 6 continents represented
- more than 1000 hits in one month this November
- over 7000 all time hits
- google search 'tcec statistics' and 'tcec season 9' finds the blog
All this was achieved with the help of YOU, so thanks a lot. One thing that I would like that is missing so far is feedback. If you have a suggestion, an opinion or a question regarding a post you can add it as a comment. This could enrich the blog and make it more interesting.
I need a long break from TCEC, I hope to return for season 10 to enjoy more high level computer chess.
Bye for now.
This season was so long I forget how it was in the early rounds. Stockfish was dominant the whole season, as it was in season 6 when it won a TCEC superfinal for the first time. This season's superfinal seemed to be decided quite quickly. Houdini was able to win several games but Stockfish gained points much faster. For me stage 3 was more interesting to watch because of the close race for second place between Houdini and Komodo. I believe that Komodo would have been a tougher opponent for Stockfish in the superfinal, but we'll never know.
Houdini made a comeback this season. For several years it was not updated and Stockfish and Komodo were consistently better. It was even close to dropping below third place. This season in stage 3 Houdini got a new version which was much stronger, and it beat Komodo in stage 3 to reach the superfinal. There is now a new commercial version of Houdini which is available. It needs to be continually developed if it wants to stay at the top level of computer chess.
There were two controversial games this season. The first was in stage 3, where in the first game Komodo lost to the new Houdini version, but the the game was replayed since Komodo played with the wrong parameters. The second was game 17 of the superfinal where both engines thought the game was a draw but the tablebase decision was a win for Stockfish. The win disregards the 50 move draw rule, which explains why the engines ignored it. There was never an official decision about this game.
The tournament director Anton was missing in the later parts of the season, sometimes causing confusion about procedure. In particular for a long time no one knew when the superfinal would start, even if there would be a superfinal at all. The rapid tournament that followed stage 3 was also a surprise, and in my mind it should not be a part of TCEC, and especially not between stage 3 and the superfinal. I hope that season 10 will be organized better.
I celebrated a few achievments for the blog:
- more than 100 posts
- readers from all over the world, all 6 continents represented
- more than 1000 hits in one month this November
- over 7000 all time hits
- google search 'tcec statistics' and 'tcec season 9' finds the blog
All this was achieved with the help of YOU, so thanks a lot. One thing that I would like that is missing so far is feedback. If you have a suggestion, an opinion or a question regarding a post you can add it as a comment. This could enrich the blog and make it more interesting.
I need a long break from TCEC, I hope to return for season 10 to enjoy more high level computer chess.
Bye for now.
Friday, December 9, 2016
Season 9 superfinal, games 93-100
Stockfish is the winner of the season 9 superfinal !!!
We've known that would be the result for some time now, but now it is official.
After 100 games the result is 17-8 with 75 draws.
Stockfish started game 93 with an eval advantage that gradually increased. The pawn structure was a mess for both engines and both kings did not castle. Starting from move 17 the engines played out a sequence of 14 moves they both predicted, in which Stockfish sacrificed a knight and got it back, queens were exchanged, and Houdini's king side pawns were gone. At move 30 only RRB vs RRB remained.
Stockfish's connected passers were a long term threat that Houdini had to deal with. It used the rooks to make checks and attack the white pieces. Stockfish was patient and made a pawn move whenever it had a chance and only if it was safe. The pawns were half of the way across when Stockfish exchanged the bishops.
Houdini could only delay the inevitable with its rooks. Stockfish just had to be careful not to get mated and to avoid perpetual check. Once the pawns got close enough to queening the game would be over. With this win Stockfish goes up to +10.
In the reverse game Stockfish shut down Houdini's attack very quickly. The king side pawns remained intact and both kings castled. Evals fell to 0 as the engines continued to exchange pieces, reaching BN vs BN position on move 33. The game ended in a tablebase draw.
Game 95 started with an advantage for black, a rare occurence in the match. Houdini was a pawn up out of the opening, Stockfish gave a second pawn to get the initiative. After clearing the center there was a series of exchanges,. leading to material equality and a drawn rook ending.
Stockfish got nothing out of the opening in game 96, evals were close to 0. There was a pawn advantage for black on the queen side, but Houdini's position looked quite safe and the game seemed to be going nowhere. There was a long shuffle in which Stockfish's king walked to the queen side, preparing a break on the king side, while Houdini was getting very low on time. When the break came the evals increased to about 1 (for black), the king side opened and the game reached a double rook ending with Stockfish a pawn up. However Houdini managed to hold the position while playing on increments. It exchanged pawns and a pair of rooks to get to a rook ending with 2 vs 1 pawns on the queen side, a draw. This was probably the closest to a black win we would get in the match.
In game 97 Houdini gave a pawn and opened the center. After many exchanges the game reached a RBN vs RBB position, Stockfish a pawn up while Houdini had a passer on the queen side. To stop the passer Stockfish exchanged the minor pieces leading to a drawn rook ending.
In game 98 the position remained closed with very few exchanges. Evals remained close to 0 when the king side opened and both kings became exposed. Instead of attacking the engines settled for a repetition draw on move 35. Are the engines tired after a long match and want to go home?
Houdini's king stayed uncastled in game 99, Stockfish attacked the king side with its pawns after castling long. Stockfish sacrificed a pawn and tried to open up the king side, Houdini's defense remained strong and the result was a quick repetition draw on move 32.
In the final game 100 Stockfish castled into the pawn storm on the king side which looked dangerous. Houdini sacrificed a pawn and got a strong king side attack while trapping one of the black bishops, evals climbed above 1. Stockfish realized it was in trouble and it exchanged pieces giving a rook for a bishop and pawns to get to a RRB vs RBB position.
The black bishops were on the edge of the board and it took a few moves to put them in better positions. Meanwhile Houdini was capturing pawns, clearing the queen side and creating passers. Stockcfish tried to block the king side with its remaining pieces but it was hopeless.
The white pawns started to march and Stockfish did not have enough strength to stop all of them. It was able to trade one of its pawns for one of the passers but no more. When Houdini's remaining pawns reached the 6th rank Stockfish resigned. Houdini won the last game, but it was Stockfish that won the match.
We've known that would be the result for some time now, but now it is official.
After 100 games the result is 17-8 with 75 draws.
Stockfish started game 93 with an eval advantage that gradually increased. The pawn structure was a mess for both engines and both kings did not castle. Starting from move 17 the engines played out a sequence of 14 moves they both predicted, in which Stockfish sacrificed a knight and got it back, queens were exchanged, and Houdini's king side pawns were gone. At move 30 only RRB vs RRB remained.
Stockfish's connected passers were a long term threat that Houdini had to deal with. It used the rooks to make checks and attack the white pieces. Stockfish was patient and made a pawn move whenever it had a chance and only if it was safe. The pawns were half of the way across when Stockfish exchanged the bishops.
Houdini could only delay the inevitable with its rooks. Stockfish just had to be careful not to get mated and to avoid perpetual check. Once the pawns got close enough to queening the game would be over. With this win Stockfish goes up to +10.
In the reverse game Stockfish shut down Houdini's attack very quickly. The king side pawns remained intact and both kings castled. Evals fell to 0 as the engines continued to exchange pieces, reaching BN vs BN position on move 33. The game ended in a tablebase draw.
Game 95 started with an advantage for black, a rare occurence in the match. Houdini was a pawn up out of the opening, Stockfish gave a second pawn to get the initiative. After clearing the center there was a series of exchanges,. leading to material equality and a drawn rook ending.
Stockfish got nothing out of the opening in game 96, evals were close to 0. There was a pawn advantage for black on the queen side, but Houdini's position looked quite safe and the game seemed to be going nowhere. There was a long shuffle in which Stockfish's king walked to the queen side, preparing a break on the king side, while Houdini was getting very low on time. When the break came the evals increased to about 1 (for black), the king side opened and the game reached a double rook ending with Stockfish a pawn up. However Houdini managed to hold the position while playing on increments. It exchanged pawns and a pair of rooks to get to a rook ending with 2 vs 1 pawns on the queen side, a draw. This was probably the closest to a black win we would get in the match.
In game 97 Houdini gave a pawn and opened the center. After many exchanges the game reached a RBN vs RBB position, Stockfish a pawn up while Houdini had a passer on the queen side. To stop the passer Stockfish exchanged the minor pieces leading to a drawn rook ending.
In game 98 the position remained closed with very few exchanges. Evals remained close to 0 when the king side opened and both kings became exposed. Instead of attacking the engines settled for a repetition draw on move 35. Are the engines tired after a long match and want to go home?
Houdini's king stayed uncastled in game 99, Stockfish attacked the king side with its pawns after castling long. Stockfish sacrificed a pawn and tried to open up the king side, Houdini's defense remained strong and the result was a quick repetition draw on move 32.
In the final game 100 Stockfish castled into the pawn storm on the king side which looked dangerous. Houdini sacrificed a pawn and got a strong king side attack while trapping one of the black bishops, evals climbed above 1. Stockfish realized it was in trouble and it exchanged pieces giving a rook for a bishop and pawns to get to a RRB vs RBB position.
The black bishops were on the edge of the board and it took a few moves to put them in better positions. Meanwhile Houdini was capturing pawns, clearing the queen side and creating passers. Stockcfish tried to block the king side with its remaining pieces but it was hopeless.
The white pawns started to march and Stockfish did not have enough strength to stop all of them. It was able to trade one of its pawns for one of the passers but no more. When Houdini's remaining pawns reached the 6th rank Stockfish resigned. Houdini won the last game, but it was Stockfish that won the match.
Tuesday, December 6, 2016
Season 9, superfinal stats
Draw rate, wins
Final draw rate was 75%. In the superfinal last season it was 89%, many more decisive games this season, more fun to watch. There were no black wins, only a few of the openings (one?) had a black bias and all these games ended in draws.
Game termination
The three most common game termination causes were:
35% - TCEC draw rule
24% - TCEC win rule
24% - TB position
Moves per game
Median=58.5
Average=63.7
The games were a little shorter than in stage 3, draws were usually shorter than decisive games. Another example of the 'superfinal draw effect': high level + drawish games => short draws.
Time per game (hours)
Median= 5:45
Average= 5:39
Games were longer than in stage 3 by about an hour. This agrees with the addition of 30 minutes to each engine's clock. However it contradicts the 'superfinal draw effect'.
Openings
The first letter of the ECO codes of the superfinal openings was distributed as follows:
Openings were chosen by Jeroen Noonen, I assume with more human-oriented criteria than what Cato used in previous stages and seasons. As a result there were more open games (C) and Sicillians (B) and less flank openings (A).
If we use the opening 'family name' (using format FAMILY_NAME: VARIANT....) the top 3 are:
Sicillian - 14 times
French - 8 times
King's indian - 8 times
Spanish - 8 times
The number of predetermined moves varied depending on the opening, the opening lines were usually quite long. All the reverse pairs had the same ECO code, in 4 openings the full opening name was different.
Reverse pairs, wins
There were only 3 cases of an opening with two white wins, potentially a biased opening. This includes the notorious game 17. All in all excellent opening choices.
Reverse pairs, same moves
How many plys did the engines play after book until the first divergence in the reverse games?
Most games (62%) repeated at most 1 full move, only 16% repeated more than 2 moves. This is the usual outcome of the excellent opening choices in TCEC, very few forced lines or trivial continuations after the predetermined book moves. The longest repeat was 7.5 moves in games 29 and 30.
Final draw rate was 75%. In the superfinal last season it was 89%, many more decisive games this season, more fun to watch. There were no black wins, only a few of the openings (one?) had a black bias and all these games ended in draws.
Game termination
The three most common game termination causes were:
35% - TCEC draw rule
24% - TCEC win rule
24% - TB position
Moves per game
Median=58.5
Average=63.7
The games were a little shorter than in stage 3, draws were usually shorter than decisive games. Another example of the 'superfinal draw effect': high level + drawish games => short draws.
Time per game (hours)
Average= 5:39
Games were longer than in stage 3 by about an hour. This agrees with the addition of 30 minutes to each engine's clock. However it contradicts the 'superfinal draw effect'.
Openings
The first letter of the ECO codes of the superfinal openings was distributed as follows:
If we use the opening 'family name' (using format FAMILY_NAME: VARIANT....) the top 3 are:
Sicillian - 14 times
French - 8 times
King's indian - 8 times
Spanish - 8 times
The number of predetermined moves varied depending on the opening, the opening lines were usually quite long. All the reverse pairs had the same ECO code, in 4 openings the full opening name was different.
Reverse pairs, wins
There were only 3 cases of an opening with two white wins, potentially a biased opening. This includes the notorious game 17. All in all excellent opening choices.
Reverse pairs, same moves
How many plys did the engines play after book until the first divergence in the reverse games?
Monday, December 5, 2016
Season 9 superfinal, games 85-92
After 92 games Stockfish is leading 16-7 with 69 draws. With only 8 games left and a lead of +9 Stockfish is officially the winner of the match (if game 17 status is changed to a draw then Stockfish is still 0.5 points short).
Game 85 was a Benko Gambit, white started with a pawn up and a passer on the queen side. Stockfish had an small eval advantage after the opening and the action was focused on the open queen side. Houdini brought all its pieces there to block the white pawns. After a knight blocked the b-file and the queens were exchanged the evals started to fall to 0. After opening the king side Stockfish got the pawn back and created passers in the center. Eventually Houdini had to give up its passer to stop the black pawns, the engines continued to exchange until reaching a drawn rook ending.
In game 86 Houdini took a different approach. It gave up the pawns advantage and the passer to open up the queen side for its queen and rook. This led to many exchanges and a RN vs RN position on move 30. Houdini's eval advantage was gone a few moves later. Stockfish exchanged the rooks and the pawns were quickly captured, when the last white pawn was gone Houdini could not win with only a knight. Two Benkos, two draws.
Game 87 started with both kings in the center and with black's king side open. Stockfish captured two pawns in the center but its king was stuck and could not castle while Houdini's king castled long. Houdini attacked through the king side with a QN combination, leading to exchanges and a RRB vs RRB position. Stockfish was still a pawn up but Houdini's rooks were more active. After exchanging a pair of rooks the extra pawn was not enough in an opposite color bishops setting.
In game 88 both kings remained in the center and queens were exchanged early. Houdini was a pawn up and Stockfish attacked through the king side, leading to a series of exchanges and a rook ending by move 28. Evals fell quickly to 0 and the game ended in a draw after most of the pawns were gone.
Game 89 started with black a pawn up, the queen attacking and pieces in awkward positions. The evals stayed low throughout the game, both kings did not castle but were relatively safe once the queens were exchanged. Only RRB vs RRN remained after move 28, and after a few pawn exchanges Stockfish ended the game with perpetual check.
In a similar position in game 90 Houdini offered a bishop sacrifice to open up the king side but Stockfish declined. After a series of exchanges Houdini was a pawn up in a double rook ending on move 31. The engines eliminated the queen side pawns, then exchanged a pair of rooks. The remaining rook ending was a draw but it took about 50 moves for the engines to agree.
Game 91 started with a closed Spanish opening, most of the pieces remained on the board with pawns mostly locked. Stockfish had a small eval advantage, perhaps a small space advantage and two knights that are stronger in closed positions. Houdini's bishops were quite miserable.
Stockfish's eval gradually increased though it was not clear why at first. Houdini exchanged knights, leaving Stockfish with one while Houdini had none. There were many weak pawns, both black and white, in particular the black b4 and g4 pawns could not be defended. After exchanging queens the black king side pawn line was broken and evals were over 1.5.
Taking its time Stockfish captured the b and g pawns, exchanging a rook pair in the process with RBN vs RBB remaining. Stockfish then sacrificed two pawns and created 3 passers across the board.
Houdini also had two passers but the white pawns were a more immediate threat. Houdini could not defend against all three without losing material. Stockfish squeezed a win out of this closed position, it is at +9.
In game 92 the engines exchanged more pawns and the position was more open. After opening the queen side both engines had a passer there. The engines exchanged queens and Stockfish gave the queen side passer and gained one in the center. Stockfish's eval at this point fell to 0, Houdini kept a small eval for a while longer. The game reached a RN vs RB position, Houdini kept one last pawn but it was not enough for a win.
Game 85 was a Benko Gambit, white started with a pawn up and a passer on the queen side. Stockfish had an small eval advantage after the opening and the action was focused on the open queen side. Houdini brought all its pieces there to block the white pawns. After a knight blocked the b-file and the queens were exchanged the evals started to fall to 0. After opening the king side Stockfish got the pawn back and created passers in the center. Eventually Houdini had to give up its passer to stop the black pawns, the engines continued to exchange until reaching a drawn rook ending.
In game 86 Houdini took a different approach. It gave up the pawns advantage and the passer to open up the queen side for its queen and rook. This led to many exchanges and a RN vs RN position on move 30. Houdini's eval advantage was gone a few moves later. Stockfish exchanged the rooks and the pawns were quickly captured, when the last white pawn was gone Houdini could not win with only a knight. Two Benkos, two draws.
Game 87 started with both kings in the center and with black's king side open. Stockfish captured two pawns in the center but its king was stuck and could not castle while Houdini's king castled long. Houdini attacked through the king side with a QN combination, leading to exchanges and a RRB vs RRB position. Stockfish was still a pawn up but Houdini's rooks were more active. After exchanging a pair of rooks the extra pawn was not enough in an opposite color bishops setting.
In game 88 both kings remained in the center and queens were exchanged early. Houdini was a pawn up and Stockfish attacked through the king side, leading to a series of exchanges and a rook ending by move 28. Evals fell quickly to 0 and the game ended in a draw after most of the pawns were gone.
Game 89 started with black a pawn up, the queen attacking and pieces in awkward positions. The evals stayed low throughout the game, both kings did not castle but were relatively safe once the queens were exchanged. Only RRB vs RRN remained after move 28, and after a few pawn exchanges Stockfish ended the game with perpetual check.
In a similar position in game 90 Houdini offered a bishop sacrifice to open up the king side but Stockfish declined. After a series of exchanges Houdini was a pawn up in a double rook ending on move 31. The engines eliminated the queen side pawns, then exchanged a pair of rooks. The remaining rook ending was a draw but it took about 50 moves for the engines to agree.
Game 91 started with a closed Spanish opening, most of the pieces remained on the board with pawns mostly locked. Stockfish had a small eval advantage, perhaps a small space advantage and two knights that are stronger in closed positions. Houdini's bishops were quite miserable.
Stockfish's eval gradually increased though it was not clear why at first. Houdini exchanged knights, leaving Stockfish with one while Houdini had none. There were many weak pawns, both black and white, in particular the black b4 and g4 pawns could not be defended. After exchanging queens the black king side pawn line was broken and evals were over 1.5.
Taking its time Stockfish captured the b and g pawns, exchanging a rook pair in the process with RBN vs RBB remaining. Stockfish then sacrificed two pawns and created 3 passers across the board.
Houdini also had two passers but the white pawns were a more immediate threat. Houdini could not defend against all three without losing material. Stockfish squeezed a win out of this closed position, it is at +9.
In game 92 the engines exchanged more pawns and the position was more open. After opening the queen side both engines had a passer there. The engines exchanged queens and Stockfish gave the queen side passer and gained one in the center. Stockfish's eval at this point fell to 0, Houdini kept a small eval for a while longer. The game reached a RN vs RB position, Houdini kept one last pawn but it was not enough for a win.
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