Saturday, August 29, 2015

Season 8 group 1a after 8 rounds

With 8 rounds one game away from being finished the stage 1a scoreboard is now

In rounds 6-8 there have been more white wins than black, and the statistics now look more reasonable, 30% draws, 40% white wins and 30% black wins.

Komodo, Gull and Ginkgo will surely qualify, and so will Fire if it stays stable (apparently its hash and thread number settings have been lowered). For the remaining two spots my prediction is Texel and Protector. Arasan's performace has been admirable, including a draw against Gull. this suggests that its rating should be higher, but it is not enough for qualification. Jonny needs to win all its remaining games, and I doubt it can with its performance so far. Gaviota has some chances, but taking into account that it has an extra point due to Fire's crash I think it won't make it.

First points for Exchess! it beat Fruit in the battle for last place, but it also beat Gaviota which was a bit surprising. Gaviota chose an inferior defense 1. e4 Nc6, and paid for it. Game was a bit wild with advanced passed pawns on both sides, Exchess was able to convert the win in the end.

Fire played a very long game against Komodo. On move 3 Fire thought for 20 minutes, again raising questions about stability and bugs. It did not crash though. The game had several stretches of shuffling but Komodo found a way to win. Could Fire have held if it had a little more time or if it was a bit more accurate?

Jonny started its game against Protector with 8 pawn moves, resulting in the following position:

Weird opening... The pawn wall quickly disintegrated and Protector was able to punish Jonny for this adventure.

Notable game
Jonny - Fire, round 8
Game on TCEC archive

This was the position after Jonny's 13th move:

Black's king could not castle and the g6 square was inviting a fork. Indeed, after a few moves white completed a forking combination taking the h8 rook for two knights.

Jonny's evaluation jumped over 2, Fire was much more conservative at 0.56, but which was more accurate? White managed to invade the 7th row, after queens and minor pieces were exchanged:

Fire and Jonny's evaluation did not change a lot. Despite the apparent danger to black's king, Fire managed to hold the position and force a rook exchange. In the ensuing endgame the pawns were gradually removed on both sides until the black bishop walked into a trap:

Fire simply traded the bishop for a pawn, and the game reached a drawn R vs N ending. So Fire was right all along.

Thursday, August 27, 2015

Season 8 group 1a after 5 rounds

With 5 rounds over the group 1a scoreboard looks like this:

The ratings are starting to show, all the engines with elo>3000 are in the top half. Protector's situation improved considerably, including a draw against Komodo in a very long Q vs RN game. Jonny is only 1/5 but its losses are against top engines in this group and it may have a better record against easier opponents. Arasan is playing above its rating, though it is hard to see it qualify. Arasan lost to Komodo but it played well for 40 moves before Komodo could find a way to win.

The game that made the most noise was the Fire-Gaviota game in round 3. After a long battle Fire was clearly winning, even the win counter was close to adjudication, and then with 23 minutes on the clock Fire timed out and failed to make a move. This gave Gaviota an unexpected point, which explains its current place. Gaviota's ability to qualify is still in question. Fire didn't crash again yet, but it makes the viewers anxious every time it has a long think, including 16 minutes on move 1 in round 4. There's probably a bug somewhere, let's hope that Fire qualifies and gets a bugfix. It is a strong engine and it would be a shame to lose it on crashes.

In rounds 3-5 there have only been 3 (!) draws. The current draw rate is 30%, white wins 33% and black wins 37%. There have been a variety of openings according to ECO codes, for e4 games variations of the French are popular, and for d4 games variations of QGD. Only one Sicilian and one Ruy Lopez so far.

Notable game:
Round 3, Cheng - Komodo
Game on TCEC archive

On move 14 Komodo placed a strong knight on f4 making many threats on the king side.

Komodo expected Cheng to take the knight with its bishop, opening the g column for a rook. However, Cheng had other ideas, and it continued development on the queen side. Cheng continued to disregard Komodo's advice, ignoring the danger on its king side. On move 20 Komodo's evaluation started to jump. The knight was still at f4 but now the advice Komodo was giving did not invlove taking it since there were more urgent things to do.

Cheng's king side crumbled after several more moves and Komodo's pressure was converted to a win by move 34. The knight on f4 was still there (well, it moved and came back). Komodo: "I told you to take it, didn't I..."

Monday, August 24, 2015

Memorable Stockfish games, part 3

More memorable Stockfish games:
part 1
part 2

Season 6, stage 4, round 27, Stockfish - Houdini, Ra2
Game on TCEC archive

This game was played after half of stage 4 was over. After 8-RR Stockfish was at +6, Komodo was +4 and Houdini was +3. It was generally accepted that Stockfish was better, but Houdini was still a very strong opponent able to hold its ground, even against top engines.

After the 8 moves of the pre-selected opening each engine made its first move, and according to their evaluations there was nothing exciting going on. Then came Stockfish's 10th move:

Ra2. The crowd went slightly wild. The rook doesn't usually move forward so early in the game, and here Stockfish was hinting that it may use the empty second row to move a second rook to the king side quickly.The game continued with Stockfish preparing an attack on the king side and Houdini countering on the queen side. Houdini's evaluation remained drawish, it only started to sense the danger on move 18:

The rook is still on a2, waiting for its chance. In a few moves Stockfish opened the king side with a pawn attack, the evaluation skyrocketed, and then on move 25 the rook moved.

With so much firepower directed against its king, Houdini admitted defeat. The game was terminated on move 29 !!! Another WOW. In a match between two top engines this was almost unheard of. And of course there was Ra2. Ra2 was suggested in the chat as a move to change games around quickly, with laughs all around.

Season 8 group 1a after two rounds

Two rounds are already over, at a rate of about one round a day. Here is the scoreboard so far:

It's too early to think about qualifiers, Arasan and Gaviota with a better that expected result, while Protector and Jonny are diappointing so far. The openings have been diverse, and the draw rate so far is 50% with black winning 33% and white winning 17%. Letting the engines play from the first move is working well.

Jonny made a joke on move 1 of its game against Komodo. It started 1. e4, and evaluated this at 0.49! Komodo didn't laugh too much, it gradually turned the tables on Jonny, and converted a Q vs RB ending.  In Jonny's second game, black against Texel, after 1. d4 d5 Jonny evaluated 0.57, not so funny this time. I think the evaluation function needs to be examined.

In the Komodo-Gull game two of the favorites of this group met. The game ended in a draw, but there was one interesting event starting at move 35. Suddenly without warning Komodo's evaluation jumped for two moves, as if it saw a win. And then it returned to drawish values. But then Gull's evaluation did the same. According to this effect we can estimate that Komodo sees about two moves farther than Gull.

Notable game
Of the games I followed in these rounds the one I enjoyed the most was the Gaviota - Protector game.
Game on TCEC archive

Gaviota the underdog maintained a small positive score, and when it saw its chance it launched a furious pawn attack against black's king, here after move 30:

Just look at black's miserable bishop. With black's king stuck in the corner and the queen as its last defender, white launched an attack on the f7 pawn:

A final knight maneuver cracked black's defense for the win. Congratulations to Gaviota and its author Miguel Ballicora, always a welcome participant in the chat room with a lot of insightful commentary.

Saturday, August 22, 2015

Season 8 is here !!!

After a long wait it's finally here !
It's really been too long, though now that it's here will I have time for other things?

There are some novelties this season:
  • The tournament left Martin Thoresen's appartment and is now hosted by Chessdom. I noticed that they even changed the meaning of TCEC = TOP Chess Engine Championship. For me Thoresen will always be part of TCEC...
  • New hardware with 20 cores. I'm not a hardware expert, the talk in the chat has been that although there are more cores than before they are slower, and the overall speed benefit is small. There are rumors that the final will be played with 40 cores, we'll see.
  • Time control for the first stage is 90 minutes per engine plus 30 seconds per move. This will increase in the next stages by 30 minutes per stage, up to a monstrous 180 minutes per engine in the final. I think this is too long - every game in the final will take 7-8 hours.
  • The final will consist of 100 games. At a rate of 3 games per day it will take a month to finish - I told you it was too long...
  • The first stage will have no preset openings. I really enjoyed the no opening stage in last season, very happy they continued with this idea. The next stage will have short 2-move openings, and after that 8-move openings will return.
The first stage is divided into two groups. Group 1a contains Komodo, Gull, and Fire, group 1b will feature Stockfish and Houdini.

May the best engine win, and fun for all !!

Friday, August 21, 2015

Memorable Stockfish games, part 2

More memorable Stockfish games:
part 1
part 3

Season 6, stage 1b, round 6, Stockfish - Fire, the F stack
Game on TCEC archive

Stockfish and Fire were the highest rated engines in the first stage group 1b of season 6, which made this game one of the highlights of the stage.

From very early on in the game Stockfish had an evaluation higher than 1.5 and growing as the game progressed, while Fire's evaluation was around 0.7 and generally constant. Fire couldn't see its danger, and the question was how Stockfish will get the win. By move 45 Stockfish is a bishop up with almost no pawns but Fire still has a queen and rook, the winning path is not clear. Even though Stockfish's evaluation is over 4 it's principal variation does not look immediately winning. Checking a 6-man tablebase shows that if we remove the rooks and pawns the position is a draw. Is this what Fire is telling us?

After 11 more moves the game reaches this beautiful position which made this game so memorable to me:

Almost all pieces are stacked on the F column!! Stockfish sees a clear win now, but Fire still thinks its not in real danger. The illusion is broken on the next move, Fire's evaluation jumps to 4.77, and in a few more moves Fire loses its rook for a bishop and the game is over.

The analysis of this position is far beyond me. To my mind only engines can venture into such positions, and as we see in this game only the top ones manage to analyze them correctly.

Wednesday, August 19, 2015

A short history of TCEC, part 2

This is the second and final part of the history of TCEC, so far.

A short history of TCEC, part 1

Season 6:
Before season 6 (the nTCEC numbering was abandoned) started the site was redesigned to what we have today, a new system for choosing openings was implemented with the help of Nelson Hernandez (aka Cato the Younger),  and Syzygy 6-man tablebases were added for the benefit of any engine that could use them. Stockfish and Komodo were updated constantly as always, and Houdini had a new version 4. Komodo's tablebase use was introduced in the later stages of the season.

In the first stage the engines were divided into 3 groups of 12, each group played a RR, the top 5 qualified as well as the best 6th place for a total of 16 qualifiers. The second stage was again a RR with 8 qualifiers. The third stage was a 4-RR with 4 qualifiers: Stockfish, Houdini, Komodo and Critter (tiebreak for fourth place with Fire and Gull, Rybka a distant 7th place). The fourth stage was a 16-RR, Stockfish won and Komodo came in second, their mini-match result was a draw 2-2. Both engines beat Houdini in this stage, 4-2 and 4-1 resp. Critter, which was no match to the other engines, was a distant fourth.

The final match between Stockfish and Komodo had 64 games. This time Stockfish's dominance throughout the season continued in the final. By game 18 the result was 4-0 and after game 28 it was 5-1, after game 40 it was 9-3, the end result was 13-6 with 45 draws. After two second places Stockfish was the champion of TCEC season 6.

In the break before the next season starts TCEC hosted a short Fischer Random Chess (Chess 960) tournament. This was interesting and weird, the non-canonical start positions generated chess games that had a totally different flavor to what we are used to. There were 8 engines in the tournament, playing a 4-RR. Stockfish proved to be almost invincible in this tournament, with a final result of 25 points out of 28 and only one loss.

Season 7: 
Tablebases were disabled completely in this season, except for game adjudication. Houdini stayed with the same version as season 6, apparently its developer abandoned the project. Stockfish and Komodo continued to be updated regularly. For the first time Rybka did not participate.

In stage 1 there were two groups of 14 engines, each played a RR and 7 qualifed for the next stage, a total of 14 qualifiers. The second stage was a again a single RR, but this time with no imposed openings, the engines were on their own from move 1. The 8 qualifiers played a 4-RR in stage 3, Stockfish, Komodo, Gull and Houdini were the qualifiers. The fourth stage was a 12-RR, Komodo won and Stockfish came second. Many of the Gull games were decided in this stage, and their result had a significant influence over the end results. Gull mini-matches against Stockfish and Houdini were drawn 4-4 and 3-3, but it lost to Komodo 5-1. Most of the other games ended in a draw, Komodo beat Stockfish 2-1 and Houdini 2-0, and Stockfish beat Houdini 2-1. Of all fourth stages over the seasons the results for this season were the closest, and the identity of the second qualifier was not assured until the final rounds.

The final between Komodo and Stockfish was a 64 game match. All through the season Stockfish was not as convincing or as dominant as the previous season. It was often behind on time, even against weaker opponents. This was also a feature of the final match. After game 16 Komodo opened a 3-1 lead, increasing to 5-2 after game 40. Stockfish managed to reduce the gap to 5-4 after game 56 but Komodo came back to win 7-4 with 53 draws, including a win in the final game (Stockfish seems to give up the last game, happened in three of four finals). Once again Komodo was the TCEC champion.

There was a long break after season 7, much longer than was initially announced. I don't know what went on behind the scenes but things are now back on track, and we are waiting for Season 8 to start, writing a new chapter in the history of TCEC...

Monday, August 17, 2015

Memorable Stockfish games, part 1

I am a Stockfish fan. I'm not a fanatic who thinks it should win every game, and I have nothing against other engines. I find the idea of an open source engine very appealing and a miracle that it can be developed by many collaborating programmers without being slowed down by bugs. When I started watching TCEC it was the new engine on the block, the underdog, and it finished a close second. In season 6 it was nearly invincible with a quick offensive style that was great to watch. In season 7 it had many disappointing games, and it made me feel frustrated. I don't get as emotional watching other engines play, it's just the way it is.

In the past 4 seasons there were many beautiful chess games in TCEC, usually I forget them after a few days. There are a few Stockfish games which I remember, not the specifics but a move or a situation which amazed me, made me stare in disbelief, enough to be stored in my long term memory. In this list of posts I will present these games as best I can.

Other Stockfish memorable games:
part 2
part 3

Season 5, stage 4, game 6.3, Stockfish - Houdini, +10 difference

Game on TCEC archive

This was the second game between Stockfish and Houdini in this stage. The reversed game ended in a draw without special events, and this game appeared to be uneventful as well. The pawn structure had been almost static for the past 15 moves, both engines moving pieces without any apparent aim. Then Houdini played 38 ... Rf4 with less than 90 seconds of thinking.

WHAT? Why is Houdini offering a rook? And being so cool about it? Apparently it thinks that after taking the white knight it can create enough pressure with the queen and knight to compensate, maybe get a perpetual check.

Sure enough, for the next 10 moves Stockfish goes along with the exact plan Houdini shows in its principal variation. At first Stockfish agrees with Houdini's evaluation, but at move 42 the score jumps to 2.18 and at move 46 it jumps to 7.33 !

Stockfish is convinced it's winning and Houdini can't see it. On move 48 Stockfish's score reaches 10.88, and Houdini still thinks it is safe. This +10 points difference is amazing. Only now does Houdini think hard and it realizes that white can escape the perpetual and the d pawn is unstoppable.

The game was over after a few more moves.

The huge difference in scores, the fact that it took Houdini 7 moves to realize something was wrong with its plan, long after Stockfish thought it was all over, all this was a clear demonstration of Stockfish's superiority over Houdini.

A short history of TCEC, part 1

Seasons 1-3:
I have no idea about these seasons, I wasn't aware of TCEC back then. Looking at the archived games I don't understand the format. The first two seasons ended in a 40-game match Houdini - Rybka, both of which Houdini won convicingly. The third season was interrupted for some reason and there was a break of about a year and a half.

All this happened before 2012, this isn't history, it's archeology...

Season 4:
The 4th season was called nTCEC (new TCEC) season 1. I remember the colorful design, graphs of green and purple against a dark background. Here are some partial screenshots I found on the web:

The first stage was a 32 engine 7 round swiss tournament. The 16 qualifiers were split to two groups of 8, and each group played a double round robin, each opening played twice, reversing black and white (This color reversal is a constant feature of later stages of TCEC, allowing the comparison of the two games in a mini-match, as well as reducing the effects of biased openings). The best 4 from each group qualified, and another double RR was played to determine the best 4 engines. Houdini and Rybka qualified of course, as well as Stockfish and Komodo. Stockfish was the new open-source project which everyone liked because it was able to hold its own against the old champions. Komodo was a surprise, a single core implementation at that time.

The final-4 stage was a 6-RR, where each pair of engines played 3 openings and their reverses. Houdini won, Komodo came last, but Stockfish managed to qualify before Rybka. Rybka's result was 16 draws, one win against Komodo and one loss to Stockfish. It was not developed anymore and found it hard to keep up at the top level.

The superfinal was a 48 match between Houdini and Stockfish. Houdini had a 3-0 lead after 14 games, Stockfish got one back and then managed to draw 4-4 by game 28, after beating Houdini in the French advanced opening on both sides of the board. In the remaining 20 games Houdini managed to win one and keep the lead until the last game, where it won again to reach a final score of 6-4 with 38 draws. Houdini was the winner, but it was very close.

Season 5:
After a short break of a few months, nTCEC season 2 was started. Stockfish had a new version, and was still updated each stage. Komodo could now run on many cores. Houdini started with the same version, but had an update in the final stages.

The first stage was a 36 engine 7 round swiss tournament. There were supposed to be 18 qualifiers but due to a bug in the software it couldn't handle an even number of participants and an additional qualifier was used. The second stage was a single RR with 10 qualifiers, the third stage was a double RR with 6 qualifiers - Komodo, Bouquet, Houdini, Stockfish, Gull and Naum. Rybka missed qualifying to the final 6 on a tiebreak.

The fourth stage was a 6-RR. Stockfish won, beating all opponents without loss, including 3-0 over Houdini and 1-0 over Komodo. Komodo managed second place before Houdini, mostly because of a better performance against the weaker engines (they drew their 6 matches). This stage coincided with the 2013 Anand-Carlsen world title match. TCEC had a special page covering the match with computer analysis by Houdini, Stockfish and Komodo which I remember watching. The chat was shared with the regular TCEC, causing the many spectators who came to see Anand and Carsen to be confused by comments on some computer chess matches they weren't aware of.

The final between Stockfish and Komodo was again a 48 game match. There were many decided games at the start, the result was 4-4 after 12 games. Komodo had the lead after game 18 and extended the lead to 8-4 after game 28, including a double win in the Indian: London system opening. Stockfish gradually got back to the match, with three wins and a 9-8 score after game 44. The match ended with a deja vu win for Komodo in the last game, a final score of 10-8 and 30 draws, and Komodo was the winner. Again a very close match and a second loss for Stockfish in the final.

Next: A short history of TCEC, part 2

Saturday, August 15, 2015

What to expect from Season 8

Season 8 is approaching fast, perhaps starting next week. Before it starts I thought I'd list things I expect will happen, based on past seasons.

First, unlike previous seasons the tournament will be hosted by chessdom. I'm not sure what that means in practice, perhaps the hardware will not be in Martin's appartment. Judging from the last few months one effect is that communication with the community has suffered. The season start was postponed with no explanation, and similarly for announcements made regarding schedule. In previous seasons the process was much more open to the public, the chat was filled with discussions about engines, openings, the format etc. There were even public polls to help decide specific format questions. Things seem to be more official now, I hope this doesn't affect the entertainment value of the tournament.

And now, the list:
  • The chat will erupt in furious arguments about various topics: How many plys should openings have? Should there be fixed openings at all? Is using tablebases good or bad? Change the adjudication criteria! Shorter or longer games? Stockfish or Komodo? Open source or commercial? Are Houdini/Rybka/Ippolit/other the good guys or the bad guys?
  • The chat will be hit by trolls, some annoying, others amusing.
  • Angry responses from fanatic Stockfish fans if it loses, god forbid.
  • Engines will crash in a few games in the first stage, really annoying the crowd and causing an unfair advantage for the engines they happen to be playing.
  • There will be a tight race for the last places of the first and second stages, only for the engines that manage to squeeze in to be crushed in the next stage.
  • The finalists will be Komodo and Stockfish. How far Houdini can go (no update in two years?), how much has Gull improved, will there be a surprise in the top engines, all remains to be seen.

I am looking forward to all this and more, as the live site now says: season 8 is coming...

Friday, August 14, 2015


Welcome to my new TCEC Experience blog. This is my first post (ever) and I will try to explain what this blog is about.

What is TCEC?
TCEC - Thoresen Chess Engine Competition - is a computer chess tournament organized by Martin Thoresen. The Wikipedia page contains information about the format and the history of the tournament. The main page of TCEC broadcasts the games when they are played. It also links to an archive of all previous games and tournaments, a facebook page for news, the rules of the tournament, a chat box for live comments and more. If computer chess interests you, I urge you to visit the TCEC page.

Are you a chess professional?
Far from it! I have basic chess knowledge and haven't played games since I was a young boy. Simple chess engines defeat me regularly. Watching games on TCEC and reading what experts have to say has added a lot to my chess education.

Watching computers play chess is boring !?
I agree it is a bit strange. Ever since I started watching TCEC (season 4, 2013) I found that chess could be a spectator sport, and the live broadcasts can be highly addictive. It helps that TCEC lets you see what the two engines are planning, their evaluation of the position and how hard they're thinking. The human commentary and fans shouting in the chat box adds to the overall experience. Try it: you may find that it's not boring at all.

What about humans playing chess?
Watching TCEC has increased my interest in normal 'human' chess. The big tournaments usually have live broadcasts and human commentary from real experts as well as computer analysis. It can sometimes get very exciting but usually for 'human' reasons. When players get into time pressure they can blunder terribly, things you don't see in computer chess. Another feature is when one player prepared a line and plays instantly while the other has to think a lot. Computer chess also has its annoying elements, such as an engine playing many meaningless moves without realizing that a position is drawn even though it has some small advantage in material or position. All in all I prefer the computer version. Also, I think it is agreed now that computers play better than humans.

What do you plan to post here?
The 8th season of TCEC is starting in a few days. I hope to have time to watch the games and to post my impressions. Since games are played 24/7 I will not watch everything live, I do have a family and a job I would like to keep. If I have time I may post reports of archived games from previous seasons that I enjoyed watching.

Why not use the TCEC chat?
In the chat it is too hard for me to write and to keep up with all the discussions going on. A blog lets me control what I want to say, and I have the time to say it. It also allows keeping a page on a specific game or topic, so it is possible to return to it later, where in the chat it is very hard to go back to what was written yesterday or last week.