Monday, June 25, 2018

Contempt

Earlier this year I wrote about how wrong it would be to shed Stockfish after his defeat against Alpha Zero (see to analyze using a computer part 3). In the last TCEC season 11 it became clear for everybody that this engine will still play a very important role at chess in the nearby future. First Stockfish qualified for the superfinal 7 points ahead of the number 2 Houdini. Then we saw a remarkable for this era of super-advanced engines a very one-sided battle. The convincing victory of Stockfish with 20 victories against 2 losses (for the rest only draws) was something we hadn't met anymore in the last decade.

The supremacy of Stockfish was probably the best shown in the double victory during the super-final when the Mar del Plata variation of the Kings Indian had to be played. First Stockfish won with the white pieces.
Next as for all chosen openings in the super-final, the colors were reversed for the engines (so no engine is privileged by the opening-choice). Again Stockfish won so this time with the black pieces.
After the match there was naturally a lot of talk about how Stockfish could make so much progress in such short notice. Hereby people quickly pointed to a new parameter of Stockfish: the contempt-factor. That needs a bit more explanation. First this parameter isn't new at all. Such contempt-factor exists for a long time but only recently the developers of Stockfish decided to use it intensively. The advantage is neither always obvious. In the previous TCEC season Stockfish made a bit too many draws against weaker engines which caused it to miss the final. As anti-dote the engine was adapted by playing moves leading to less exchanges of pieces so keeping the tension longer in a position which creates more scope for errors. Concretely this means Stockfish doesn't always play the best moves of its algorithms within an acceptable margin (defined by the contempt) to create more winning-chances. Besides this strategy is well-known in practical chess between humans see my article playing the man. However engine-play is very different.

The gain against weaker engines may not generate more losses against the strong engines. Nowadays a lot of experiments are done with a dynamic contempt instead of a pure static contempt see tests of Stockfish. They adapt the size of the contempt to the evaluation of the position. You could allow exchanges more quickly in an inferior position or the opposite.

So engines continue to develop. Also don't expect that Stockfish will rule the world alone in the future. Last month there was big news for its main-rival Komodo. The engine was acquired by chess.com see this announcement which will definitely boost the engine. The prediction already starts to materialize in the currently ongoing TCEC season 12 in which Komodo qualified as first engine and started the super-final with a win against the latest release of Stockfish.

For sure fans of engine-chess have something to look forward. Still this is and remains a niche which we see translated in the number of visitors. Stockfish is many hundreds of points stronger than the reigning world-champion Magnus Calsen. Nevertheless Magnus' games are 1000 more often viewed. For the regular chess-player an engine is only used to get an evaluation of a position or to make some analysis. As a consequence most just take the strongest available engine to do this job. Naturally it is a bonus that today this strongest engine so Stockfish comes without any charges.

However very few know that you need to be careful when using the latest version of the engine for the analysis. The evaluations are less accurate than previous releases of the same engine or of other top-engines if not interpreted correctly. That is because of the contempt-factor which influences the evaluations. When white's move avoids exchanges then a bonus of 0,2 is giving to white. For black such type of move would generate a negative bonus of -0,2. Such manipulations of the evaluation cause some strange yo-yo-effect especially at the beginning of the game. Even when no mistakes are made then we notice fluctuations of almost a half pawn. By applying the evaluation-profile of the Fritz-interface on a game with no serious errors, this becomes very visible.
Stockfish 9 with contempt (10 seconds per move)









These swings disappear in the first 20 moves when we make an evaluation-profile with the Fritz interface after resettting the contempt of Stockfish to 0. Below screenshot makes this again very clear.
Stockfish 9 without contempt (10 seconds per move)







This is our normal evaluation-pattern we need as base to comment games see annotations or to make some deep opening-analysis see to study openings part 2. For the analysis we want mainly an objective evaluation of how strong the moves are and not which moves create the best winning chances for Stockfish against other engines.

To eliminate the contempt can be done in the Fritz interface by looking up the settings of Stockfish. You only need to change the contempt-value from 20 to 0 see screenshot below.
Stockfish parameters
The only issue of this solution is that the Fritz-interface doesn't allow you to save this setting as default. So each time you start up Stockfish, you have to redo this. That is fine if you only use the engine sporadically but for intensive usage this is very annoying. On the internet I searched for a better alternative which I eventually found see stockfish 9 for analysis. There you can download a special compiled version of Stockfish more appropriate for analysis. In that version you don't need to reset each time anymore the contempt-parameter to 0.

It is not the only limitation of the default-settings in the Fritz-interface. I also don't manage to get the interface remember that it should not add my name as annotator. Each time I save any analysis, I have to remove manually my name. It is only 2 seconds work but in a couple of months this happens sometimes 1000 times so I am still wasting quite some time.
Another flaw in the default-setting is in the new application automatic analysis of the games played online at playchess. Recently I am playing again more blitz online (due to a lack of serious competitions). However when I want to check the openings of the blitz-games with an engine using the Fritz-interface see my article the (non-)sense of blitz then I am always disturbed by pop-up windows about tactical blunders spotted by the engine-trainer. It is today impossible to switch off this trainer forever.





There exist today other interfaces than Chessbase for engines but none can compete as they all have much less functionality. So Chessbase has an absolute monopoly which isn't good for the end-user. Today we see that the developments mainly happen around more functionality for the large community so they are persuaded of buying newer releases of their products. It is not financially interesting to optimize existing functionality for the few intensive users (they only make a couple percentages of the total customer-base). Besides few or no Chessbase-programmers are today active strong tournament-players see e.g. the interview with Matthias Wuellenweber in 2018. Playing professional chess and programming is a very difficult combination.

Brabo

Monday, May 21, 2018

Promotions part 2

After my game against Giovanni Callebaut played in the rapidtournament of Aalter see the memory I was exuberant. Obviously winning from a 1600 player is not very special if you are rated 2300. However it was how I won with a double rook sacrifice which pleased me enormously. This double rook sacrifice was on my wish-list for quite some time already (see e.g. game publications). The American grandmaster Gregory Serper even wrote an article about it see "typical patterns everyone should know double rook sacrifice" but he also admits that he never got the opportunity to play it.

His brother is of course the double bishop-sacrifice which destroys the king-side. Some examples of this famous theme can be found in chesscollection Double Bischop Sacrifices and in an article of the strong American grandmaster Daniel Naroditsky see "the double bishop sacrifice".  Beginning of this year I got the chance for the first time to execute it in a game. I am rather proud about that game although it just concerns an online one of 3 minutes each.
Other challenges on my wish-list are/ were e.g. a royal forka self-forkexcelsior,... These are all one by one exceptional themes. A less ambitious list can also be made as in the article "chess moves to play before you die". Besides it is also perfectly possible to add conditions when a goal is achieved. I guess probably all of us have once done an under-promotion if only to have some fun (be careful for the Nakamura-scenario see his game against Mamedyarov which I mentioned in my article jokes). Much harder is to find under-promotions which can be considered obligatory. Such example can be found in my article promotions. Very exceptional are the type of under-promotions which are not only mandatory but also unique. I mean with unique that the position does't resemble to anything earlier seen in practice.

On the site of Tim Krabbe there is an article "Practical underpromotion" which demonstrates how few examples comply to all above conditions. Well last I was astonished that 2 of such unique and mandatory under-promotions could've popped up in 1 of my most recent games. I write "could've" as the game was agreed drawn prematurely. Pity of course but understandable as I had just blundered a piece which spoiled the win. By using the computer I found the well-hidden pearls. I start with the most easy one.

Black sacrifices a bishop, 2 rooks and executes an under-promotion. Still it can go even crazier when white chooses for the critical move 32. Qf6.
 
Doubtless +3000 elo chess. The number of forced moves to keep the winning advantage in the different lines, seems too much as a human to calculate in a game. Besides it are almost all silent moves so without checks.

So a wish-list or bucket-list in chess can be something very different than winning ratings or titles. By the way except playing special moves it can also be just participating to some chess-activities. Personally I am looking forward to play together some competitions with my son. That can be in 1 team or in big international tournaments or maybe our first official mutual game.

Brabo

Monday, May 14, 2018

Queen-endgames part 2

After a flying start of Deurne in the Belgian interclub see my article records, people started to expect a lot for this season. Some thought the title was absolutely possible with our team. However still before new-year the dream was shattered. Defeats against the top-teams Jean Jaures and Borgerhout made an unbridgeable gap. In the second half of the season very soon nothing was left on stake for Deurne which probably explained why the results went downhill. With 3 consecutive defeats at the end of the season it ended embarrassingly. Deurne only scored 1 match-point more than the relegation zone. That is the worst possible result for Deurne in 20 years I am playing. Maybe we do have to admit that we lack young new players and the team/ club is slowly degrading. 4 years ago we were still playing in first division.

Nonetheless I played a good season myself. With 5 wins, 5 draws and only 1 defeat against the Russian grandmaster Vyacheslav Ikonnikov I was clearly the best performing player of the team and even Deurne. The 7,5/11 brought me 25 fide-points. I am satisfied with that score especially as I don't play much. Other rated games for fide I haven't played last year. On the other hand my other chess-related activities (see How much time do you spend at chess?) probably helps me to not become totally rusty. I can't compare myself with a standard inactive player just playing sporadically a game.

So my personal score was ok. Still things could've been even better if I extracted the maximum of often very nice positions in my games. After analyzing my games I realized that 5 extra half points could've been obtained with correct play. Nevertheless I have to add that finding the right moves isn't always easy at the board. We are no engines spitting out lines in just a nano-second. Some moves I missed as I lacked the time to find them. Others could be linked to an insufficient experience with the opening. Some I also think were simply too complex to calculate properly. An example of the latter was a beautiful opportunity which popped up in my game against the Dutch FM Bonno Pel. Queen-endgames are often not easy. In below position I was only able to detect the win by the assistance of an engine.
In queen-endgames part 1 I demonstrated the important role of the king in this type of endgames. Here we see another aspect of this endgame. The attacker looks for ways to transpose to an advantageous pawn-endgame. Not rarely keeping the queens on the board doesn't allow further progress so sometimes it makes sense to look for possible ways to exchange queens and enter a pure pawn-endgame. In above game I did that but only later. That allowed my opponent to avoid the pawn-endgame although technically it wasn't really mandatory. Often this is not a bad tactic if you don't trust the pawn-endgame as defending via checks is generally easier. I already mentioned this before in my article practical endgames see my comments at my endgame against Jan Gooris. Recently this was once again confirmed in the game Anish Giri - Yifan Hou played in Wijk aan Zee.
Besides Yifan already lost once in similar fashion a couple of years ago a queen-endgame against the world-champion Magnus Carlsen.
So in both cases the pawn-endgame was theoretically drawn but the number 1 of the ladies made a miscalculation. For us mere mortals it is therefore especially interesting to watch out for exchanges of the queens in this type of endgames. It can be an excellent winning try when all other normal resources dried up and the opponent is consuming its final energy-reserves.

Brabo

Friday, April 27, 2018

Fashion part 2

My previous article proved that there exists an enormous variety of openings. It is today completely impossible even as super-professional to know all existing deviations in your repertoire by heart. Nevertheless we shouldn't overestimate the value of openings especially at amateur-level. Many of my opponents don't play critical lines at all and just want to skip the opening to get a playable position in which the player with the strongest technique instead of memory can win.

I mean an ambitious player should rather focus the study of openings only at the critical lines. The many less dangerous systems can be checked too but in most cases it is sufficient to develop your pieces and get an acceptable middle-game. Besides even if you concentrate at the remaining important openings then still a lot of study remains as we can see by the testimonies of many professionals.

I believe it is not so easy for an amateur to make the distinction between important and less critical openings. How should I recognize which openings I need to study or which ones can I ignore? A coach can surely help here but not everybody has access to such luxury. In any case it is wrong to believe that openings played by higher rated players will automatically be more profound. As proof I checked my 100 most recently played games which I split in ratinggroups. For each of the groups I defined the average depth of the opening (linked to the deviation compared with earlier played games). I start with the games in which I had white.
For black we don't see any important difference.
So it seems there exists no link between somebodies rating and the opening-knowledge. No that is a wrong assumption. A higher rated player will have a better knowledge about openings. The confusion is created by the mix between opening-knowledge and opening-novelties. 99% of my opponents are followers. I mean that they will rarely use original ideas which are worked out at home in their openings. This isn't a surprise as the rating-groups consist almost exclusively of amateurs spending little or no time at doing individual research of openings.

The real pioneers and leaders of openings are of course our top-players and we should not forget correspondence-players. If we want to know which openings are critical then we should first check their games. This is something I do already for some years see e.g. how I described the preparation of my games in the article using databases or check my article the expert part 2 in which I stated that I focus at the games of +2600 rated players.

However keeping up to date the critical openings is something easier said than done as today we have more than 200 + 2600 rated active players. So every day there are novelties popping up which a professional needs to check. Last the Dutch top-grandmaster Anish Giri twittered that "If more than 2 twics are missing on your laptop then something went wrong in the routines." In my article how much money do you spend at chess I also wrote that I download at least twice per year the free twics but I don't have/ spend the time to filter all relevant +2600 games for my repertoire to study the novelties.

I guess for most amateurs it is the same. You can't expect amateurs working every day at their repertoire. Besides it doesn't make much sense. Much more interesting for us is to use summaries made by a professional which explains all the new critical opening-lines. This allows us to get up to date very quickly by a minimum of effort. Openingbooks and dvds are our first address to check. The disadvantage of those media is that they are very quickly outdated and can't manage to keep track of the latest trends. To really follow the fashion, chess-magazines need to be consulted preferably with the accent solely at openings. I recommend 2 subscriptions: chesspublishing.com and chessbase magazine.

Of course you will see quite some overlap between both magazines. Although different authors are working for the magazines, the same trends are noticed. That was last the case for the Armenian Winawer-line of the French defense Both published beginning of January a summary of the most recent developments in that system see chesspublishing January 2018 and chessbase magazine 182. Strangely I encountered the line already before newyear in my game against the Belgian expert Nathan De Strycker played  in the 56nd Christmas-tournament of Deurne.
I was lucky that my opponent couldn't remember well the analysis of this line as otherwise the game could've gone differently. As I don't have a subscription, I decided to make my own extensive analysis about the opening. I was surprised that this hypermodern-system is very playable for black see below the summary. I made my analysis using the modern monte carlo-mechansim so by playing many quick computer-games see my article computers achieve autonomy.
So now we finally know who creates new trends and how we can easily detect them. The next question is how interesting this is for the amateur. Well this isn't an easy question as I am not acquainted with the content of the magazines. I guess averagely once per year something could be useful for my standard games. That is not much but also largely depends on my own choices. I almost don't vary my repertoire as I use the scientific approach to choose openings. Also I play few games : I wrote 38 with a standard timecontrol last year in my article surprises part 2.

Briefly almost 100 euro per year for a magazine is a lot of money for me. For professionals the situation is very different. Last the Amercian grandmaster Alexander Lenderman grumbled with the famous Russian proverb "скупой платит дважды" after his painful defeat in 22 moves a week ago against the Amercian top-grandmaster Fabiano Caruana. The opening was treated in the most recent edition of newinchess yearbook 126 (this magazine is released only 4 times per year contrary to the monthly editions of chesspublishing and bi-monthly editions of chessbase) but Alexander missed it while Fabiano didn't.
My Russian father-in-law uses the proverb also regularly. A cheap person pays twice. Losing an extra half point in the US-championship can very well cost many times more than 100 euro see US-prizemoney and I don't consider yet other interests like qualification for the olympiad, the title,...

Let us go back to the mortals and it is doubtful to follow fashion in chess. There will always be players (mainly youngsters) being booked up by the latest novelties. So you do risk sometimes to play against a fashionista but don't panic as openings very rarely decide a game between amateurs.

Brabo

Tuesday, April 17, 2018

Which openings do my opponents play?

The answer which I gave at a reaction upon my previous article (see Dutch version of this blog) wasn't complete.  I wrote that the number of openings even with a very narrow repertoire is gigantic. But gigantic is something intangible. Can't we define a more concrete number? Well I'll give it a try with this article.

However before we start the number-crunching, we should first agree about the definition of what is an opening. I consulted multiple sources and discovered there exists no consensus about this. The summary by ECO (Encyclopedia of chess openings) is the only standard existing today but the system only categorizes the openings in 5 main-categories and 500 sub-categories. So ECO classifies openings but doesn't tell us what exactly is an opening or how many moves counts an opening.

In fact it doesn't really matter for this article as we are only interested in how far somebody can be booked up. In other words how many moves can a player memorize of an opening. Of course this depends of the player and the opening itself. I know quite some lines beyond move 20 see e.g. mistakes and copycats. Beginners often don't know more than just a couple of moves. World-class-players on the other hand sometimes know lines as deep as move 40. Still a high rating is not a guarantee of knowing much about an opening see surprises part 1. In short we don't know what players know or don't know and that is only intensified by many players consciously hiding their opening-knowledge see secret.

So I am obliged to arbitrarily draw a line for the opening. As reference I use the default settings to create an openingbook in Chessbase. On my blog I showed countless examples of my openingbook see green movesto analyze using a computer part 3studying openings part 2using databases, ... but nowhere I explained which settings I used to create that book.
Default (standard) 20 moves are used with a deviation linked to ECO. This means we use averagely 20 moves for an opening-line. More moves are used for lines in openings defined by ECO as popular while less moves are used for lines in openings defined by ECO as secondary.

So 20 moves will be used in my research as the base to define an unique opening-line. That finally allows us to check the openings played by my opponents. My personal database of standard games counts today +800. Let us see how often the same 20 first moves are played in those games or complete games if the game lasted less than 20 moves. An hour of scrolling through the database was sufficient to extract the answer out of it. The result was stunning. Only twice I got exactly the same 20 moves of an earlier game on the board. Besides I am pretty sure that these 2 unique cases can be fully linked to very deliberate choices of my opponents. In one game the Dutch IM Edwin Van Haastert copied my lost game played a couple of weeks earlier against the Belgian IM Thibaut Maenhout. It was a full scale battle with many mistakes but the final one was made by my opponent when he missed a devilish trick.
The second unique situation appeared in a game of the club-championship of Deurne. I already once won in 2009 against the 1700 player Pascal Francois. In 2011 Pascal repeated the opening as the opening is theoretically healthy. I agreed as there exists an important difference between the evaluation of the engine and the practical chances in standard play.
When we met a third time in 2013, Pacal had learned from the losses. You can't select an opening just by looking at the evaluation of the engine so Pascal deviated much earlier with an interesting alternative.

I want to return to the original question of which openings my opponents play. In the meanwhile we have the answer. Every game a new opening is played except some very rare cases. So we can't predict which openings will appear in the future. Therefore it makes little sense to study the openings of the opponents.

You could even state that it makes no sense to study openings at all at our modest playing-level. That was insinuated in a reaction of the Unknown One see article of 2012. However this is a bridge too far for me. In many openings it is an undeniable advantage to know a number of moves. 20 moves can be a good arbitrary line to define an opening but it tells very little how useful studying openings can be see my recent article the (non-)sense of blitz.

As each opening has its own very specific characteristics, I can't assign one number to the number of moves which one should know to get an opening-edge. Besides this also depends on the knowledge of the opponent as only crucial additional information of the opening will lead to an advantage. Therefore the second part of this article will be covering the effect of studying openings using the scientific approach which I apply in my games. How fast does the opening-knowledge expand when only playing a very narrow repertoire? I have more than 20 years experience with this method, so I can definitely show some remarkable statistics about it. In all those years I played exclusively the same openings and only made adjustments to the repertoire when a line was broken. Below you can see the evolution of my opening-knowledge in the standard games where I was playing white.
There is little difference in the evolution of my opening-knowledge for the black games I played.
In about +400 white and + 400 black games we see an average deviation at move 8-9 compared to earlier played games. In less than 200 of the +800 games I deviated from an earlier game so where I introduced something new which I learned from earlier made mistakes. It is remarkable that we see barely any progress of the deviation during the last 15 years although I kept more or less the same level of activity. So a couple of hundred games is not enough to create depth in somebodies repertoire. I assume my strategy could work for an extrapolated number of games. We saw this in the the project Alpha zero for which 44 million training-games were played. Naturally no human will ever be able to play so many games.

Despite averagely we see a very early deviation in the games, still in a substantial % of games the deviation from earlier played games happens later. I made a graphic about this to illustrate the % of played games linked to the move-number where the deviation happened. Below you see first the graphic of my white-games.
Later deviations occur less frequently in my black repertoire. This has to do with the Dutch opening which I play. White has a large variety of interesting lines in this opening which permits much more early deviations (I mentioned this already in my article a Dutch gambit part 2).
From the graphics we can deduct that in 27% of my white-games there is a duplication of the first 10 moves from earlier played games. For the black games this is only 16%. For the first 15 opening-moves we see that the share of white-games already shrunk to 3% while for the black-games to 2%.

I conclude this long article. The percentages are small but not negligible. Studying the openings of your own games will bring some dividends later. We all have different ambitions and priorities so there exists no rule about which amount of study is reasonable or not. Anyway if you study only for gaining some rating-points then I fear you will get disappointed in the long run.

Brabo

Monday, April 2, 2018

Surprises part 2

Last year I played 38 standard games of a slow time-control. I won 23 of them, made 10 draws and lost only 5. That seems a fantastic result but most of the games were played against weaker opponents. Besides only 11 were rated by fide so in the end I only gained a couple of ratingpoints. Many years already I can only play some small local tournaments to maintain more or less my playing-level.

Losing 5 games out of 38 is not much but each loss is one too many for an ambitious player. On the other hand losses are the best lessons to improve. That was part of the critics I received at chesspub because of my article to analyze using a computer part 2. Technically I make some high quality analysis but it is not clear how I learn something from it. Each game is unique (except in rare cases) so in each game new mistakes are made.

Of course something will be learnt from analyzing carefully games but often more can be achieved by looking to the total picture. Is there a common denominator in the mistakes? In my 5 most recent losses I noticed 1 important aspect. In each of the games I got very early into problems. In 2 games I even didn't survive the opening. 1 was already covered in my article evolution. The other was my game against Dries Janssen of which I already showed the final part in my previous artice.

No doubt my too optimistic play was a major reason for the defeat. Both kings stayed in the center but my king appeared to be much more vulnerable. However even more important to me is the fact that my opponent had seen the critical position already in his preparation. He was aware of a similar mistake made in that position see the game Haroon Azizi - Anneli Damau played in 2003 which also was countered by the same refutation (see moves 9,10 and 11). So aside from the technical mistake we should definitely focus at the disturbing difference of foreknowledge between both players. I am not yet even taking into account the rating-difference.

It is not a lack of study from my side. Earlier in the same year I had lost another game in the same opening. Because of that I had made an in-depth study of all the current theory. Of 5.h3 there exists only 1 mastergame in the mega-database but still I hadn't forgotten to check that possibility. Unfortunately during the game I wasn't able to remember my notes from that particular line. There were hundreds of them and 6 months later you just forgot most of it. I expect nobody can fully remember such analysis including absolute worldclass-players. Besides my analysis of 5.h3 were very superficial as the line can't be considered critical for the evaluation of the opening.

No my mistake was of course being too predictable for my opponent. I stick too much to the scientific approach of playing chess so my opponents can easily prepare a very dangerous surprise. I did some research of my games to illustrate this more clear. I selected all my standard-games which I played against somebody that I had played already once before with the same color. For this type of games I could assume  my opponents knew in advance my personality and adapted their opening-strategy to maximize their winning-chances. After filtering, 146 of my 829 standard games remained. It proves once again what I already stated in my article  matches that our chess-world is small. From each of the 146 games I wrote down which person deviated first from our previous mutual game(s) and at which move.
If we summarize then we see immediately a clear distinction between myself and my opponents. In 128 of the 146 games my opponent deviated first or in other words they tried to surprise me. Only in 18 games I was the one innovating from an earlier played mutual game. We also see this difference in the move where the game deviates from earlier play. My opponents averagely deviate at move 4 while I only do averagely at move 10. There is of course a connection between number of games and the move when the deviation happens. The next question is if my lack of flexibility costs rating points. Well I was surprised to find out that this isn't really the case. Below you see my TPR in the same rating-categories of my previous article.
Every medal has 2 sides. My lack of surprises is compensated by more experience. I also expect many players rather deviate to avoid a preparation instead of having made themselves a very elaborated preparation. It is again my negative remark of players being rather lazy than tired. Only for the highest rating-category there are doubts. The TPR doesn't decrease dramatically but I don't have a good stomach-feeling about my games. Especially Flemish top-players knowing me for decades will try to profit by using their preparation to counter my very narrow repertoire. So in that sense I do fully agree with the reaction at my article password of the Belgian IM Steven Geirnaert.

My article at the end of last year killer novelties indirectly proofs this with an example from my game against the Belgian FM Matthias De Wachter. Mixing openings is a necessity to improve which can also be deducted from  the almost 5 year old article the list of strength. On the other hand I do want to warn the reader that changing openings is not the holy grail either. In another loss this season the cause was definitely partly related by choosing a line which I hadn't studied earlier. I didn't know the mainline and my deviation was refuted by my opponent. So you can't play any unknown opening successfully to avoid being too predictable.

Brabo

Thursday, March 22, 2018

Comebacks part 3

In 2 years time my son Hugo managed to eliminate his original material-handicap. We started with 23 points (1 pawn = 1 point) as odds (see strange material balances part 2). Today only a (heavy) time-handicap (18 minutes against 1 minute and 15 seconds) remains. I find this surprising as I expected to still give bigger odds because I am almost 1000 points stronger. My son Hugo has only moderate technical skills so this situation is very different compared to the handicap-match against the Dutch expert Jaap Amesz which I mentioned in my article swindles.

I warned in my article sacrificing that often we sacrifice too optimistically. Today I want to refine my view by adding that even a small material-advantage in most cases will be decisive. Except beginners still dropping pieces, we very rarely see players recovering from a material-disadvantage. This sounds contradictory to what I wrote in my article comebacks. In that article I talked about 11 out of 100 of my games a deficit of 3 points was caught up. In 7 games even a comeback of more than 6 points happened with 2 extreme cases of 29,67 and 32,06 points.

The reason is that a computer-evaluation very often strongly deviates from the material-position on the board. Their evaluation is the final result of the critical line after both sides made the best moves. This final-position can deviate a lot from the actual position in terms of material if we are dealing with tactics. Sometimes those variations are extremely complex, making the engine-evaluation losing its connection to the practical chances on the board see annotations. It is another example of what I already described in my article to analyze using a computer part 2. An engine helps you to define very quickly your errors but then you still need to add the right interpretation to those mistakes. Unsurprisingly this often goes wrong, creating frustrations and aversion from the engines.

The difference between an engine-evaluation and a material-balance is clearly shown when looking at the comebacks. To illustrate this properly I again used the same 100 games of my initial article about comebacks. However I didn't just count the pieces on the board to make my investigation. Only when there was no clear compensation, I took the material-difference into account. Gambits or theoretical drawn positions can't be considered as comebacks. Below we see first the summary of my opponents.









Next is the summary for myself.










Only 5 pawns were recovered by my opponents in a total of 36 comebacks. I made up 13 points spread over 38 comebacks. So in most cases a pawn down meant a loss. Beside the exceptions can be almost exclusively linked to special cases. Or the position is tactically very sharp so a higher probability exists to recover from a small material disadvantage see my article the einstellung effect. Or the material is already very reduced so a higher probability exists to reach a theoretical drawn-endgame see e.g. my article practical endgames.

We can also assume from above tables that rating barely has any effect at the material-balance. I experienced this end of last year in a very painful defeat. I was obliged to win the last round of the maneblussers-tournament to get the tournament-victory and with the 1900 rated player Dries Janssen as opponent my chances looked bright in advance. However in an obscure opening-line I totally misplayed my position and very early lost a piece without any compensation.
Despite white surely didn't play the most quickest win, never the result was put in question. The handicap was far too big to ever hope to comeback. Besides my opponent wasn't a beginner either. Resignation immediately after losing the piece was a valid choice but something I couldn't cope with at that time. Also don't forget that it was 18 years ago that I lost another standard-game against a -2000 rated player see my article White chooses in the opening a drawing-line.

So you better don't get behind or your name must be Magnus Carlsen. Anish Giri didn't pass the opportunity to write a funny tweet about it: The world champion Magnus Carlsen is now officially a full piece stronger than the rest of the mankind. In other words Magnus can win against anybody even with a heavy handicap of a full piece.
Exceptions proof the rule. Miracles happen sometimes at chess so you do wonder if maybe it makes sense to continue always till mate. The American grandmaster Grigory Serper showed some other miracles in his article Why you should never resign? but leaves it up to the reader to decide when to resign or not at all. Personally I think it is dubious and mainly a waste of time to continue 100 lost games till mate just to steal 1 extra half point.

Brabo