Tuesday, September 30, 2014

The horizon

If there is a red line in my chess then it must be that I try to avoid chance as much as possible. This can be seen e.g. in a reaction of Kara in which he expresses his surprise about my depth of preparation. In my article which games to analyze I explain in detail how I try to extract lessons from the analyses. Again I try to arm myself against haphazard repetitions. In my OTB-games you can clearly see an allergy for risks to avoid that the result depends too much on luck. For this I already once received right or wrong critique see Lintons reaction on the article Tactic.

However assuming that I always avoid risks is nonsense as I am e.g. no pragmatic player, see chessintuition part 2 or somebody never daring to play a gambit. Now I do admit that the balance clearly leans to prudence and especially playing economically. Playing economically was already once touched in a reaction of my article my most beautiful move. If I can choose between sacrificing material of which the complications are obscure and between (preferably without spending much reflection-time) a quiet continuation which still permits to maintain a position with some prospects then I choose invariably for the second option.

So it happened in round 5 against the British player Andrew Stone that I after a long reflection anyway didn't sacrifice my knight but preferred to retract it to f6. I imagine MNb will probably be shocked again if he sees that I once more chose for the retracting move but sacrificing somebody else's pieces is always easier.

After the game it took me a lot of effort to verify the piece-sacrifice but now I dare to state that it is fully correct. However I would not mention this if there was nothing special about. When I let the engines Houdini 2 and Stockfish 4 calculate on the critical position then none of them found the key-move even on my fastest PC. Something like that I hadn't encountered before with those programs. Was it still possible as human to find a tactical idea at the board which was beyond the horizon of the best engines?

Via the wikispace of testpositions for chess-engines I tried to find recent examples from the tournament-chess. However I didn't have much luck as everything which I checked was pretty quickly solved by my top-engines. E.g. also the testposition 201 out of  the standard arasan testsuite. This is an extract from the game Hikaru Nakamura - Anish Giri played in the 2012 Fide Grandprix at Londen.

Therefore I also looked at some positions from older games which some testers use. One of them was a critical position of the famous game David Bronstein - Ljubomir Ljubjevic. I recently bumped by accident on this game when reading My great predecessors part 2.

It is naturally not because I can't find immediately examples from the tournament practice which engines can't solve that they don't exist. However from an older blogarticle Shirovs brilliant Bh3 we can deduct that the examples are not widely spread anymore. I am curious if there are readers knowing such specific positions from practice or maybe encountered them when analyzing their own games. At chess problems composers often work several days which permits sometimes still to fool the best engines. An example of such puzzle I found on a forum in which white gives mate in 60 moves !

Of course this is not a normal position anymore but it does show that the human player isn't fully defeated by the engines. In the category of exceptional positions certainly belongs also the position of my game. The temporarily locked bishop on h1 and the preliminary control of the critical square h6 are a funny concurrence which engines today can't handle. To be more precise the HW and SW which I use today can't. Some readers certainly possess stronger equipment which maybe can sufficiently shift the horizon so a different image is created.

Brabo

7 comments:

  1. As a correspondence chess player I could probably speak for hours about the chess engines and their evaluations of different positions. The overall opinion of most of the OTB players is that engines are so strong, that no human can "argue" with them. And I can only smile when even strong OTB players ask me how can I play correspondence chess in these modern times where everybody uses strong chess engines and fast computers. As I am too tired to explain through and through in which positions the computers are weaker than humans and why, I won't do it here, too. I won't speak. Instead, I prefer to show you a game played in late year 2012, a correspondence chess game between two of my countrymen-colleagues who both played it with engines' assistance. The first player is a FIDE IM, while the second one....well, just an engine operator, as it seems: https://www.iccf.com/game?id=357514 The first game shown here on this page, somehow reminded me of the game I just posted. You can copy and paste it in your chess software, run your engines and see their evaluations! And you'll understand what I mean!

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  2. My title seems to be misleading if I interpret properly your reaction. Yes long term advantages like in the game you show are clearly beyond the horizon of an engine but that is not the idea of the article.
    With the article I am trying to discover if there exist still positions in which a human can outsmart an engine in pure tactics so without getting any external help to calculate. The example that you give doesn't contain tactics like I show in my article.

    I am interested in OTB games in which this tactical horizon is demonstrated. Also I don't want to consider correspondence games as there is no clear line between human input and engine output.

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  3. First there were the Nolot positions, of which the Bronstein - Ljubjevic position is a member, which were famously difficult for computers to solve. Even Deep Thought, the predecessor to Deep Blue, analyzed them. Nowadays, however, they've all been solved, some of them trivially, or been proven incorrect. The toughest was probably 13...axb5 from Malaniuk - Ivanchuk, 1988, but it has now been solved in the last few years. Shirov's ...Bh3 was another long-time hurdle, but has been found by engines too as you know.

    One more famous position that has been resistant to computers has been Gusev - Averbakh, 1946. 4q1kr/p6p/1prQPppB/4n3/4P3/2P5/PP2B2P/R5K1 w - - bm Qxe5

    Nevertheless, a combination of Houdini, big hardware, and probably a little bit of luck managed to find that one as well after searching 33 billion positions. As you say, it's getting tougher to find a deep tactic that can stump engines for long.

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  4. Engines' parameters can be modified to exclusively find tactics in practically every position. So, they are able to find every tactic blow, in fact....but only if a human knows there is one in a specific position and let them find it. Strong correspondence chess players know this and when they "smell something", they let them loose. By the way, Houdini 4 in tactical regime is not the strongest one in this specific area. There are several others that can do better job. Anyway, the problem is that one can't always analyse with a modified engine, because when modified, such an engine is slow in calculating. So, being a strong OTB player (who can "smell something" in a concrete position) is obligatory to become a strong correspondence chess player.
    As for the tactics themselves, we all know that tactics are not only sparkling blows and sacrifices. Long time strategy tactics are what the engines can't solve, for now. For example, Topalov's favourite quality sacrifices which only change the balance and can be crucial (or not) in the long run, sometimes 20-30 moves ahead. Such tactical strikes are difficult to be properly evaluated by the today's engines, because they prune variations much sooner, if not "seeing" fast results. One specific case is when, as a result of a little pawn sacrifice or alike, an opponent's piece is isolated for a long time. That's why I showed the above game, probably inspired by the game brabo analysed here.

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  5. "Engines' parameters can be modified to exclusively find tactics in practically every position. "
    I agree but again this article is about using an engine without modifying anything at all. I am comparing pure human power with pure engine power. B.t.w. the analysis published in the article is clearly a cooperation between human and engine. I didn't play the move in OTB although I did see a major part of the variations without any help.

    "Topalov's favourite quality sacrifices which only change the balance and can be crucial (or not) in the long run, sometimes 20-30 moves ahead."
    For me these are positional sacrifices and not tactical ones. In my game it is a tactical sacrifice as whites counterplay on the queen-side can easily unlock the bishop of h1 if blacks king-side attack is not fast enough. The mainlines are only 10 moves deep often ending with mate so pretty amazing that today's top-engines have so much troubles finding it.

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  6. Not sure if this is directly relevant but chessbase recently also published an interesting article on this point. http://en.chessbase.com/post/hartmann-choosing-a-chess-engine

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  7. If you want to read the original version of the chessbase article then you have to use a different link: http://chessbookreviews.wordpress.com/2014/09/11/choosing-a-chess-engine/

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