Better than an engine: Leonardo Ljubicic (1/2)

by Martin Fischer
2/21/2016 – Leonardo Ljubicic is the 28th World Champion in Correspondence Chess. In an extensive interview he talks about his way to the title and reveals how he prepares for his games. He talks about his openings and what is important to play successful correspondence chess and explains how humans use engines to play better than engines - an art and a science.

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Leonardo Ljubicic

You are the 28th World Champion in Correspondence. Tell us something about your background.

I am 49 years old, married, and father of three children, two sons (23, 17), and one daughter who is 20. I live in Omiš, a small, beautiful town at the Adriatic Coast, about 25 km south of Split.

I think I learned to play chess when I was about nine years old. In 1977 I played my first club games and my name appeared for the first time in the archives of our local chess club. Around that time I also started to play correspondence chess.

My father Ante was a high school teacher of mathematics and a chess enthusiast. He was also the alpha and omega behind our local chess club and a keen correspondence chess player. I got addicted pretty fast to both disciplines: over-the-board play and correspondence chess. If I recall correctly, my father thought that to play correspondence chess at such a young age would help my chess and my character. It would teach me to organize myself (order and a systematic approach is needed to keep track of all the games and the many postcards that kept coming in bringing new moves) and to be more patient. It worked!

I also noticed very early that time pressure was my greatest enemy in over-the-board chess, and here correspondence chess came in very handy. Correspondence chess also helped me to explore the laws and theory of chess deeper.

You are not a chess professional. Is your work and profession related to chess?

Indeed, for me chess is “just” a hobby. I studied to become a Mechanical Engineer, B.Sc.., but during the course of my career I have worked in all sorts of managerial jobs, and thus I think I might best be seen as an expert in business administration and marketing. But no, nothing connected to chess.

The final of the Correspondence Chess Championship was a 17-player round-robin tournament, in which you scored 10.0/16 to become clear first. Modern correspondence chess is very different from the time when you made the first steps in correspondence chess. What has changed and how are todays’ World Championships organised?

Outdated: a postcard for correspondence chess

Correspondence chess has indeed evolved over the years. We don’t use postcards anymore but play on the webserver of the ICCF, the International Correspondence Chess Federations. The players come from all parts of the world and are members of their national federations – very similar to the organisation of OTB chess.

What FIDE is to OTB chess, the ICCF is to correspondence chess and they adhere to a strict set of rules that govern play in general and play in tournaments. With all due respect to many chess servers, the ICCF is by far the world’s most serious place for online chess. We have a wide range of tournaments, world and zonal championships, team Olympiads, friendly matches, invitation, class and promotional tournaments, world cups, and so on. There is also a small but ever growing group of players who play Chess960. The ICCF maintains its own rating list, officials and national delegates meet every year to discuss and, if necessary, revise rules and guidelines, and to talk about the development of the server and correspondence chess in general.

All in all, I would say the ICCF made a well-balanced and timely transformation from the age of postal chess to a contemporary, modern and respectable organization that keeps the spirit of correspondence chess alive.

The World Championships are played in cycles. Every year a new cycle starts and finals are played every two years. The standard time control is 50 days for 10 moves and competitive tournaments are finished within a period of two years – though not every game lasts that long.

You have to pass three preliminaries (Preliminaries, Semifinals, Candidates) successfully before you can play in WCCC Final. However, if your rating is high enough or if you hold a prestigious title you might enter the cycle in the Semifinals. So, on average, you need four to six years to qualify for a world championship final.

However, that is not easy task: not surprisingly, world championships are the strongest series of tournaments within the ICCF. The Preliminaries are typically category III tournaments (2300+), Semifinals are already category VIII (2425+) tournaments, and if you somehow manage to win both levels you qualify for the Candidates – which is essentially a horrible place to be J. Here the absolute best, the most promising and the most agile compete. The Candidates usually are category XI-XII (2525) tournaments and only the winners and sometimes the players finishing second qualify for the final.

Hard work but fun

How did you qualify for the final?

Up to 2007 I was merely a casual CC player, indulging myself in human-computer interaction, lingering around 2450 level. But I had once played a Candidates tournament and despite my decent result I was overwhelmed by the sheer strength of the 2600+ players I had to play against.

However, I had qualified for two more Candidates and I remember that one day in 2008 I had a long and hard thinking session wondering whether I should really give it a shot or not? I finally decided to go for it but I knew that it would never work unless I gave it everything – my free time and the “machinery”. At that time my kids were already half-grown and after my wife reluctantly gave me green light to go ahead I equipped myself with an early version of a 4-core PC, acquired all sorts of opening books, databases, and the Nalimov five piece tablebases – I thought it was necessary to cover all phases of the game with the best the chess world had to offer.

I then entered the two Candidates tournaments I had qualified for simultaneously, hoping for a success in one of them. I prepared and played seriously in both and the result was overwhelming: I won both tournaments and became a grandmaster doing so. However, I was too late for the final of the 27th WCCC 27 Final and had to wait till early 2013 to receive and accept an invitation for the 28th final. All in all it took me about five to six years of serious work and play to reach that stage.

But the finals were really time-consuming: I invested about twice the time I would usually invest in a standard category XIV tournament.

Today chess engines are much stronger than the best humans and many people wonder about the role of humans in correspondence chess. What can you do that the engines cannot do?

It is indeed impossible to achieve any significant result in today’s correspondence chess without engines and databases. But we humans play, not the engines, and the input of humans mainly affects two areas: a) the choice of a suitable opening, and b) steering the engine toward (or away) from certain types of position.

If you want to be successful in top correspondence chess you can only play a certain set of openings because you simply cannot afford one single sub-optimal move – if you do, you will sooner or later regret it. That’s as certain as death and taxes.

How well you guide your engines depends on your general chess knowledge. The better your chess knowledge (the significance of pawn structures, good bishop, bad bishop, etc.) the better you will do here – today’s engines are very strong but they still misjudge positions. If you have enough time and patience and composure you can feed the computer with more good ideas than your opponent – exactly the process described by former World CC Champion GM Ron Langeveld in an interview on the ICCF website.

I used Rybka for a number of years but around 2012 and 2103 I switched to Stockfish. Of course, I tested other engines as well but these two are my main engines. I firmly believe that the top CC players must not change their engines too much because you have to understand and recognize the strengths and weaknesses of your engines. Otherwise, you again and again have to choose between two or three moves the engines suggest, however, without understanding the differences these moves.

In my case, this would basically mean that I, as a player with a FIDE rating of about 2200, had to evaluate the moves of several 3300+ “players”. That cannot up well. If you stick to one engine you gradually get to know it better, you know where it is strong, you know where it is weak, you know, which positions it plays well and which positions it does not like.

But you should not let the engine do all the work, for instance, by giving the engine a certain position, then leave the computer for a couple of hours, and when returning just check what the computer proposes. You will do much better if you watch the thinking process, to try to recognise and understand the strengths and weaknesses of the machine and to guide the analysis.

You also need a lot of patience! If you are unsure what move to make, wait – and sleep one night over it. Use your 24 hour time buffer. Let the engine finish the iteration. All top engines today prune very heavily, so using the “Next Best” function is the main tool for correspondence play.

I use the ChessBase GUI which is non-negotiable because of its stability and because it is easy use. I also use several databases, particularly the ICCF archive database. I also use the ChessBase MegaDatabase and the Playchess games database but ONLY for getting new ideas – human games are just too unreliable.

The Megadatabase - not all moves in there are correct but it
contains an enormous amount of ideas and inspiration.

I form opening trees in these databases but I do not rely on statistics. I analyse all variations carefully and only decide on my move after I’ve checked and prepared for all worst case scenarios. In CC you cannot rely on a “if he doesn’t see” strategy.

As much as my time allows I try to follow the latest in chess engine development. From what I’ve seen, the best engines of today are Komodo and Stockfish. Both have their virtues and ... well, almost no weaknesses. Stockfish calculates variations fast, and excels in tactics and attacking, while Komodo is solid in style, and its positional play is second to none. They are very close in strength continuously developed further. Both are an excellent choice for serious correspondence chess.

I have seen the latest ChessBase features such as Cloud, LiveBook and Let’s Check, and I find them exciting. They might be somewhat too “light” for elite correspondence chess players, but coupled with the amazing “Sampled Search” in Rajlich’s Fritz 15 they offer very exciting insights and help any chess player to enter the world of computer aided chess - highly recommendable for any OTB or casual CC player! In fact, I consider “Sampled Search” the biggest invention in computer chess ever.

Fritz 15...

To give you an idea how my approach to correspondence chess works in practice here is a crucial game from the final of the World Championship:

 
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As I said in the interview, opening preparation is extremely important part of modern correspondence chess. When reviewing the games of my opponent I saw that Zdenek after 1.e4 usually plays the Sicilian and here I did not find any weaknesses I thought I might be able to exploit. However, when checking his repertoire against 1.d4, I found one position/idea that had a significant probability a) to occur in the game and b) that could be exploited. 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.Bg5 h6 6.Bh4 The Anti-Moscow gambit is very often played in top correspondence chess; it leads to complicated and imbalanced positions that are ideal for lengthy analysis but which some engines still have difficulties to grasp. dxc4 7.e4 g5 8.Bg3 b5 One of the tabias of modern correspondence chess. 9.Be2 The most popular continuation. White has also tried 9.Ne5 a move that was introduced by GM Dhanish in 2006, but only became mainstream in 2009. It took some time before black found the way to equalize fully with Nbd7! 10.Nxc6 Qb6 11.d5 Bb7 12.a4 a6 13.Be2 Bxc6 14.dxc6 Qxc6 9.e5 Nd5 10.Nd2 Qa5! with interesting play, but black should be OK Another try that has been played in recent is 9.h4!? g4 10.Ne5 but here a final verdict has not been reached yet. 9...Bb7 10.0-0 Nbd7 11.Ne5 h5?! But several games (including this one) have turned players away from 11...h5. I guess that is what you might call fashion in correspondence chess. 11...Bg7 after which it was thought that Black could not hold: 12.Nxd7 Nxd7 13.Bd6 a6 14.a4 e5?! however, later games revealed a fine equalizing source for black: 14...b4! 15.Bxb4 Qb6 16.Ba3 Qxd4 15.Bg4 12.Nxd7 Qxd7 13.Qc1 13.Be5 is also quite playable. 13...Rg8 14.Rd1 h4? As will become clear a few moves later, this is a mistake - Black simply does not have time for this move. Several alternatives are feasible, most notably 14...Bb4 15.Qe3 Ng4 16.Bxg4 hxg4 and black lives to fight another day. 15.Be5 Qe7 16.h3 a6 17.b3! The key move that decides the fate of the game. After 17.Qe3?! g4 18.Bxf6 Qxf6 19.Bxg4 Bh6 Black created some activity. 17...Nd7 18.Bh2 b4 19.Na4 c3 20.a3 a5 21.Qc2! This was the position I had decided to go for and had hoped to achieve when playing my 1st move! I hadn't analyzed the full consequences of 21.Qc2 that early – that would have been a bit too much - but relied on a hunch or, to be more precise, positional considerations: It is painfully obvious at first glance that the white pieces are all active, while Black is extremely cramped. Moreover, the black king is still stuck in the middle and lacks breathing space. Rc8!N The best reply, although it probably does not save Black. But my opponent realized the problems of his position. With this move Black wants to avoid the exchange of rooks that might occur after a later axb4 axb4 is played. He wants to keep the rooks on the board to stop White's dark-squared bishop invading his position with lethal threats via b8-a7-c5. At the time when this game was played the chess engines did not spot this maneuver as it was buried deep in the so-called "quiescence search". Other tries are 21...g4!? and 21...Rg6?! but they give Black little hope to survive. 22.axb4 axb4 23.Nc5 Nxc5 24.dxc5 Qxc5 25.Qd3 Qe7 26.Ra7 After a series of forced moves White wins a bishop against two pawns. Rd8 27.Rxb7 Rxd3 28.Rxe7+ Bxe7 29.Bxd3 Bc5 30.Kf1 White must activate his king at any cost, otherwise Black's passed pawn will hold the draw. Engines are reluctant to play the text move and instead suggest something like 30.Ra1 However, monitoring the search process of the engines reveals that White's position does not get better the deeper the analysis by the engines goes. This is usually a sign that a different approach is required. 30...Ke7 31.Ke2 Ra8 32.Bc2 Ra2 33.Kd3! White activates his king even though it costs another pawn! Black's queenside pawns are a real menace (...c4 is a possibility White always has to reckon with) and White must mobilize all his forces. And White can only win (if he can win at all) if he plays on the white squares, gaining tempi and working with triangulations. To do that you need a piece that is able to make diagonal and horizontal/vertical moves. Therefore White's king holds the key to success. Bxf2 34.Be5 Ra5 35.Rf1 Rxe5 36.Rxf2 c5 From now on the position is very technical. However, I did not find a clear win but spent many sleepless nights looking for one. For a human finding a clear win in this position is almost impossible - but it here where engines excel: in ruthless calculation and move by move it slowly became became apparent that Black runs out of options. 37.Kc4 f6 38.Rf1 Kf7 39.Kb5 Ke7 40.Rf2 Kf7 41.Rf3 Ke7 42.Rf1 f5 43.exf5 exf5 44.Bxf5 Kd6 45.Kc4 Rd5 46.Bg4 Rd4+ 47.Kb5 Rd5 48.Re1 Re5 49.Rd1+ Rd5 50.Rf1 Re5 51.Bf3 Ke7 52.Rd1 Ke6 53.Bg4+ Kf7 54.Bh5+ Ke7 55.Bg6 g4 Black finally runs out of space and moves. 56.hxg4 Re2 57.Rg1 Kd6 58.Bd3 Re3 If I had Black in this position I would have resigned earlier. My opponent, however, played to the bitter end, which is rather unnecessary to say the least - particularly if you keep in mind we now have access to 7-piece endgame tablebases. Now, the game dragged on for another year. 59.Rd1 Ke5 60.Kxc5 c2 61.Bxc2 Rc3+ 62.Kxb4 Rxc2 63.Rh1 Rd2 64.Rxh4 The Lomonosov tablebases reveal that White in this position will mate in 34 moves if both sides play the optimal moves. Rd4+ 65.Kc3 Re4 66.b4 Kd5 67.Rh5+ Kc6 68.b5+ Kb6 69.g5 Rg4 70.Kd3 Kxb5 71.Ke3 Rxg2 72.Ke4 Kc6 73.Ke5 Kd7 74.Kf6 Rf2+ 75.Kg7 Rg2 76.g6 Ke6 77.Rh1 Rg4 78.Re1+ Kd6 79.Kf7 Rf4+ 80.Kg8 Rg4 81.g7 Rg3 82.Rh1 Ke6 83.Rh7 Ke7 84.Kh8 Ke6 85.g8Q+ Rxg8+ 86.Kxg8 Kd5 87.Rh5+ Kd4 88.Kf7 A crucial victory against a strong opponent who essentially did not make a single mistake - apart from 14...h4?, a move which theory at that time considered to be okay. 1–0
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WhiteEloWBlackEloBResYearECOEventRnd
Ljubicic,L2604Straka,Z25471–02013D43WCFIN28

(Part 2 will follow soon)

 


Martin Fischer, born 1962, is a ChessBase staffer who, among other things, organizes and holds seminars throughout Europe and helps administer playchess.com.

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