Rybka 4 Book by Jiri Dufek
The Rybka4 opening book is a high-class compilation of opening theory. It was
developed for the world‘s strongest chess entity – a 100-core cluster
running the program Rybka4, used to maximize the program‘s playing strength.
The choice of variations in the openings book is well suited to the style of
the program, and the book has been fine-tuned and checked in thousands of games.
The Rybka4 Book includes 17 million positions and over 700,000 games, which
were selected from following sources: top human events, correspondence chess
games and computer chess games (up to April 2010). And this is only the starting
point: the value of the book lies in over 700 original analyses and move choices,
which lead to a re-evaluation in many critical points of modern theory. This
makes it useful for tournament and correspondence players alike.
The book contains a lot of computer checked analysis never published anywhere
before. The author of the Rybka4 book is Jiri Dufek (national master, FIDE 2276,
ICCF IM 2579), one of the world‘s leading experts in chess opening theory.
Jiri Dufek has been on the Rybka team since summer 2009, and after this date
his preparation was used in all official events which Rykba won. During World
Championship match between Vishy Anand and Veselin Topalov Jiri worked as second
of Veselin Topalov. In his long chess career he won twice Czech Correspondence
Team Chess Championship and wrote together with Roman Chytilek book Beating
the French Defence (in Czech only).
Interview with Jiri Dufek
Iweta Rajlich: How did your story with chess begin?
Yiri Dufek: When I was six my grandfather taught me how to
move the pieces. He was a relatively strong player, I think about 2000 in his
old age. However, he never reached the national candidate master title. A year
after learning the game I started to play in a local children’s club,
and my first trainer was Rudolf Soukal. However he was very busy at the time,
and I interrupted my training session for two years. At ten I joined the best
local club, Spartak Usti n.L., for a couple of years. At the age of 18 I was
rated only 2024, however two years later I made a jump to 2266 and stayed there
for a long time. At the same time (in 1992) I started to play correspondence
chess, as a member of the "B" team of my city. My first experience
was bad, but during the next season I played much better and then got an offer
to play in the "A" team. With this team I won the national team championship
twice and made one third place.
During this period I met IM Roman Chytilek and we started a long-term cooperation.
Together we wrote a two-part book called Bijte francouzskou! (Beating
the French), which is now available for download on my webpage, however only
in Czech. Our latest success was to win
the 4th PAL/CSS Freestyle tournament on Playchess. Lately I stopped play
OTB chess and started spend time into analyzing openings and interesting ideas
in general. In summer 2009 I got an offer from Vasik Rajlich to prepare a book
for the Rybka cluster, and later to prepare the book for the new Rybka. This
offer started our cooperation, which led to one peak of winning the MundialChess
Freestyle tournament, using his 108 cores cluster during this tournament. At
the moment the latest milestone in my chess career was to be the second of Veselin
Topalov in his World Championship match against Vishy Anand.
How long have you been making opening books? Can it be a profession?
What is so cool in openings anyway?
I took my first steps while testing on Playchess a few years ago, but I could
hardly call this making a book. I started to prepare a real book for the Rybka
cluster during the summer 2009. It is really interesting to analyze unknown
positions and ideas from chess books, chess practice or computer games, and
to find your own solution. However it is not possible to do this every day for
eight hours. Today's chess preparation of players is very deep – it is
not surprising that in some games players lose in the middlegame because the
opponents simply know the lines for dozens of moves, from the opening to the
endgame. This is even worse in computer games: long lines, very often 50 moves
long, lead to draws that are similar to prearranged human draws.
Is it fun for you when you are making opening preparation for the Rybka
Yes, in some ways, but it is hard work too. The first important thing is a
good choice of games, because is not possible to make wide books purely by hand.
The second thing is to choose the "right" openings – a narrow
book can perhaps score pretty well for a short period, but I wanted to add much
more information value. This is why I added human openings for the non-tournament
book. The third thing is the testing phase, which works in cycles – testing,
finding weak points, analyzing and improving bad lines, updating the book, new
testing... During this period I used Aquarium 2004 and Chessbase 10 for making
How much time does one take to make a decent opening book?
A lot of time. Finding the right games and generating the book is the work
of a few hours. Toying with priorities is a very time consuming task –
it took a number of weeks. Testing games is an independent process, but only
checking of results, finding lines which need corrections, that is the work
for a few days. Last but not least is the phase of finding new ideas and understanding
why the engine plays badly in very good positions, from my human point of view.
This phase is not only very time consuming, but needs a lot of invention and
Do you have a very special, private book for tournaments?
Yes, but for Rybka 4 I moved my priorities away from the tournament book which
I used with the Rybka cluster. Generally I can say that the Rybka4 Book includes
maybe 95% from the book which I used during tournaments, plus a lot of new material
– analysis, up-to-date games, etc.
For whom is this new book made?
I want to say for everyone, however I am not sure that this is really true.
There are three groups. First the chess engine fans. They will find up-to-date
information about their openings. The second group would be everyone who wants
something new, new ideas or new setups. And last but not least the book is for
chess players, as a highly topical chess guide.
No, I didn't. From my experience, GMs are not so interested in this computer
engine stuff, but if there is any feedback I will be happy, and it could be
useful for future work.
As far as I know, you were the only new member of the Topalov team in
his match against Anand. How did that happen?
During my visit in Linares I met Veselin's seconds – Jan Smeets and
Erwin l'Ami. After my game with Veselin we spoke generally about chess, openings
engines and differences between human chess and the chess engine world. When
I returned home I got an offer from Silvio Danailov to join the team of Veselin
for his match against Vishy Anand.
I'm sure that Topalov's decision to add you to his team can in a large
part be attributed to your expert opening knowledge. Do you feel that you
are contributing to the team in other ways, for instance through your knowledge
of computers, advanced analysis methods, etc?
I think this question is more complicated than it looks at first sight. Firstly
Veselin (and GMs in general) have their own ideas on how to play openings. It
is totally different from engines matches. Nobody is interested in long lines
which can draw at end, because memorizing these lines is very difficult and
time-consuming, without any big chance for success. Secondly I very often checked
existing analysis and was looking for improvements or analysed lines which were
assessed as important for a match. We ended every time with the same conclusion
in our analysis. Thirdly I provided quite a successful IT support for the team.
Did you use ChessBase products while developing the book?
Yes, of course. I have used ChessBase products for years. I use ChessBase 10
as the main program for storing my analysis and for my work with databases.
I found very useful online access to database. The Fritz GUI I use for automatic
“Deep position analysis” – for analyzing positions and for
How would you describe your opening book? For example, is it a narrow
book, covering selected opening deeply, or is it a "wide" book containing
most openings that arise in practice?
Generally the book is relatively wide. I wanted to prepare two ways to play
every opening, but sometimes I used only one, because I thought that was best.
But the main repertoire is based with white on the Najdorf with 6.Be2/h3/Be3/Bg5,
Caro Kann with 3.e5, Ruy Lopez, French with 3.Nc3 and 3.e5, the Catalan, the
classical KID with 9.Ne1 and 10.Be3, the Exchange Grunfeld, Nimzo Indian with
4.f4, etc. For Black there is the Sicilian Kan (e6+a6), which the cluster proved
was very good in tournaments, the Sicilian Najdorf and Rauzer with Bd7, the
Caro Kann and Ruy Lopez (Berlin Wall and Jaenisch). After 1.d4 there is the
Grunfeld and a lot of Slav (Chebanenko 4...a6) and Semi-Slav stuff, same as
the Nimzo Indian, where I used my openings from the cluster book.
Which opening line did you spend most time on?
It's very hard to answer. Probably the most time consuming was the Najdorf,
but I am still not 100% sure about the truth in this opening. The most fun I
had was analysing the Jaenisch in the Ruy Lopez, because very often not every
best move of the engine is really the best. But that is not all. I added about
700 analyses of different openings into the book. They are not often set for
the tournament book, but mainly for wider use by the players. In other words
there are continuations of sidelines which have improved existing theory, or
recent games – look and you will see for yourself.
Can you show us a few interesting novelties from the book?
The second part of this interview with novelties and
new ideas from the Rybka4 book will appear in the next fews days.
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