POWERBOOK 2005 on DVD
The Fritz Powerbook 2005 is an openings book and
database that will run with Fritz or any Fritz compatible engine (Shredder,
Junior, Tiger, Nimzo, etc.). You can also use it in ChessBase 7, 8 or 9 to
conduct openings training and hone your repertoire.
The Fritz Powerbook 2005 contains 20 million
openings positions, which were derived from 1 Million high-class tournament
games. Together with each position all relevant information is stored: all moves
that were played in the position, by players of what average rating, with what
success and performance results. The games from which the Fritz Powerbook 2005
was derived are also included on the CD. This means that in any position of the
opening tree, you can load and replay the games in which the position occurred.
The Fritz Powerbook 2005 represents the state of
the art of current opening theory. It can be used to discover exciting new lines
(e.g. never before played transpositions) and practice them against Fritz.
Fritz 8, Fritz 7, Fritz 6 and all other ChessBase
engines under the Fritz interface can use the PowerBook 2005 as opening book,
making the opening play of the programs more topical, versatile and
Review by Steve
What is an openings book?
In the initial phase of a game, the program plays
out of an “openings book”. This can consist of millions of openings positions,
and for each of these, the program has full information on which moves were
played, how often and with what results. The program stores its own experience
with openings variations it has played. It learns from success and defeat.
The openings book is called the “tree” as
the branching variations in the opening resemble the structure of a tree. The
files that make up a tree are pretty large. The program requires about 80 bytes
to store a position and all the information associated with it. You can leave
the files on the program CD. However, in this case, the program will not be able
to modify the book as it plays games (i.e., it cannot learn). Thus, it is
advisable to copy them to your hard disk.
Some things to note:
- The size of the openings tree is limited only by the amount of disk
space available. It is important to note that access to the information is
always extremely fast, even if the files are truly gigantic.
- Existing openings trees can be easily extended, simply by importing
games. This means that whenever a series of high quality games are
available, the program can read them and extend its openings knowledge.
- The tree recognises all transpositions, even those that did not occur in
the games from which the tree was generated. Sometimes you may be able to
switch from one known position to another with a move that has never yet
- The tree can handle reversed colours perfectly. For instance after 1.d3
d5 2.d4, the program is likely to reply 2...c5! and play the entire Queen’s
Gambit as Black.
- The openings tree is not just an instrument to make the program strong,
it is also a very powerful training tool for chess players. For this reason
each move can be marked with chess symbols like “!” and “+=“.
Using the book window
In Fritz and ChessBase you consult the openings
book by clicking on the “Openings book” tab at the top of the notation window.
This is what you see in the openings book tree:
- <Moves: (below tree icon) Sometimes a
move will appear in grey, which means that it was never played, but leads to
a position that results from some other line.
- Number of games: (N) The header
displays the total number of games which led to the current board position.
The N column displays the number of games in which each move was executed.
- %: Percentage score achieved by the
move, always from the point of view of the colour to play. If the number of
games is low, the percentage is given in grey because it does not have great
- Av: Elo average of the players of the
move. If only a small percentage of the players had a rating, then the
number is given in grey.
- Perf : Elo performance of the move. This is the rating a player
would have achieved in a fictitious tournament, playing the move in all his
- Weights:The weights allocated to each move control the
probability with which it will choose the move in a game. The value can
range between –125 To +125. The values are initially set to zero, but may
change when the program actually plays games in the individual variations.
You could say that the program is learning from experience. The weights can
be manually modified by right-clicking a move and selecting “Change weight”.
If you reset all weights the program will use only the purely statistical
information to select its moves.
- Prob and [%]:The first value is the purely statistical
probability of the move, based on the number of times it was played and the
results achieved in the games that went into the book. This is the
probability of the move being played by the program as long as the weights
have not been changed – either manually or by automatic learning. The value
on the right [%] is the practical probability of the program playing the
move. This is a product of the statistical evaluation and the weights. If
you change the latter you can see how the [%] value (but not the “Prob”)
changes. In Book options you can determine how much the weights influence
the probability of play.
Right-click the book window to configure the display, i.e. enable or disable
a number of elements of the tree window. These are the most interesting:
transpositions are moves that were not actually played in the games,
which were merged into the tree, but which lead to another known position.
This is a treasure trove for interesting moves which can come as a nasty
surprise for your next opponent.
- Retro movesare
the moves leading to this position from other positions in the trees.
displays exact details for each move as a bar graphic at the bottom of the
screen (as in the picture above). It shows in how many games the move
occurred and what percentage of these games were won, drawn or lost. The
graphics make it easy to take in the information at a glance.
||Unplayed transpositions, retro moves
The moves in grey
(8...h6 and 8...Nc6) have never been played in the current position, but
lead to positions that are part of openings theory.
8.0-0 and 8.Bd3-e2
are moves that lead to the current position.
How to navigate the
- Use the up/down cursor keys to move the headlight bar up and down.
- Use the right/left keys to move forward and backwards in the variations.
- Click a move with the mouse to move forwards in a variation.
- Right-click a move to annotate it.
- In the same menu you can exclude a move from tournament games. The move
appears in red. Repeat the action to make it playable again.
Right-click the book window to execute a number of commands, e.g.:
- retrieve the
game in which the curren position occurred;
- sort the moves
- prune or delete the tree
||Right-click a move to
- annotate it (with !, ?, +–, etc.);
- make it the main move in the current position;
- instruct Fritz never to play this in tournament mode;
- modifiy the weighting manually;
- delete the move or variation
In Fritz you click Edit
– Openings book – Copy tree to hard disk. This will copy an openings tree
from the CD to your hard disk, making access faster. Doing this also allows the
program to learn from the games it has played and by reading databases.
Importing games to the
Click Edit – Openings
book – Import games. This very powerful function allows you to extend the
openings book very quickly and with no technical hassle. You can, for instance,
import all the games of the latest ChessBase Magazine, or only those from the
lines you play. The games will be merged to a tree of positions. The length of
the variations ist limited in two different ways: You can specify that every
variation should be “n” moves long; or, more sensiblly, you can limit the
variations relative to the ECO classification. This results in long variations
for theoretical main lines (ECO classification position found late in the game)
and short variations for side lines (i.e., early deviations).