Author: Komputer Korner
Date: 10:42:00 05/23/05
I finally figured out the real story behind retro moves and unplayed
transpositions in the Chessbase tree. Chessbase help does not explain the
following. You have to have retro moves,unplayed transpositions, and Show ELO
numbers checked on to follow the discussion below.You do this by right clicking
the Openings Book window. I don't bother to check on the Statistics option as
that only produces a graph which I don't need. However the first 3 options give
me valuable info. But you have to know how Chessbase presents the info.
Once you are looking at a position in the openings book window
with a book loaded such as Power2004 sold by Chessbase, you will notice that the
retro moves may have statistics beside them. Here we are only concerned with the
stats of %, Average , and Performance. They represent the previous ply (the
uninitated can substitute half move here) stats but now you are looking at the
stats from the opposite colour to the previous ply. Thus the stats are changed
to reflect the opposite player. The only stat that doesn't change is the N which
is the number of games that the stats are based on before the lines got pruned.
What confused me at first is that could add a move to the tree
and then the next window would show the retro move that you just added and
also the above stats but now from the point of view of the present colour. That
wasn't the reason why I thought there was a bug.The reason was that sometimes
there would be Number of games N associated with this move that was different
from the N which showed up in the previous ply opening book screens. I initially
thought that was because of transpositions in the tree. But it not only is
because of transpositions, but also because of unplayed transpositions.
Knowing this now, everything makes sense, however it sure is
confusing at first to get statistics from moves that have never been played
especially when these statistics are attached to retro moves that have never
been played. A word of caution, if you click on one of these retro moves that
has never been played, you will lose all the game score and all the opening
book moves line. To get the opening book line back you will have to start a new
game or reclick on the game in the database window if you had loaded it by that
route. I will do some further thinking of how the tree stats regarding retro
moves and unplayed transpositions could be done differently to make it less
confusing for the average tree user. I should also caution that except for the
1st few moves of a game, % stats are useless because of one blockbuster move
ruining a line of play or one bad move being replyed with another bad move.
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