Computer Chess Club Archives


Search

Terms

Messages

Subject: The Mirage of backsolving

Author: Komputer Korner

Date: 18:45:48 05/17/05


It is incredible that once a dishonest or false idea takes hold in the
marketplace, how very difficult it is to overturn it. Once it becomes a sacred
cow, most people just accept it on faith. Thus unfortunately is the case with
backsolving. Let us suppose that you have either bought, inherited or downloaded
an electronic openings book without any annotations. How are you going to know
what lines will be in your repertoire/ After soul searching and examining lots
of the opening lines, and other advice, you decide to play lines that fit your
style. However within these lines there are many options at each move node. Let
us say that you have one important position with 4 move choices at the 4th move.
How are you going to get these multi move choices annotated so that you will
know which lines to memorize for (over the board) or which lines to play for
internet or correspondence chess. If you can't afford GM or IM analysis of your
repertoire and don't trust your own analysis, you are left with either having an
engine analyze the opening nodes or you backsolve. If you backsolve you are
forced to put in a lot of extra move lines because backsolving depends on an
ending result or an evaluation far up the tree(deep into the game). So if you
are a committed backsolver, you accept this and you search for a lot of GM games
in your specialty opening repertoire to add to your opening book. You will have
to add an evaluation to the end of each one of these lines and then you
backsolve. However,  there is an average of 3 positions in every GM game where
the assessment of the game is overturned (in other words, the assessment goes
from advantage from one side to the other or an equal position goes into an
advantage to one side or Vice Versa). This means that you are never sure that
the result really represents the value of the opening node  line that you want
to have annotated and that backsolving indeed gives you as it backs up the
result evaluation to the opening node position.  So you cheat a bit; you don't
put the complete GM games. You put in the 1st 30 moves or so and then have an
engine evaluate the final positions after 30 moves or wherever the engines give
a definite advantage to one side and then backsolve again. There is a separate
problem with equal and unclear positions but more on that later. However, you
wasted engine midnight analysis sessions on the 30th move analysis which you
probably will never get to play as your opponent will have veered off on another
line far sooner. The point is that backsolving is doing its annotation work (on
positions that you have your engine analyze) far up the tree (beyond the 30th
move) on positions that you will never encounter. Even if you back that up and
only analyze positions after the 20th move and then backsolve you will still
never encounter those positions in a real game. Opening study really means
opening study. It doesn't mean ending study. It doesn't mean mid game study. Of
course you should do some of those as well but only after you have a solid
repertoire. You are far better off putting your engines to work on that 4th move
(in other words study openings the old fashioned way).   Now for the unclear
lines that the backsolvers 30th move analysis showed that I promised to talk
about earlier. These lines represent a special problem. If you backsolve them,
then you haven't really accomplished anything because the opening node that is
the ultimate target of your backsolving has your 4 opening  choices without any
annotations before you started backsolving. Having no annotations is really the
fact that you don't know what is going on therefore  they are unclear.   So let
us say that 2 of the lines are backsolved to be unclear and one line was large
advantage for one side and the other line was backsolved to be equal. So the
only one we haven't talked about is the equal line.  It has the same problem as
the unclear line. Since most games have 3 position overturns as explained above
you are not really sure whether the line was always equal from the 4th move on
or else it became an advantage and then was turned back into equality because of
mistakes. if every game was played perfectly, then backsolving would be worth
it. However that is not the case. So to sum up, put your effort into evaluating
opening positions and opening strategies and traps. There is no magic bullet
that will solve chess and backsolving doesn't solve anything.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.