Practical relevance/opening repertoire

Now after the previous ideas and perfect opening lines, whereby black can maintain a draw, one can (and indeed should) ask what's the practical relevance in chess..

Well first of all, by using such almost perfect opening lines, an opening book for a chess program becomes much better of course. Much better ? Well, at least slightly better. For example i've tested my Arena book against the main book by H.Schapp, and achieved improvements of about 60 Elo points. Not really very much, and indeed, the engine/tactics still are much more important.

So what's the relevance of such opening theory for human players ? Well, having thought about this a bit more, i suspect that the approach of finding 'best' opening
moves is not really suitable for human players, having not such perfect memory as computers of course.

Yet another approach can be worthwile, namely choosing opening lines which restrict the number of playable options
for the opponent. Does this mean choosing the sharpest lines like gambits etc.?

Well, not necessarily, when playing e.g. a gambit like Kings Gambit, after 2. f4?! black still has a lot of playable options (ie. resulting in = lines) options,
and probably 2. Nf3 with such an approach still fundamentally is better.

Yet.. when looking at opening theory in such a (new?) way, other lines than 2.Nf3 also can be played, e.g
2. Nc3, or even 2.d4!? And in the latter case, after 2.exd4, white can also play interesting gambit lines
with eg. 3. c3 (Danish gambit) !

In such a way opening play is a bit similar as middle game play, in the sense that it is useful to gain
mobility of your pieces for your own side, whereas simultaneously trying to restrict mobility of
your opponent(s) pieces.. (i suspect many chess programs still are not very good in evaluating mobility,
especially not in end games, eg. when looking at positions like 'fortresses'and so on..).

Anyway, using such an approach (of trying to restrict nr of playable moves for the opponent, already
in the opening stage) of course the human player would benefit a lot of practical knowledge of the
variations he would choose, especially in sharp lines, such as the above mentioned Danish gambit.

So the practical relevance of this idea is that knowing opening theory, having a repertoire aiming for
above strategy, and using for such purposes a program like Bookbuilder, can be useful for the human chess
player in practical (otb) play !
(and yes, i've experienced this myself as well ofcourse; my standard rating on playchess.com now is more
than 1700, and still increasing..)

So, enough for the moment about computer chess, and back to the more interesting human chess again, i would say.. :)