Game Spotlight: The Problem With Opening Books

As the world temporarily pulls away from public events, it’s a fine time to study to improve your Chess.  As part of this, you may want to learn a new opening, or improve your understanding of the openings you play.  Which means you may want to read some opening books.

While there are certainly some excellent opening books out there, I should point out that even the best suffer from an invisible bias.  This is easiest to explain with an example.  Here’s a position that appears in (at least) two opening books about the Pirc Defence:

I’ll put off looking at why all these moves happened for later.  For now, it’s enough to say this is a very sharp tactical line, where both sides may have some options, but playing outside those likely means disaster.  The point is to look at what the opening books write about this position.  James Vigus writes about Black’s last move, “Again, the only move, preventing Nc7+ and ensuring that after the white knight has captured the bishop on g7, it will not emerge alive,” in The Pirc in Black and White.  Vigus also lists this as the main line following from White’s 8th move, e6.  Lev Alburt and Alex Chernin’s Pirc Alert goes farther, stating, “A critical moment in the Austrian Attack: 12. …cxd4!, 13. Nxe6 Qc4!! and Black has a good game.”  They go further later on, calling White’s 12th move Qxg4, “A critical moment for Black in the whole history of the Austrian attack!” and writing about Black’s 13. …Qc4, “After this beautiful move, discovered by several different grandmasters simultaneously, Black’s game again blossoms.”  So, this looks like a very important line to study if you’re going to play either side of the Austrian Attack in the Pirc Defence.

You’d expect after reading that this would be backed up by a wealth of evidence.  Let’s look at that line again, except I’ll add in a couple of extra notes.  First, I’ll put in common alternate moves where they occur.  Second, I’ll add some numbers as comments.  These are the numbers of games played using those moves, according to the database at a bit before 2020 began:

Not so important now, is it!  Even worse, less than a handful of those games involve players rated under 2200!

There are a few reasons for this, to be fair to the authors here.  One is that databases cover a large time period, and if moves were discovered fairly recently they won’t show up as much in practice.  (Although the earlier of the two, Pirc Alert, was first published in 2001, so I’d have expected this move to show up more in almost two decades.)  Another is that if a move is particularly bad for one side and is known to be such, players will simply avoid it.

The more important point, though, is that opening books simply do not consider how likely a position is to appear on the board.  That’s a problem when you’re trying to figure out where to spend your time studying.  You only have so much time, so you need to be concerned with the practical, not the theoretical.  Check your lines against an opening database to see how important they really are to study, and stick to the more important ones first (unless you know for certain someone you’re likely to play against likes playing something less mainstream).  Using your time wisely is more likely to lead to success.

Since we’re already looking at it, here’s one of the games in this line involving an under-2200 player:

We’ll continue to offer tournaments online using our club as the COVID-19 pandemic continues.  We’ve started two team tournaments in the past week, as well as a thematic tournament in the Caro-Kann Defence.  (Though it’s worth checking — these may still be looking for a few players as this article publishes.)  It’s best to be signed up to the club to get information about new tournaments quickly.  Otherwise, the World Health Organization continues to update their page on the pandemic frequently, so that’s the best place to go to find best practices to keep yourself and those around you safe.

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