Backsolving

This  example compares what you can learn about chess openings from a game database (with tree features such as ChessBase and Chess Assistant) to what you can learn with a positional database (Chess Openings Wizard) that contains the exact same information.

Backsolving is one of the most sophisticated features of Chess Openings Wizard – and one of the least understood. This article takes a bit of the mystery out of this feature by showing how it works compared to statistics.

Suppose you have a huge game database.

You search for your favorite White opening and find 97 grandmaster games with 12.Ng5.

Games White Wins Draws Black Wins
12.Ng5 97 51.5% 31.0% 17.5%
12.Bd2 61 34.3% 32.7% 32.7%
12.h3 3 33.3% 33.3% 33.3%

The game tree tells you that about 51% of the games were won by White, 31% were drawn and 17% were won by Black.

Because you play the White side, the move 12.Ng5 starts to look very attractive…

But wait – you view some of those games and find that grandmasters have been playing 12.Bd2 for the past three years instead of 12.Ng5, even though 12.Bd2 shows only a 34% winning percentage for White.

What’s going on?

You then look further into the games and find that in just two key games Black has found a way to completely neutralize 12.Ng5 – and even get a slight advantage!

Naturally after those games were published, grandmasters gave up on Ng5 for White.

So the game tree statistics would have lured you into a bad position.

Backsolving does this research for you and makes it obvious when game statistics and current chess theory contradict each other. Here’s what the candidates might look like after importing those grandmaster games into Chess Openings Wizard Professional and then backsolving:

The backsolving process was able to show that with best play by both sides, Black could achieve a slight advantage if White plays Ng5.

Backsolving

This book was also analyzed by a playing program and the score of -131 means the computer engine agreed with this assessment. Down the 12.Ng5 line it is now easy to see the Black moves that keep the edge.

Automatic solving is easy; simply change the assessment of the last position in any line (a ‘leaf node’) and press the rewind button. As the moves are taken back, each position is re-evaluated. Chess Openings Wizard Professional supports two assessment symbols, one for the opinion of the author and the other for the results of Backsolving.

Backsolving also works with computer evaluations. Combined with overnight analysis, this allows you to create a theory machine that points out flaws in your repertoire – and discovers new improved lines.

Backsolving can also show you where the bulk of the positions are in the tree of analysis. Looking at the candidates, 202 positions are recorded beyond 12.Ng5 while only 17 positions are stored after 12.h3. Of course, even though more analysis appears after 12.Ng5, it is no longer the main line – White would rather play a move that leads to an unclear or equal position.

It is precisely because 12.Ng5 is refuted and is no longer being played that game statistics for that move are likely to stay the same in the future.

Thus a bad move will continue to look attractive (statistically) in a game database long after it has been refuted.

Backsolving is a feature unique to Chess Openings Wizard Professional, one of many power tools that make it the premiere software for studying chess openings.

Did we enlighten you? Confuse you? Email us with your comments. Thanks!