Questions about my opening book?

[ChessAddict]

When creating my opening book i noticed that it only plays out to thirteen moves? Is there a reason why it only played that many moves and is there a way to change it? Thanks.

[Eelco de Groot]

When creating my opening book i noticed that it only plays out to thirteen moves? Is there a reason why it only played that many moves and is there a way to change it? Thanks.

Hello Arnold,

I think it is difficult to give specific advice if you do not provide more details in what GUI you are working, or with what standard. For every opening book you make there are parameters controlling the length of the variations that are put in it. This is done so you can make very detailed or very short books just for your own purposes. You probably made something with the default parameters.

There is a lot of material on making opening books, here some recent posts made on the Rybka forum so you have a place to start:

http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=3646

By Mark Mason Date 2008-04-14 07:08
Actually you'll find that the advice given above, together with other useful advice on book making, are a direct lift from the excellent enginechess.com site so probably best to go to that site and bookmark it:

http://www.enginechess.com/bookmakinghints.htm

Also excellent advice is given at Kevin Frayer's site under "bookmaking Q&A"

http://www.frayerchess.com/


Mark

http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=3752

Regards, Eelco

[ChessAddict]

Well i'm using the Shredder GUI. I wanted to ask does maybe have to do with choosing "relative length" or "absolute length" for how many moves into the book? Thanks.

[Eelco de Groot]

Well i'm using the Shredder GUI. I wanted to ask does maybe have to do with choosing "relative length" or "absolute length" for how many moves into the book? Thanks.

Yes, that is right! It is in Shredder's Help function but you have to look through various items to get a better picture of all the bookoptions, it says in Opening Books -> Import

Import games

You can import databases in CBF and PGN format in an existing opening book of Shredder.

These are the options:



With import lines the side lines of the games will also be imported in the opening book

Import statistics updates the statistics in the book according to the results of the imported games

Import move attributes imports move comments in the book

The length of the imported games can be set either in absolute plies or in plies after the last found position in Shredder's internal ECO database.

I believe in Chessbase manual they recommend to choose the second option, a length after last position classified under ECO, but if you want to tailor an opening book for a chessprogram it is important the lines should end with a position that the program knows how to play on its own, if it doesn't you can try to improve the results by adding more and more moves in theory, but there is a limit to that in practice I suppose. But short answer, you were right about the place where you can change the length of the book variations!

Eelco

[ChessAddict]

Do you know which of the two, relative or absolute length, would give me the longest possible moves out of book?

[Mark Mason]

Arnold,

These comments appliy to ctg book format made in Chessbase GUI:
If you choose ECO Relative it restricts the number of moves in each line relative to the ECO classification. This results in long variations for theoretical main lines (ECO classification position found late in the game) and short variations for side lines (i.e., early deviations).

If you choose Absolute then the book will be created with your specified number of moves in every variation - regardless of how common or unusual the line is. Therefore choosing Absolute will give you the longest lines out of book and the deepest book, and also the largest size of file.

By the way when you choose the number of moves to make your book with bear in mind it is plies or half moves not full moves. So if you want your book to play to 50 moves deep then compile it with Absolute 100 (100 half moves = 50 moves). However when loading your book to actually play in the Chessbase GUI (either on or offline) , then the number of moves in book options is actually the true number of moves so in this example, you would set 50.

It is suprising how many people don't realise this and it can be confusing so thought I'd clarify in case it helps.

Mark

[ChessAddict]

Okay, thanks for the information. You answered my question!!