by Steve Lopez

There are a few more opening book features we'll look at this week. In Fritz6, when you click on the Edit menu, you'll see the item "Openings Book". If the opening book you're using is located on a CD, most of these items will be in half-tone ("greyed out"). To make these items available, you'll need to have the opening book on your hard drive.

First, go to the notation pane on the screen (the place where Fritz displays the notation of the game currently loaded or in progress) and click the "Openings book" tab. Return to the Edit menu, select "Openings Book", and click "Copy tree to hard disk". The program will then display the Windows file select menu, in which you'll select a folder into which to save the opening book. Please take a little time and choose a folder carefully! In the event you decide to change to a different opening book and later want to get back to the original one, you'll need to know what folder this opening book is saved into. The default folder Fritz6 displays is fine as long as you remember it!

Once you've selected a folder, click the "Save" button and the opening book will be copied to your hard drive. The program will then switch to that book by itself (in other words, you won't have to load that book manually after the copying is completed -- it will already be loaded from the hard drive).

Be aware, too, that Fritz' opening book is 130 Mb in size, so make sure you have enough storage space on your hard drive before copying the tree to it.

Once you've copied the tree to your hard drive, the other options in Edit/Openings book become available to you (they're no longer displayed in half-tone). Since we're looking at beginning steps in using Fritz, we won't examine most of these (and several have been covered in past ETN issues anyway); we'll just consider the ones most useful to beginners.

Click on the command "Book options" and a new window will appear which give you several ways to alter how Fritz6 uses its opening book:

The first thing to consider are the check boxes in the upper left corner. Unchecking "use book" means that Fritz won't use its opening book at all when playing. In general, you'll want to leave this box checked. If you're having Fritz play against another engine from a known opening position (for testing purposes) or else having Fritz play from the same position several times in Shootout mode from a position several moves into the opening, you may want to consider unchecking this box (so that the opening book won't influence he outcome of the games or the programs' analyses).

The second box is marked "Tournament book". Although there are many variations in the standard opening book that accompanies the program, Fritz will not play certain lines that are marked as being bad for computers to play. However, these lines are still in the book so Fritz will know the proper responses in case its opponent plays these lines. Unchecking "Tournament book" means that Fritz will play these lines, despite the fact that the author of the opening book has instructed the program not to play them. This gives you, the human player, a wider range of responses from the program.

Another way to increase the range of responses is by using the "Variety of play" slider. This is pretty simple to understand. Slide it to the right to increase the variety of opening Fritz will play; slide it to the left to limit its responses to the "best" (in the opinion of the book's author, as well as in practical results from human vs. human play) openings.

Fritz will "learn" from its successes and failures; the more you play it (or have it play against other programs), the more practical "experience" it will gain. It will tend to favor openings it's been successful with while avoiding openings that haven't worked out too well from the program's standpoint. The "Influence of learn value" slider determines how much Fritz' past results come into play when it's deciding on an opening. The "Learning strength" slider determines how much each individual game affects Fritz' opening book. Sliding these to the left decreases the effect of past experience, while sliding them to the right makes these effects more pronounced and influential. To get the widest variety of play possible from the program, slide these over to the left.

"Minimum games" determines how often a position must show up as having been previouly played for Fritz to select it as an opening move. Setting this to a lower number means that Fritz will play a wider range of openings from its book, while setting it to a higher number means that Fritz will stick to the "main lines" that have been played over and over in master and GM practice.

There are also a number of buttons that are shortcuts to setting these various parameters. "Optimize" means that Fritz is set up to play from its tournament book and will learn from its games as they're played. This is the setting to use when having Fritz play in Rated Game mode or against other chess engines. "Handicap" turns off the tournament book. "Normal" returns the book to its "factory" settings.

Going back to the Edit/Openings book menu, you'll see an item that reads "Reset weights". If you're using Fritz' learning functions (as described above) Fritz will alter the "weighting" of different moves in its book on the basis of the experience the program has accumulated in actual play. To reset these weights to "factory" settings (that is, to the way they were when you first copied the tree to your hard drive), click "Reset weights".

Over the last two articles, we've looked at the basics of the opening tree in Fritz6. Prior to that, we considered the basics of database use. Now that we know a little about opening books and databases, we're ready to move on to the topic of how to use Fritz to analyze our own games. We'll start on that topic in next week's ETN. Until then, have fun!

You can e-mail me with your comments, suggestions, and analysis for Electronic T-Notes. If you love gambits and sacrificial play, stop by my Chess Kamikaze Home Page and the Yahoo Chess Kamikazes Club.