by Steve Lopez

Now that you're well on your way to becoming a specialist in your new opening, there are a few more ChessBase tools that you should know about.

The first of these is the piece probability table. This is one of the coolest features of ChessBase and probably the most misunderstood. What this function does is show you in a graphic way how often a given piece is moved to a particular square. The higher and thicker the green block is, the more often that piece was moved to that square.

The trick to using this feature is to run it on a limited number of games. I'll give you an example. Let's say you castled Kingside in a particular variation and got clobbered by a pawnstorm. It would seem that Kingside castling would be a bad idea in this particular variation. To find out, first save your game in ChessBase. In the "Databases" window, click once on your opening database (the one we've been working with these past few weeks). Bring your game back up on top and click "Opening classification" in the "Game" menu. This will bring up all the games that use the same variation as the game you got clobbered in. Double-click on the two dots at the top of the game list. This will kick you up to the next higher level of opening keys, with the variation of your game highlighted.

Next, click on the "push pin" icon at the bottom of the screen. This will take all the games of that key and put them on the Clipboard. Your next step is to close the "Key" window and open up the Clipboard. At the bottom of the Clipboard window, click the Statistics icon. In CBWin, this looks like a bar graph. In CB6, this resembles a colorful assortment of graphs.

A window will appear; its header will be "Statistics". Click the round button next to "Piece Probability" and make the range of moves "1" and "15". Click the box next to weighted so that there is no "X" in it. Then click the "OK" button. After a second or two, a chessboard will appear with green blocks on various squares. You'll also see (in CBWin 1.11 and later versions) a small chessboard in the upper right corner; this board shows you the square each piece spent the greatest amount of time on during the span of moves you specified (in this case moves one through fifteen).

In our hypothetical example, the one in which a Kingside pawnstorm wipes out your castled position, you'll want to look at piece placement for the White King. Click on the icon for the White King. Suddenly it becomes clear: the green block on c1 is larger than that on g1, ergo White castles Queenside much more frequently than he does Kingside. This may explain why you're frequently getting crushed after castling Kingside in this particular variation.

If you want more specific information, you could copy the games from the Clipboard into a temporary database. You would then do a maneuver search for games in which White castled Kingside and then run the standard "statistics" function on them (click the "statistics" icon and choose "Game information" instead of "Piece probability"). You'll get a listing of percentages for White wins, Black wins, and draws, as well as a "pie chart" showing the same information in a graphic format. Make a note of the percentage of Black wins when White castles Kingside. Now run a maneuver search for games in which White castles Queenside and run the statistics function again, making a note of the number of Black wins. A comparison of the two percentages should verify or disprove the thesis that White gets clocked when he castles Kingside in this particular variation.

Just for laughs, we'll try the same piece placement search on the White King, but this time we'll put an "X" in the box next to "weighted". What this will do is show you on what squares the piece was placed, weighted according to how much time a piece spent on the squares in question.

Look at the result:

We see that the White King actually spent the most time from moves one through fifteen on its home square of e1 than it did on either castled square, which is to be expected since we're dealing with the opening of the game (moves one through fifteen).

So you should be able to see the utility of this function very easily. If you play a game in a particular variation and wonder later if, say, your light-squared Bishop was placed properly, you can load the games of the variation onto the Clipboard, run the piece probability function, look at the placement of the light-squared Bishop and compare what you did to the play of masters and grandmasters.

Note, too, that this feature isn't only limited to the opening. You can search for middlegame piece placement as well, simply by changing the range of moves that the program references.

A related function exists in CB6 that allows you to view a piece's path during the game. For example, as I play through a game in my chosen variation, I can click on a King move and hit the "&" (ampersand) key to produce a graphic that looks like this:

Here I can see that the King didn't castle at all in this game. Instead it moved from e1 to f1 and from there to g2. If I want to make this graphic a permanent part of the game in ChessBase, I can just click the icon that looks like a diamond (at the bottom of the game window) and then select "Piece path" from the menu that appears.

Once you've started to notice certain themes occuring in your chosen opening, you may decide that it would be handy to have an index of all the games in which a given theme appears. You're in luck here, too, because ChessBase gives you the ability to create precisely this kind of theme index (or "key", as it's called in ChessBase).

Anything you can search for in the Search Mask can be defined as a theme in the theme keys. Let's take as an example the same idea we were just looking at -- that of castling. Let's say that I'd like to make a pair of indexes for my Scotch database, games in which White castled Kingside and games in which he castled Queenside.

The first step is to open up one of the theme keys. I do this by highlighting my Scotch database in the "Databases" window and then clicking the icon that looks like a blue key with a number "2" next to it. This allows you to access your secondary, or theme, keys.

A "Key choice" window appears, giving me a range of keys from which to select. The ChessBase manual suggests that maneuvers be classified under "Strategy", so I click on that button. A window (headed "Strategy (Scotch)") appears; in that window are the words "Key is empty".

Now comes the fun part where we actually create a key entry (a classification). Hit the [Insert] key on your keyboard. The familiar search mask appears. But it has a different function here; instead of searching for games, it will allow us to create an entry for our theme key.

Let's say you want to create an entry for White Kingside castling. In the search mask, you would click on the "Manoeuvres" button. Just follow the procedure for setting up a maneuver search. In this case, you'd place a "K" (for King) and "e1g1" in the proper boxes and then click the dot next to "W" (to designte "White"). You'd also change the "length" entry to "1". You might also change the entry for "Last" to a lower number like "20" and the "First" entry to a "4" (since Kingside castling is theoretically possible as soon as the fourth move). When you're finished, we just click the "OK" button. Back to the search mask you go, and you'll click "OK" there as well.

A narrow litle window appears, showing you your search criteria. This is your chance to change the listing to something a bit more meaningful then "WKe1g1". In this case, you might type something like "White castles Kingside". Then you click the "OK" button. Now you'll see your new theme classification appear in the key window.

Go ahead and create as many keys as you want. You can even make subkeys by clicking on a key to go to the next level down and add a key at that point. For example, you could click on "White castles Kingside" and, after the screen changes, add a new key for "Garry Kasparov as White". This subkey would show you all the games of Garry Kasparov as White in which he castled Kingside between moves 4 and 20.

Next you need to classify the games, sorting them into the keys. Go to the "Technical" menu in CB6 and click "Theme classification". In the submenu that appears, click on the type of theme key that you've been working with. To go back to our example, we'd click on "Strategy". A box appears asking you where in the database the classification should start. Type "1" in the box and click "OK" to let 'er rip! It'll take anywhere from a few seconds to a few minutes to classify the games, depending on the speed of your computer, the size of your database, and the number of keys you've created.

Once it's done, you can always click on the "blue key" icon to go to your theme keys and look up games by themes that you've specified.

Next week, it's back to the books (the paper kind). Until then, have fun!

I'm very interested in reading your opinion of this (or any other) issue of ElectronicT-Notes, as well as my book Battle Royale. I invite you to post comments to our ChessBase Users Group or else you can e-mail me directly.