Material searches in ChessBase 9 – part three

In the previous two ChessBase Workshop columns we looked at the basic operation of the Material Search dialogue in ChessBase 9. That stuff was pretty simple for the most part. In this column we're going to look at something much more difficult, made so because it involves math (ugh!). But we'll take it slow and easy and we should be able to get through it without anyone's brain becoming too scrambled.

First, though, we'll look at something easy which we've overlooked up to this point: the "Length" setting:

This is pretty straightforward -- it's simply a value for the number of moves the specified material balance must be on the board (before it changes through capture or promotion). The default setting is "2", but you can adjust this as you please.

Now comes the hard part: the "Total" and "Difference" toggles, which are located just below the "Ignore colors" box (which has already been explained in the two previous columns):

Just the words "Total" and "Difference" imply that numbers will be involved. Both of these boxes have something in common -- clicking one of them changes the basic way the Material Search dialogue works.

We'll start with the easier of the two: the "Total" box. In a lot of ways its function is similar to some of the other settings we've seen. Let's click on the "Total" box and see what it does to the Material Search dialogue:

The first thing we notice is that the values for the White pieces have all changed. This gives us a valuable clue as to how checking the "Total" box changes the functionality of the Material Search dialogue: selecting "Total" deactivates the numeric toggles for the Black pieces -- only the values for White are used. Why? Because clicking "Total" means that we're going to search for the total combined amount of material on the board (i.e. the number of specific White and Black pieces added together).

Let's look at an example. Say we change the numbers as displayed in the illustration below:

We've reset the Queen's values at "1" and "1". This means that the position can have no more than a single Queen on the board; one of the two players must have lost his Queen at some prior point. Looking at the Rook values, we see the values have been reset to "3" and "3" -- this means that there must be exactly three Rooks on the board, regardless of which player owns what quantity of Rooks. If we'd set the Rook values to "1" and "3" instead, it would mean that the position could have anywhere from one to three Rooks on the board: no less than one Rook and no more than three of them.

The remaining three piece toggles indicate that there can be zero to two total Bishops on the board regardless of color, zero to two Knights, and zero to sixteen pawns.

Clicking "OK" we'll get a list of games in which the total pieces for both players combined are as follows: one Queen, three Rooks, zero to two Knights, zero to two Bishops, and any (legal) number of pawns. A sample position from a search I conducted looks like this:

Making a quick count, we see that there's one Queen, three Rooks, two Bishops (the maximum we allowed), one Knight (which falls within our parameter of zero to two), and thirteen pawns (again within the range [0-16] we specified).

Note that when you do a "Total" search, the "Ignore colors" box doesn't matter -- we're doing a search for the total amount of material for both players added together, so color is irrelevant.

That's pretty simple once you know what the "Total" box does. But now we come to one a wee bit more difficult to get our heads around: the "Difference" box. Let's reset the Material Search dialogue, click the "Difference" box, and see what happens:

Yowza! All of the left hand values for the Black pieces now appear as negative numbers! This gives us a big clue, though, as to what the "Difference" box does: it allows us to specify that one side must be behind by a certain amount of material. Additionally, the "Difference" box allows the input of negative numbers in the Black piece value boxes.

Here's how it works. Let's say we want to find positions in which one player is down a pawn. First click "Any pieces", which will set all of the piece and pawn numbers to their normal ranges (zero to the normal number of that piece or pawn). Then click the "Difference" box, which will then cause the Black side of the dialogue to display negative numbers. Change the Black pawn values to read "-1" and "-1" (meaning that Black must be down a pawn):

Then click "OK" and you'll see a list of moves in which Black is behind by one pawn. Here's an example of a result -- clicking on a game that just happened to be a From Gambit showed me this board position:

This position arose after the moves 1.f4 e5 2.fxe5. And it certainly meets our requirements -- one player is down a pawn.

Now let's try for something different: one player sacrifices a Knight for two pawns. Here's the setup:

...in which Knight values are set to "-1" and pawn values are set to "2". And here's a sample position:

This is obviously a Cochrane Gambit in Petroff's Defense; White has taken the e5-pawn and sacked the Knight on f7 (taking a second pawn), while the Black King has recaptured on f7. So White has given up a Knight for two pawns, exactly the kind of thing we were looking for.

However you'll need to note that this particular search also brings up games in which a Knight has indeed been given up for two pawns, but other material imbalances may simultaneously apply (for example one player has a Knight, two Bishops, and six pawns, versus the opponent's Bishop, two Knights, and four pawns -- hardly the same thing as what we were looking for). So to be sure that we're getting a straight "Knight for two pawns swap" with everything else being equal we'll need to set up the dialogue like this:

In which we've ensured that one player has all of his minors while the other is down a Knight while being up two pawns. We did this by setting the Queen, Rook, and Bishop values to zeros, showing that there was no difference between the players in the numbers of these pieces.

There are tons of other imbalances you can look for by using the "Difference" box. Check your ChessBase 9 Help file for a couple of additional examples (one of which is fairly complex). And don't be afraid to experiment; you can't "break" a thing and can always use the "Reset" button to start over.

We'll have more on the Material Search dialogue in the next ChessBase Workshop. Until then, have fun!

© 2005, Steven A. Lopez. All rights reserved.