by Steve Lopez

Last week we saw the basic ideas behind opening keys-- what they are and what they do. This week we'll start building a key from scratch. There are several things you'll need to accomplish before you start building a key. First you'll need to create a database of games using the opening in question. If you're not sure how to do this, refer to the ETN issue for March 11, 2001 for the specifics. (By the way, you'll also notice instructions on how to transfer an existing opening key [or portion thereof] to another database. If an existing portion of a key will do the job for you, just follow those instructions -- this current series of articles then becomes irrelevant. The reason we're building a key from scratch here is to learn how to do it, for example in the event you want to revise or refine an existing key).

Once you've created a database of games on your selected opening, you'll then want to create an opening tree based on those games. Here again you can refer to a previous ETN issue for instructions: March 18, 2001.

In this example, we'll use the Ruy Lopez Exchange as our opening. Once a database of Ruy Exchange games has been created, double-click on its icon to get the game list. Click the "Openings" tab at the top of this display and you'll see this:

You'll always see this display when you click on the Openings tab in a database for which no opening key exists. If you want to create an opening key from scratch (as we do in this article), click on the "Install empty key" button. You'll get a new window, similar to the game list display, with the single entry "Key is empty". This indicates that the opening key files have nothing in them; but this is good news because we can now start making our own keys.

You'll first want to create a "root" key. You have two options for this: either a verbal key that has no position assigned to it (kind of like a title page), or a root key that has the basic position for your opening assigned to it. I typically opt for the latter method in my own keys (it saves a step), but we'll look at both of them here.

To insert a new key, just hit the Insert button on your keyboard. This will start the process of creating a new key by displaying a dialogue that shows the last board position you were looking at in either a game window or a game tree window. So let's create a root key and see how this works. You'll recall that the Ruy Lopez Exchange is defined by the moves 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6. At this point you cam either use the opening tree you created to step though the moves to get to this point, or else open a new board window and play the moves by hand. Go to the Windows Taskbar and click on the button to bring your opening key window back up on top. Hit Insert on your keyboard and you'll see a new dialogue that looks like this:

This shows the position that will be associated with the new key (the position ChessBase will use when classifying the games, as described in last week's ETN). If it's the correct position (as this one is), click "OK". You'll then see a text entry box -- this lets you determine how the key will visually appear in the key list. The default given in the text entry box is the move sequence up to that point (in this case it's 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6):

I'm going to change this by replacing the first three moves with some text:

Note that this doesn't alter the board position associated with this entry in the key. You can type literally anything in this box, and the associated position will still be the one after 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6.

When you've finished editing the text, click the "OK" button. You'll now see the key window looking like this:

The words "Key is empty" have been replaced by the new key entry. Note the "0" on the far right -- this means that no games in the database as yet match the position. This is because we haven't classified the database games yet; we'll do that later.

This key is basically the "title page" for our new opening key. Another way to create something similar is to create a "title key" or "root key" with no classification position assigned to it. In this caes, you could just hit Insert without first playing though some moves in either the tree or in a board window. A different dialogue appears which informs you that no classification position has been assigned. Just click "OK" and you'll still get the text entry dialogue, but this time it'll just show a couple of dashes instead of a series of moves. We'd replace the dashes with the same text we used above, click "OK", and wind up with the same thing.

Going to our opening tree, we see that after 4.Bxc6, Black has two moves: 4...bxc6 and 4...dxc6. So we'll now need to create a couple of subkeys for these two responses. In our opening key, we'll double-click on the line that says "Ruy Lopez Exchange Variation: 4.Bxc6" and get a new display:

We've gone down one level into our key index. All we see here are two dots. These dots are actually important. If you double-click them, you'll go back up one level (that is, back to the previous next-higher key in the hierarchy of moves). In this current display, we'll create two new keys for Black's two responses. In either our tree or in a board window, we'll make the move 4...bxc6. Then we'll return to the key window and hit Insert just as before. After clicking "OK' in the classification position dialogue, we'll get a text entry window showing all of the moves through 4...bxc6.

In order to keep our key from being too cluttered and "busy", we'll want to edit this text so that it displays just "4...bxc6" before clicking "OK". We'll then see two entries in this key list: the two dots at the top and the extry for 4...bxc6.

Next we'll want to add a second entry for 4...dxc6. Take back the move 4...bxc6 in your tree or board window and make the move 4...dxc6. Then return to the key.

Now it's time to note a crucial behavorial habit of the key display. When you hit Insert to add a new key, it will always appear in the list directly below whatever key you currently have highlighted. So if you want 4...dxc6 to appear as the next entry underneath 4...bxc6 in this list, you'll need to single-click on 4...bxc6 before you hit the Insert key. (Note that you can move keys up and down in the list, and we'll look at this later. But if you get in the habit of highlighting a key before inserting a new one, it'll save you some work later).

After highlighting 4...bxc6, hitting Insert, clicking "OK" editing the text to read just "4...dxc6", and clicking "OK', you should now see a display like this one:

And we now have our two subkeys for Black's fourth move responses to 4.Bxc6.

It's important to note that you can delete keys if you make a mistake. Just highlight the key by single-clicking on it and then hit the Delete key on your keyboard. After you click "Yes" in the confirmation dialogue, that key will be deleted.

Note also that you don't have to "Save" your work when creating or deleting keys. Everything in this process is saved automatically by ChessBase.

Now we have a very basic opening key established. We can further refine it by adding new subkeys, and that's what we'll consider next week. Until then, have fun!

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