by Steve Lopez

Shootout works from any legal chess position; thus you can start with a middlegame position or even from the initial position for a game of chess. But keep in mind that if you launch Shootout from the standard starting position, it does not use any opening books -- the engine functions on its own right from the gate.

Let's assume that you're going to start Shootout from a late opening or early middlegame position (you can either set up a position by hand or else load an existing game from the database and click on the position from which you want to start the Shootout). Go to the Tools menu, select "Analysis", and then select "Shootout" from the submenu. You'll then see a dialogue which looks like this:

This is where you'll set up the parameters for your Shootout-- and it's also where you'll see the new Shootout features. The first thing you need to decide are which engine (or engines) you're going to use for the Shootout. This is one of the key features of Shootout: the ability to have more than one engine play against itself from a particular position. To add an engine to the Shootout list, click the "New" button to get the engine selection dialogue:

This is just the standard engine selection dialogue which we've encountered before when using a lot of other functions in Fritz. Just select an engine, set any options/parameters, and click "OK". You'll see its name appear in the white box to the left of the "New" button. You can select additional engines for the Shootout; keep in mind that the engines do not play against each other -- in Shootout mode, an engine always plays against itself.

After you've made your engine selection(s), you'll next need to determine whether the engine will play against itself in a timed mode or a fixed search depth mode. If you want the engine to play out the position using a "sudden death" time control (such as a ten-minute game, a thirty-minute game, a sixty-minute game, etc.) click on "Blitz game" in the box on the upper right side of the Shootout dialogue. You'll then see the Blitz Game dialogue which will let you set the time controls. If you want an open-ended game (such as forty moves in two hours, etc.) click on "Long game" -- you'll then get the "Long game" dialogue which will let you set the time control you want. And if you want a fixed depth (in which the engine will always search to a depth of x plies before it moves) select "Fixed depth".

Note that the "Depth" box in the Shootout dialogue is always in half tone ("greyed out") unless "Fixed depth" is selected. If you select "Fixed depth", this part of the dialogue becomes available to you. In the "Depth" section, you'll select a range of depths at which the program will play. It's easier to understand this if we look at an example. Let's say we set the lefthand depth box to "9" and the righthand one to "13". In this case, the engine you've chosen will actually play five games against itself: one game in which it will always move after completing a nine ply search, one game in which it moves after ten plies, one in which it moves after eleven plies, etc. So you can have the engine play multiple games and see if/how it handles the position differently as the search depth is increased from game to game.

"Skip even plies" changes this behavior somewhat. If you set the dialogue for "9" through "13" and check this box, you'll get just three games instead of five: it will play games using search depths of nine, eleven, and thirteen plies -- skipping over "10" and "12". There's a reason for using this setting: some chess engines (particularly older ones) become somewhat tactically "blind" at even-ply search depths (they fail to consider responses to surprise moves by the opponent and neglect defense a bit). So you'll tend to get better play with these older engines if you check the "Skip even plies" box.

Finally you can set a move limit to the games -- this is the maximum number of moves that will be played before the program stops the game. Most Shootout users want to see the immediate tactical and strategic possibilities from a given position and aren't interested in seeing a long, drawn-out technical endgame that might occur forty moves later. I usually leave this set to "99" (the maximum setting); however if a long endgame does occur and the program cuts the game off prematurely, I can always load that final position and set up another Shootout which starts there.

Once you've set the Shootout parameters, click "OK" to start the Shootout and the games will begin, using the parameters that you've selected. Here's an example of a Shootout setup. I've picked both Fritz8 and Crafty with a ten-minute blitz time limit and a maximum move limit of "99":

In this example, Fritz8 will play a single ten-minute game against itself starting at the position I've selected. When that game ends, Crafty will then play a ten-minute game against itself starting from the same position. If I'd selected a range of fixed depth levels, each engine would play multiple games against itself using those fixed depth parameters.

Shootout games are automatically saved into the EngMatch.cbh database so that you can replay them later.

The Shootout is a wonderful tool for players who want to see how a particular position might be handled. It's also great for computer chess buffs who want to see how various engines handle a given position differently from each other, or even how the same engine will handle it at a variety of ply depths.

Until next week, have fun!

© 2003, Steven A. Lopez. All rights reserved.
Back issues of Electronic T-Notes from 1997 and 1998 are available on the ChessBase USA web page