Thematic Engine Matches in Chess Assistant

A thematic match between two chess engines can be started from any position in Chess Assistant. There are two ways to select the starting position for the games:

1. When examining a game in view mode a match can be started from the current position as it is displayed on the chessboard.
2. Create a database with the opening line leading to the thematic start position.

In both cases the games of the match will be saved with the full gamescore, beginning with the normal starting position. After each game of the match is finished it will be saved in the EngineGames database, which is automatically created if it doesn't exist.

Starting a thematic match from view mode

When viewing a game you come to an interesting position that you want to explore further by having two of your favourite chess engines play a series of games starting from that position. Let's take the position on the diagram as an example.
This position arises after the moves 1.e4 e5 2.Nc3 Nf6 3.Bc4 Nxe4 4.Qh5 Nd6 5.Bb3 Nc6 6.Nb5 g6 7.Qf3 f5 8.Qd5 Qe7 9.Nxc7+ Kd8 10.Nxa8 b6. Besides the Vienna move order shown here, this position can be reached via the Bishop's Opening (1 e4 e5 2 Bc4 Nf6 3 Nc3). The ECO code is C27, but this variation is better known under a name given to it by Tim Harding: The Frankenstein-Dracula variation. We want to see how modern chess engines handle this very complex situation.

From the menu bar select Engines > Engine-Engine > From current position. The following dialog box will be shown.



You start by selecting the engines that will play the match from the White and Black drop-down lists. In this case I have chosen two very strong engines, Shredder 9.11, which comes built into Chess Assistant 9, and Rybka 2.1c. The Options panel allows you to set various options for the match, but the only setting that I changed was to clear Ignore loss on time. The meaning of the different options are as follows:

• Start from initial position. If selected, the games will start from the normal starting position; otherwise they begin from the current position.
• Continuous. If selected, Max games will control the maximum number of games in the match; otherwise only one game will be played.
• Max games. If Continuous is selected the match will run for Max games and then automatically stop. There are also several different options for stopping a match manually at any time, as explained below.
• Change sides. If selected, the engines will switch sides after each game; otherwise the White engine will always play the white pieces and vice versa for the Black engine.
• Adjudge game result. If selected, and the losing engine evaluates its position to be worse than Adjudgment value (set in hundredths of a pawn) the game is stopped. This allows you to save time, but keep in mind that chess engines may evaluate some theoretically drawn positions as lost.
• Ignore loss on time. If selected, the engines will keep on playing despite losing on time.
• Max moves in a game. Maximum number of moves in a game. If a game is not finished when it reaches the limit, it is stopped and the result is recorded as unknown.

In order to set the time controls for the games click on Set time control, set Level type to Predefined and select Time per game from the drop-down list. Finally select the time controls from the list on the right-hand side of the dialog box:


Finally click OK to bring you back to the Engine - Engine settings. Clicking OK again will start the match.

The match can be stopped at any time before reaching the Max games limit by clicking on the STOP icon on the Engines tab. There are actually several options available when you click the arrow to the right of the icon:



All the options on this menu will stop the match, except Assign result which allows you to assign a result to the current game after which a new game will be started.

Defining the starting position with an opening database

Another way to organize a thematic match between two chess engines is by storing the opening moves in a database. You create a new database in Chess Asssistant by selecting Base > New... from the menu bar or via the keyboard shortcut Alt+F5. You can give the database any name you like, but for this example I chose C27-FD to remind me that this is a C27 opening database with the Frankenstein-Dracula variation.

Then create a new game containing the opening moves until you have the position from which you want the engines to play the match. A new game can be created by clicking on the Add new game icon (); by selecting Edit > Add new game... > Standard or simply by using the keyboard shortcut Ctrl+N. When you have entered the opening moves, save the game by clicking on the Save current game icon (); by selecting Edit > Save game or by using the keyboard shortcut Ctrl+S.

Now you are ready to start the match, so select Engines > Engine-Engine > From initial position. Note that this is slightly different from the previous example where a match was started from view mode. Then the match was started From current position, but now From initial position. This doesn't make much difference, but it saves you one mouse-click when defining the match! The familiar Engine - Engine settings dialog box is displayed.



In order to use the database you just created select Opening database and then hit the ... button to the right of the textbox and locate the opening database you created for the match.

This time we will define the time controls for the match using a slightly different method. Instead of picking the time controls from a pre-defined list we will define them manually. As before click on Set time control, but now select User level and then Time per game from the drop-down list. If we want the time control to be 1 hour plus 15 seconds added for each move, the dialog box should look like this when you are finished:



Finally hit OK to go back to the Engine - Engine settings and then OK again to start the match.