VB Micro Chess (Huo Chess)

IMPORTANT UPDATE: This code samples page is now obsolete! Find the newer versions of Huo Chess at http://code.msdn.microsoft.com/Huo-Chess-C-C-VB-micro-fea2bb87 or at http://huochess.codeplex.com/. See a detailed explanation of the Huo Chess algorithm at http://www.codeproject.com/KB/game/cpp_microchess.aspx.


VB Micro Chess (Huo Chess)

VB Micro Chess is a free and fully open source chess engine. The VB Micro Chess presented in this page is a Visual Basic port of the Huo Chess engine (http://archive.msdn.com/huochess). Huo Chess is developed and maintained by Spiros (Spyridon) Kakos (http://www.kakos.com.gr).
Please visit http://archive.msdn.microsoft.com/cshuochess for the C# Edition of Huo Chess.
Please visit http://archive.msdn.microsoft.com/xnahuochess for the XNA Edition of Huo Chess with Graphical User Interface.

Currently VB Micro Chess (Huo Chess) is at version 0.82 at a total of 59 KB in size.
Huo Chess plays decent chess and has managed to draw Microchess, but unfortunately will probably lose if it plays with Garry Kasparov :)
Its algorithm can be used to study the underlying logic of a chess program or as a basis for your own chess program. The source code is fully available and heavily commented.

The algorithm used in this program for the implementation of the computer thinking is the "Brute Force Algorithm." Huo Chess plays with the material in mind, while its code has some hints of positional strategic playing embedded. More analytically: When the program starts thinking, it scans the chessboard to find where its pieces are (see ComputerMove function) and then tries all possible moves it can make. It analyzes these moves up to the thinking depth I have defined (via the ComputerMove -> HumanMove -> ComputerMove2 path), measures the score (see CountScore function) of the final position reached from all possible move variants and – finally – chooses the move that leads to the most promising (from a score point of view) position (ComputerMove function).

For games played by Huo Chess and for an analytical explanation of its underlying logic, see http://www.codeproject.com/KB/game/cpp_microchess.aspx. (that page refers to the Huo Chess C++ version, however it applies to the Visual Basic version as well)

For a tutorial on how to develop a chess software application on your own see the How to Develop a Chess Program for Dummies tutorial at http://knol.google.com/k/how-to-develop-a-chess-program-for-dummies#. This tutorial is based on the Huo Chess and it is written by the creator of Huo Chess himself.

Huo to customize
Use Microsoft Visual Studio 2008 or Visual Studio 2010 to customize the code.
You can use the Huo Chess Opening Book Editor to create your personalized Opening Book for Huo Chess. You can find the Opening Book Editor at https://archive.msdn.microsoft.com/Release/ProjectReleases.aspx?ProjectName=huochess&ReleaseId=404 at the MSDN Huo Chess C++ edition home page. The folder with the opening book entries must be in the same folder as the Huo Chess executable (see the Huo Chess Opening Book Editor page for more instructions).
You can also add more thinking depth capability, by adding new ComputerMove functions (like ComputerMove2, ComputerMove4 etc.), change the value of ThinkingDepth variable and make the necessary adjustments to the HumanMove function (add another if at the point where it calls the ComputerMove functions). Moreover, you can also optimize the way Huo Chess thinks by changing the CountScore function and the way the computer values the pieces or the chessboard position. For example, if you change the score of the Queen in the CountScore function from 9 to 12, then the HY will play aggressively to attack the opponent's queen and at the same time try harder to defend its own queen. You can also — for example — give a high scoring to the existence of an opening column with a rook controlling it, so as to make the computer play more with its rooks and try to take over columns with them. Any FEEDBACK is WELCOME with better configurations of the Opening Book or the CountScore function!

Prerequisites: The program requires .NET Framework 2.0 or higher to operate.