a chess program by Wim Rens running under the Windows .NET framework. GambitVB plays reasonable chess, has an own GUI, and is open source. GambitVB is written in Visual Basic and time critical parts in none managed C++, incorporating old ideas of Wim Rens' earlier commercial program Gambiet, as well as old ideas not possible to implement with the hardware of the 80s. GambitVB is object-oriented, as described elaborately with UML class diagrams in a developer guide in MS Word format. The original GambitVB.info site is no longer available, VBChess 4.4.rar is hosted by Ron Murawski , and contains self-extracting executables for the sources, pdf and word document files.
GambitVB uses a 10x12 Board to apply alpha-beta with killer heuristic inside an iterative deepening framework with aspiration windows. Since GambitVB v2, the program performs some kind of best-first algorithm and keeps huge parts of the search tree in memory, which offers fast access to valuable move tree search informations, missing in the standard depth-first approach. This can grow up to millions of tree nodes linked to a tree structure, which is still a small fraction of the total search tree. So called Score objects, consisting of a vector of material balance and positional evaluation also considering game phases, are used to compare board positions as better, equal, or worse.