LEGEND II....... Risc Style Technology
What the Box says about LEGEND II:
- Strong Program ELO rating 1950 (USA 2100) (estimated)
- 100 Levels of Play
- User programmable evaluation function
- User selectable playing style
- User adaptable playing style
- Very large opening book
Excerpts taken from the Excalibur “Legend II” Box back cover.
CHANGING STYLES..... Your computer can play 9 different “styles” ranging from ultra-cautious play when the program is White and ultra-aggressive play when the program is Black (style number 1), to ultra-aggressive play when the program is White to ultra-cautious play when it is Black (style number 9). The normal style of play is number 5.
WHY NOT?..... After the computer has made a move you can ask it the question “Why did you not play .....” and suggest a different move. The computer will then tell you what it expected you to play in reply if it had chosen your suggested move. (This will not always be the best move but it will be a move which the computer considered strong enough to counteract your suggested move.
USER PROGRAMMABLE EVALUATION FUNCTION..... Every chess program needs to know how to evaluate a chess position. It does so using an “Evaluation Function” which gives a point-score to various features of the chess position, such as king attack, material, mobility, centre control, etc, Associated with each of these features is a “weighting” which tells the program how much importance to attach to a feature.
Your chess computer allows you to change these weightings so that you, the user, are programming the computer to play in a particular way. For each feature the normal weighting is 10. The minimum weighting is 0 (when this feature would be completely ignored) and the maximum is 99 (when this feature will be given 10 times its normal importance). The features are:
- Pin against the enemy queen.
- Pawn structure around the king.
- King attack by pieces.
- Aggressive play by White’s pieces.
- Agressive play by Black’s pieces.
- Doubled pawns.
- Rooks on open and half-open files.
As an example of fun you can have, try changing the weighting of the “king attack” feature to 99 for both White and Black. This will make the program play very aggressively.
Excerpts taken from the Excalibur “Legend II” User Manual.