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[Tord Romstad]

What do you guys use the square color for? I can't imagine that this could possibly be a performance bottleneck. I compute the square color in the most straightforward and stupid way possible, and it still doesn't show up in the profiler output at all. Currently I use the square color for the following purposes:

• Testing for opposite colored bishop endgames (only done in the endgame, and only when both sides have no minor pieces except a single bishop).
  
• Evaluating knights and bishops on weak squares. The bonus is increased if the other side has no minor pieces except a single bishop (or no minor pieces at all), and this bishop is of the wrong color.
  
• Evaluating KBN vs K endgames. The color of the bishop's square is used to drive the king into the right corner.
  
• Detecting KBP vs K draws with a bishop of the wrong color.
  
• Printing an ASCII board.

Most of these don't occur except in very rare cases. I guess that I use my square_color function less than once per node, on average.

Tord