Hello Scidb users, I have a general question about FEN strings, but I would like to know how this is done in Scidb.
It is well-known that a FEN string contains a field about castling possibilities. It is also well-known that castle is possibile iff (i hope to be right! ) 1. King and interested Rook had never moved in the previous moves; 2. There is none piece between the King and the interested Rook; 3. None of the square through which the King should pass must be attacked by an enemy piece (or pawn). This includes the starting square (e1 or e8), i.e. the King must not be under check. Now my doubt is: what of these three rules are included in the FEN? I am confused becouse I found in some reference that the FEN for the initial position is [rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1] but in the initial position the rule 2. is not satisfied. From another point of view: If I give the initial FEN to an engine, it will look for 0-0 or 0-0-0 ? Or the engines check themselves the fulfillment of the rules 2. and 3. ? From a third point of view (the main, for me): While doing a game Parser/Viewer, to make a step forward (i.e. go ahead of one ply), the FEN must be updated, but with respect of what castling-rules? (Or, if you prefer, how this is handled in Scidb?) Regards
