Functionally everything works on the chess board except the chess check during castle tester in the vector. It is like it doesn’t write the rule into pseudoLegalMove. Can a vector work for this type of thing? I am new C# and i’m learning and have spent days trying to fix this problem. My thoughts are I need to instead do this check in a bool or something so it writes the illegal move into pseudoLegalMove. Also everything else is working correctly…like enpassant, doublepawnpush ect. Any help from someone who has coded a chess board would be fantastic!