meanwhile, i know that this is a common problem and attempted to reduce the number of faces in that particular area or move the vertices in order to get a better result. but it does not work how i want it to work! could you give me some advice? is there a better way to model a bishop?
Forget the Boolean modifier it will give you lousy results and especially so with subD modeling.
What you need to do is manually subdivide and slide edges until you have the shape you need. I have modeled the bishop and uploaded it as a demonstration of this method.
