I think, Ilga preuss, also thinking according to the idea, I have presented, this will be more effective, and effecient, If you use, polymorphism the unknow objects will be known, at compile time, due to polymorphic behaviour, you will use an custom define interface, like GamePiece, then implement each new class with this interface, with names, like Knights, Queens, Rocks, thus you got the knowledge of unknown object at the casting time, it will help you,
If you still got problem try to write your program, so that I could get it, and try to understand what exactly you want to do.
Please don't be so persistent to Strings, try other behaviours (~_~)
A Java Student
Saif Ullah
SCJP2