Deciding whether a single chess position is reachable can be really hard. There is a whole class of so called "retrograde" chess problems focussed on that.
For example, is the following position reachable?
White: Kc3 Ba4 Black: Kd1 Rb5 Bd5
Deciding whether a single chess position is reachable can be really hard. There is a whole class of so called "retrograde" chess problems focussed on that.
For example, is the following position reachable?
White: Kc3 Ba4 Black: Kd1 Rb5 Bd5