[mtlmtlmtlmtl]

Well, let me try to explain what I'm thinking, though I may have misunderstood you.

The rules of chess allows you to enumerate all the possible transformations from one board state to the next. This is just a fancy way of saying all possible moves in any given board state. By induction this means that given an initial board state and a series of moves from that board state you can determine the final board state.

So this means that the rules of chess allow you to enumerate given an initial state and n plies, all possible ways of adding an (n + 1)th ply.

So if you just assume the initial board state is always the starting position, theoretically you could do away with thinking about board states altogether. Now, whether that's sensible in terms of computational complexity is another question entirely and my intuition is no.

[YeGoblynQueenne]

>> So this means that the rules of chess allow you to enumerate given an initial state and n plies, all possible ways of adding an (n + 1)th ply.

Ah, I get you. Yeah, OK, makes sense. You can generate all legal moves from a starting board state given the rules of chess. Yep.