@chironik #6 usually the opening will not change, except there is a move transposition. For example the modern opening 1.e4 g6 can transpose to Pirc (1.e4 d6 2.d4 Nf6 3.Nc3 g6) after 2.d4 d6 3.Nc3 Nf6, or to Kings Indian (1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6) after 2.d4 d6 3.c4 Nf6 4.Nc3 Bg7. But i dont know any transpositions to other openings after 1.e4 e5 2.Nf3 Nc6 3.Bb5, that is and will be Ruy Lopez. But it is possible for other openings to transpose to Ruy Lopez, for example 1.e4 e5 2.Nf3 d6 (Philidor Opening) can transpose to Ruy Lopez lines if Black later plays Nc6 (he usually doesnt) and if white answers Bb5.
Or, in short, chess openings are categorized by board positions and not by the moves leading to them. The last board position wins and indicates the opening.
Or, in short, chess openings are categorized by board positions and not by the moves leading to them. The last board position wins and indicates the opening.