As the title says, and I have a concrete example in mind, g5 attack against the Italian:
[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3 h6
5. O-O d6 6. c3 g5
Which can go like this:
[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3 h6
5. O-O d6 6. c3 g5 7. Re1 g4 8. Nfd2 h5
9. Nf1 h4
It is a really interesting opening and probably results in some beautiful attacks; however, it violates so many opening principles:
- Black does not develop pieces
- Black does not get their King to safety
- Black makes a lot pawn moves in the opening
The reason we learn about opening principles is that they work in most situations, could playing this opening mess with a players judgement in an unknown position? Would the answer differ depending on a player's level?