Chess Opening Theory/1. h4/1...d5

=Kadas Opening=

1...d5
Black takes the center and opens the diagonal for the light-squared bishop, preventing White's kingside rook from coming out with 2. Rh3??, to which Black will respond with Bxh3. White may try to rectify this with 3. h5?!, but this allows Black to take the full center with 3... e5! not allowing the rook to come to h4 either.

Responses
White may respond to the move d5 with:
 * /2. h5/, allowing Black to take the full center with 2...e5,
 * /2. d4/, which is more principled, and White will always play d4 in this opening so why not?
 * or 2. Nf3, controlling the center with a knight and either going into a King's Indian-like defense, playing classically, or just transposing into the d4 line.