@0verSky
Not necessarily, since it's a real place. It's the obelisk (the 3 kings meeting happened here, and it's the "castle of the kaiser").
Though it's not clear why he dreamed of the match taking place here back in Air Poker, and why the match seems to actually be happening here.
Maybe it means he proposed the location to Souichi, to set up some trick that he was already thinking about during Air Poker?