rabbitoid: It could be played on real boards. It'd be a hassle, but it isn't unprecedented. That is how Kriegspiel was and is done. Kriegspiel is a game that is over one hundred years old. It is very similar to Dark Chess, but uses checks and checkmates and does not allow moves that are illegal in regular Chess, such as moving into check or castling through check, or moving a piece over a piece.

I have read that the opponents would typically sit in different rooms and require the services of three people to play a game of it. Each would have their own board and pieces, but would put them where they thought the opponent's pieces were. One of the people helping with the game would keep his own Chess board with the actual position on it that neither player could see. Unlike Dark Chess, the players have no way of seeing where their pieces attack or capture except to try the move and learn from what happens. One of the people helping with the game is given the role of referee or arbitrator. He announces if a move is legal or not. A player that makes an illegal move, must take the move back and try another. This is not how Dark Chess is played. It certainly would use the same skills to play as Dark Chess, but you'd have to gain a lot of your information just by what moves are allowed and also choose those moves that might be illegal on purpose to gain such information.

I imagine nowadays someone might have programmed a computer to play Kriegspiel. It seems this game has a following. I read it was used in training to help officers of the Prussian military learn about thinking with incomplete information.