I think that’s actually a really interesting idea. I would play them. I’m almost tempted to implement them, but I don’t feel like trying to implement an AI opponent.
I liked Chess when I was younger, but started playing wargames that were more like simulations, and developed a distaste for Chess precisely because it is too predictable and would lead to out-predicting all the moves, which I was far less interested in than moving all units every turn and having probabilistic combat results based on unit strengths and terrain and so forth.
So, I think I might enjoy Fog-of-Chess at least for a bit, because it would add new sorts of strategies – scouting and predicting and feinting and so on. The game would be different depending on how you defined which units could see how far and in what directions.
Fog-of-Go would also be rather different and interesting. You would not know in the first several moves where the enemy was playing, unless you happened to place pieces in range of your opponent each time. The spotting range would again make for different games depending on what you set it as. There would be a guessing game about the undiscovered pieces. It would be rather different from Fog-of-Chess because in Go the pieces don’t move once placed (unless eliminated), so unless the spotting range was only 1 or 2, the effect would be greatest at the beginning and get less at the end.
In both games, the guesswork could tend to dominate the traditional strategies, and mitigating risks would be a new skill people would need to learn, as well as moves to gather information and (in Chess) screen your own units from discovery.
@elbanditoroso It could be done in a physical game if you have three sets and employ a referee who tracks the game position on a set the other players can’t see. The other players move their own units on their own set, and the referee lets them know if they’ve revealed (or run into) enemy pieces, and where.
An alternative could be to have a Chess set where the pieces all look alike but say what they are only on the side facing the owning player (and if players were allowed to place their pieces where they wanted during setup, ala Stratego).