Even big, serious war games like Advanced Squad Leader had some limited fog of war mechanics. Concealed units could get a '?' counter on top of them, and if you

Even big, serious war games like Advanced Squad Leader had some limited fog of war mechanics. Concealed units could get a '?' counter on top of them, and if you start with concealed units, you often got a whole pile of '?' counters to spread around, and your opponent would have no idea which had real counters underneath and which had just more '?' counters underneath. It's much more limited than what computers make possible of course, but it worked well enough.