From the Prussian war game that needed a human umpire per table, to a war fought and refereed by machines that anyone can drop into.
Kriegsspiel (1812) trained real staff officers by trusting a human umpire: officers wrote orders in plain language, the umpire adjudicated with judgement and kept each side’s picture incomplete. It never became a mass game because every table needs its own expert referee. For the actual rules history, the Kriegsspiel literature is the right place — this page is a lineage claim, not a rules reference.
The Battleground keeps what made Kriegsspiel work — simultaneous orders, fog held by the referee, a front that does not care what you intended — and removes the last human bottleneck: the soldiers themselves fight around the clock, and a visitor drops into one mid-war instead of waiting for a table to fill. Orders lock on a shared tick; the machine adjudicates every one of them at once.