The Eschaton debacle — "each of the 400 dead tennis…"
each of the 400 dead tennis balls in the game’s global arsenal represents a 5-megaton thermonuclear warhead. […] On the open expanse of contiguous courts, Combatants are arrayed in positions corresponding to their location on the planet earth as represented in The Rand McNally Slightly Rectangular Hanging Map of the World.
Context
Interdependence Day, 8 November YDAU: the long exposition of Eschaton, as Hal would explain it "if Hal had a Luger pointed at him." The map's founding charter — dead balls stand for warheads, and the players' positions on court are keyed to a literal hanging classroom map (whose Rand McNally provenance is endnote 122, below). Everything that goes wrong later goes wrong inside the representation established here.