The Signal experimental wargame is a three-player, turn-based strategy game designed to study decision-making concerning the use of conventional and nuclear weapons. The research objective is to explore how weapons capabilities shape player behavior and the resulting impacts on strategic stability and the potential for escalation in a crisis. The board game serves as both a source of experimental data and a testing ground for the ruleset and game dynamics that were subsequently built into the SIGNAL online platform. In SIGNAL, players choose courses of action that a hypothetical nation might follow, using economic, military, and diplomatic means. Players may choose to cooperate with or compete against the other players in the virtual world to grow their infrastructure and gain resources while avoiding loss of home territory to conventional militarized invasions or nuclear war. The game proceeds in rounds, with players maneuvering their forces within a map-based environment. Players work simultaneously, often negotiating agreements such as trade deals or military alliances, and “signal” to others by placing tokens on hexes (units of land or water). The signaling token is accompanied by the staging of cards (face down) that reflect actions like building cities, sending troops to neutral territories, or engaging in military operations, including the use of conventional or nuclear arms. There is a price associated with signaling; players pay for each card placed, regardless of whether the capability is exercised to reflect the “costly signaling” or “credible commitments” in the existing theoretical literature on deterrence. Players may then exercise their staged actions, but only at locations where signaling tokens were previously placed. During this action phase, players take a series of turns, starting with a randomly chosen player to ensure that any given player does not have a constant first-mover advantage. After five rounds, players are ranked on a relative scale based on their infrastructure, resources, and territorial integrity to determine the winner—with a player’s cumulative performance captured on a leaderboard. —description from the designer