During an era marked by suspicion, and recurrent failures of ‘humint’ (human intelligence gathering), Cold War decision-makers were increasingly captivated and guided by the prognostications and intimations of ‘sigint’ (signals intelligence), ‘comint’ (communications intelligence) and ‘elint’ (electronic intelligence): that is, intelligence gathering through the interception and interpretation of electronic or electromagnetic signals and communications. Decision- and policy-making under the rubric of international law engaged continually with the would-be, could-be or might-have-been moves of key protagonists, as those moves appeared in electronic data. International legal order came to be marked, during the Cold War, by the latent or virtual agency of these overlapping ‘data shadows’ in ways that leave an enduring legacy today. This is demonstrated here by brief discussion of two instances of international conflict, and associated legal analysis, in ‘the “hottest” theatre’ of the Cold War: Asia.