 Heytesbury’s obligationes are zero-sum and dynamic consistency games participated in by two players, an “opponent” and a “respondent”. The opponent posits a “casus” (ponitur casus), i.e., the initial linguistic and extra-linguistic assumptions, and proposes particular sentences. The respondent admits or denies the casus (admittitur, negatur casus) depending on its consistency and concedes (concedo), negates (nego), or doubts (dubito) the proposed sentences, the criteria being logical relations to either the casus or to the totality of preceding moves (including the casus). Heytesbury chooses the latter option, thus subscribing to so-called “antiqua responsio” (Read 2013: 20–23). The respondent wins if he maintains consistency.