This paper proposes a new approach to the Mandarin focus/quantificational particle dou, according to which dou signals a subquestion-based discourse strategy and imposes a particular constraint on how the subquestions are answered. In particular, the universal/distributive dou requires that all subquestions of the common question-under-discussion (QUD) be positively answered, whereas the scalar, even-like dou represents a special strategy where a QUD is completely resolved by the positive answer to just one subquestion, the one that is least likely to be positively answered. The proposal makes a strong connection to contrastive topic (CT) constructions in Mandarin and suggests that different kinds of dous (i) are morphological variants of the clausal operator independently needed for Mandarin CT and (ii) agree with optionally co-occurring elements such as bulun 'regardless of' and lian, which are subquestion-sensitive quantifiers. Several puzzles, including the free-choiceness of two distinct free-choice constructions, as well as the comparison with recent accounts, are also discussed.