This paper discusses four distinct functions of the Japanese particle mo, namely, (i) the universal quantificational use of mo with an indeterminate; (ii) mo within a negative polarity item containing an indeterminate; (iii) mo within a negative polarity item functioning as a minimizer; and (iv) additive mo. Starting with Shimoyama (2001, 2006) and a significantly modified adaptation of Kobuchi-Philip`s (2008a) analysis of universal quantifcational mo, this paper proposes a unified semantic analysis of all four uses of mo. It is argued that X-mo is syntactically an adjunct, and that its semantics involves (i) a condition of membership in the denotation of the DP construed with the mo-phrase (the Condition of Inclusion in Moltmann 1995), (ii) a condition of membership in the predicate denotation, and (iii) a condition requiring the existence of an additional element with the same properties as the referent of what mo syntactically combines with.