This study introduces an enigmatic construction in Japanese called chūshakuteki nibun-renchi ‘annotative dual-clause juxtaposition’ (ADCJ), exemplified below: Hiro wa, dare ni au no ka, resutoran o yoyakushita. top who dat meet nmlz int restaurant acc reserved Lit. ‘Hiro, (I wonder) who (he) will meet, reserved a restaurant.’ This construction is ubiquitous and yet little known even in Japanese linguistics circles. Because the matrix predicate of ADCJ cannot semantically accommodate such a component as dare ni au no ka ‘who (he) will (...) meet’ above, this paper argues that ADCJ is parenthetical, a construct that should be recognized as an essential element of verbal communication and, in turn, a determining factor in how utterances are to be formed and interpreted. This construction is dissimilar to any other type of parentheticals hitherto reported in the literature. What is so special about it is its merger of portraying two situations through abduction and expressing the entire circumstance in a single communicative unit. For example, in the above example, the parenthetical element explains why the speaker wishes to convey the matrix statement. From an interactional perspective, the primary function of ADCJ is to highlight the speaker’s intellectual and communicative involvement in the depicted scene. This style of communication, when compared with an ‘objective’ and apathetic description, is likely to induce more earnest reactions from the hearer or reader and, consequently, promote a more favorable continuation of the conversation or reading. This paper advocates a wide-ranging examination of thetical grammar (Kaltenböck et al. 2011), for which detailed analyses of constructions such as ADCJ that traditional syntactic/semantic theories cannot capture are indispensable. (shrink)