There have been two major lines of analyses on the so-called thematic use of wa: (i) the topichood-based analysis: 'Wa marks a topic' (e.g., Mikami 1963;Kuno 1973;Noda 1996;Portner and Yabushita 1998) and (ii) the groundhood-based analysis: 'Wa marks given/old information' (e.g., Martin 1975;Ono 1978;Makino 1982;Fiengo and McClure 2002).
4 a major portion of existing analyses of wa amount to the following, two competing hypotheses.