In this article I seek to construct a social theory on legal arguments, in which I investigate semiological order in legal arguments. In order to pursue this structuralist goal, I reformulate Duncan Kennedy's Semiotics of Legal Argument into social theory. According to Kennedy, legal argument can be interpreted as a system that consists of 'bites' (for example no liability without fault) and 'operations' (for example counter theory). If Kennedy's insights are applied to Japanese legal arguments, in particular those on defense of necessity, similar bites and operations exist in Japanese legal tradition. For example, when a defendant employs NLWF, a plaintiff responds to it with 'innocent victim should be paid'. This finding means that structuralist models of legal arguments are useful in private law interpretations in various legal cultures.
