Recent SLA studies have reported that optionality phenomena are observed even in L2 grammar at near-native or advanced levels, and those studies concluded that L2 learners have problems in the syntax-discourse interface, but not in their syntactic representation (Sorace 1993, Robertson and Sorace 1999, Sorace 2006, Sorace and Filliati 2006, Sorace 2007). To date, little research on the use of Japanese pronominals in SLA discourse has been conducted. Hasatani (1991) examined Japanese essays written by elementary English and French of Japanese learners and found that they showed asymmetry in use of null pronouns: they dropped more subjects than objects. Does such asymmetry still exist in advanced L2 grammar? Do advanced learners show optionality where both overt and null forms are allowed to be topic-referring in topic context? This paper reports an experiment with 5 L1 Korean and 5 L1 English learners of Japanese, as well as 5 native speakers of Japanese as controls. The results reveal that only L1 English learners show a pseudo asymmetry: they dropped more subjects than objects, and produced more overt forms (full NPs) in the object position in topic context than L1 Korean learners and Japanese native speakers. A cross-linguistic influence still seems to be involved in their advanced grammar. The author concludes that the preliminary data from a forced-written elicitation task supports Park's (2004) syntactic account.