A discussion of the role of the Japanese language in the English-as-a-Foreign-Language (EFL) classroom in Japan presents several arguments in favor of using Japanese, followed by some notes of caution and a call to teachers to reflect on their classroom language use. Arguments for using students' native language (L1) include these: in mixed level classes, less advanced students can be easily left behind if only the second language (L2) is used; the L1 can provide a natural bridge for overcoming problems of vocabulary, sentence structure, and confidence; when an ESL writing topic is originally acquired in the L1, its use supports student planning; L1 can assist lower-level students in generating ideas that can then provide fuel for further oral or written language use; providing meaning for new vocabulary through translation has advantages over inductive approaches, particularly in acquiring abstract concepts; translation of whole passages can make relatively difficult texts comprehensible; and L1 use can save time and have a positive effect on the teacher-student relationship. Teachers are cautioned not to let the L1 dominate or persist in classroom communication, and to consider carefully their reasons for glossing any English word in Japanese. (Contains 23 references.) (MSE)