Introductory. In earlier papers of this series, Japanese forms are cited in a transcription that purports to be phonemic; the system that underlies the transcription is briefly outlined in the footnotes. On closer examination that system proves to be untenable. Instead of being purely phonemic, it is heavily influenced by unformulated morphophonemic considerations, and even, to some extent, by the traditional representation of Japanese in roman letters. There is room, then, for a new and more careful study of Japanese phonemics, based solely on the sounds that occur in Japanese utterances and on their distribution. Such a study is the object of the present paper. The dialect to be investigated is the modern standard colloquial, defined as the speech of educated persons native to Tokyo.