The 'logic' of a language generally refers to the way it expresses reality. Japanese is accused of being 'illogical' because in Japanese discourse, mappings from reality to linguistic elements and structure are highly diversified and make the interpretation of texts difficult. In particular, ommission, weak logical links, the absence of signigicant informational contributions from grammar, a tendency to mix logical categories, rapid and unruly lexical innovation and an alledgedly careless attitude of Japanese authors towards their language result in comprehension difficulties, especially for translators. The present article discusses a number of principles which can help translation students deal with those problems: the analysis principle, the separation principle, the doubt principle, the author-is-no-fool principle, the daring decision prinicple, the test loop principle and the block analysis principle.