Introduction  It has been pointed out that in Japan the language barrier prevents non-native Japanese speakers from accessing medical services and health information. “Yasashii Nihongo” is considered as a way to overcome this barrier. This is not the language native speakers use but a version adjusted to suit the audience’s Japanese ability. This study aimed to describe nursing students’ skills in rewriting Japanese medical information for non-native Japanese residents and knowledge for the skills and to examine a trial intervention to improve their skills and knowledge.Methods  A cross-sectional study and an interventional study were conducted. In each study, data were collected through self-reported questionnaires targeting nursing students. Their skills and knowledge were summarized. The associations between skills and knowledge were examined, as well as the association between skills in rewriting two example sentences. In the interventional study, a workshop teaching “Yasashii Nihongo” was offered to participants. Changes in skills and knowledge after the intervention were also assessed statistically.Results  In the cross-sectional study, a median general score to assess skills was four out of five, and the number of knowledge items was two out of sixteen.  In the interventional study, an association between skills in the two example sentences was found (p-value = 0.04). However, there was no significant difference in skills or knowledge before and after the intervention.Conclusion  In the cross-sectional study, participants suggested only few knowledge items of “Yasashii Nihongo”, but they suggested high skill scores. In the intervention study, we could not confirm the effectiveness of teaching “Yasashii Nihongo”. To increase the knowledge level of nursing students and to use the knowledge in actual rewriting, it is necessary to reconsider the teaching contents and to allow appropriate time for the intervention.