せいなんにほん 西南日本 LinksSentence search for 西南日本Sentence search for せいなんにほんKanji details for 西, 南, 日 and 本Edit in JMdict Noun1. southwest Japan (southwest of the Itoigawa-Shizuoka Tectonic Line)See also 東北日本 Discussions Log in to talk about this word.