Mishima's Sea of Fertility tetralogy was excellent. The second entry in the series, Runaway Horses, is in my opinion the 20th century's best novel. The fourth, with its surprising conclusion, was also astounding.

Much to my surprise, I've found that the books actually read better in English translation than they do in Japanese. Mishima was inordinately fond of using complicated, and sometimes archaic, Chinese-style (kanji) characters that even native Japanese readers have trouble with. His books flow a little bit more smoothly in English, and they don't seem to lose much in translation.