I lived in Japan for 4 years, so I learned a bit about Japanese science fiction.
In 2007, I went to the WorldCon in Yokohama.
A lot of Japanese SF isn’t translated and so is hidden to English readers.
A new American company, Haikosaru is aiming to translate some of the best of recent Japanese SF.
Haikosaru’s web site claims that –
With a small, elite list of award-winners, classics, and new work by the hottest young writers, Haikasoru is the first imprint dedicated to bringing Japanese science fiction to America and beyond. Featuring the action of anime and the thoughtfulness of the best speculative fiction, Haikasoru aims to truly be the “high castle” of science fiction and fantasy.
One of their first titles is “All You Need is Kill”.
They have an interesting article on some of the differences between American and Japanese SF.