The following list includes a few books published in Japan (and written in Japanese). Thanks to Jim Kelly for submitting images of these books.
LEGO MINDSTORMS NXT Orange Book by Yoshihito Isogawa is a color Japanese book, which can be purchased from amazon.co.jp. The book presents a number of robots with building and programming instructions as well as tons of incredible ideas. Also be sure to check out the author’s LEGO TECHNIC Tora no Maki book.
LEGO MINDSTORMS NXT Gray Book by Shinichiro Oba and Takuya Matsubara is another Japanese title that covers a wide variety of topics: programming, computer-aided design, mechanical tricks, and even trignometry. It also features one very large robot called Betarex that uses 2 NXTs and 5 motors.
LEGO MINDSTORMS NXT Black Book by Oba Shinichiro is yet another Japanese title that covers the NXT-G programming language and a series of 4 robots. It has both color and grayscale pages.