The Japanese translation of TLPI (published by O'Reilly Japan) will come out next month. Japanese readers can read (the Japanese translation of) a short preface that I wrote for the translation.
Although I will never be able to read it, I have a couple of reasons to believe that the translation will be excellent. First, the translation was done by a kernel developer, Junjiro Okajima (developer of the aufs file system). Second, along the way Junjiro has been extremely attentive in reading TLPI and checking details. As a consequence, he contributed a large number of errata reports (making up more than 20% of all current errata reports for TLPI), ranging from typos to corrections and improvements to rather deep technical details presented in the English text.