Some argue that Japan fudged its numbers to hide the drop in GDP following the crisis, and was waiting for reality to catch up whilst reporting stagnation for a few years.
Depends on your definition of credible evidence, and your personal theoretical bias, as with most things in economics (see: China bull vs bear case).
My position on the matter is "I don't know, and I'm unwilling to invest the effort to know"; the extent of my interest in Japan is how the ever lowering JPYSGD makes for good value holidays. But it was an interesting theory worth chucking in.
I've also seen some interesting playing around the components of CPI in Japan and elsewhere, taking them in and out of the index as required to obtain the right result. Can't find a link, unfortunately; it was probably a paid bank research report and I've been out of the field for half a decade.