The exoneration of former death-row inmate Iwao Hakamada has been in the news lately:
http://www.npr.org/blogs/thetwo-way/2014/03/27/295162651/sentenced-to-death-46-years-ago-japanese-man-is-now-free
For an audio podcast (and text transcript) about this case see
http://www.npr.org/2014/04/06/299708675/japan-releases-inmate-after-nearly-half-centure-on-death-row
This first person to be exonerated in this way was MENDA Sakae of Kumamoto in 1983:
http://en.wikipedia.org/wiki/Sakae_Menda
There has still been only a handful of such exonerations in Japan.
Sentenced To Death 46 Years Ago, Japanese Man Is Now Free
Iwao Hakamada, now 78, is thought to have been awaiting execution longer than anyone else in the world. But newly analyzed DNA evidence has led to an order that he be retried.