What is "Blu-spec CD"?

These are starting to be released in Japan. What exactly are they and how do they differ from redbook in technology and sound?
a music disc that is made for blue ray players, but will also play in standard players as well....in other words, 'here we go again'.
supposedly the cd's were burned with a blue laser which is more accurate and reduces jitter.

they differ in that they are burned with more precise blue laser

normal CD vs blu-spec CD

but Blu-spec CD's are still low resolution CD format we know since year '82.

I'm curious whether Sony will also decide to release Blu-spec SACD's , that would be nice...
Thanks all! I will check out the provided links.
Might have to try Blu-spec CD "Kind of Blue" (no pun intended) being released in Japan 12/24/08. We'll see what's up with this!