The newest issue of the tabloid Bubka is reporting on a rumored tell-all book coming from Kago Ai. We have no more info on this article other than the headline though (seen here).
There has been lots of other talk about Kago lately as well, due to an advertisement seen in a recent magazine and on subways that says the following:
Kago Ai 100 Million Yen Nude Project In Progress
This was also picked up on at least one news broadcast:
As this is all the info to be had so far, it's quite open to interpretation. It very well could be that this is the same thing Bubka is referring to: A fully-revealing ("nude") tell-all book. Or, perhaps the Bubka article is completely separate, and Kago will indeed be shedding her clothes for photos in the near future. The image used in the news broadcast has some hard to read text (presumably from another tabloid), but the following can be seen there:
"attention from the porn industry"
"project is in progress"
"'300k pieces would sell for sure!' says publishing producer"
Only time will tell, but any reports of Kago confirmed to be posing nude, or offering her nude modeling services are based on conjecture for now. We'll update this article with more info as we get it.