Arashi will release a compilation album called "Ura Ara(shi) Mania", which will consist of 62 songs: 49 are b-sides, and 13 other songs. They will include "rare" tracks, songs that are popular in concerts, and hidden tracks. The album package will not include photos of the members.
The preorder starts 8/16 to 8/23 (24:00) and is only available through J-Storm website, and only those with a valid Japanese address may order. (at least for now) The listed price is 6,000yen, and only 1 order per person.
What do you think are the reasons behind the domestic restriction? No, not the "Johnny hate international fans!" comments. (Don't pull a Tumblr on me.) But it seems their aim definitely isn't Oricon
Edit: It is possible for the CD to be charted should JStorm choose to, according to a comment, but imo breaking records is not the intention.
Edit 2: The CD is specifically to commemorate Arashi's 5th year performing at the National Stadium. (thanks exdream1999 for info)