Book 1

Sep 28, 2007
Japanese
Paperback (436 pages)
Apr 1, 2005
Japanese
Kindle (337 pages)

Book 2

Sep 1, 2007
Japanese
Hardcover (317 pages)

Book 3

Apr 1, 2012
Japanese
Kindle (318 pages)

Book 4

May 22, 2012
Japanese
Kindle (191 pages)