Sold as an 8cm disc.
Collect all of the remaining discs to complete the "puzzle":
Code:
http://vgmdb.net/album/54351
http://vgmdb.net/album/54372
http://vgmdb.net/album/54374
http://vgmdb.net/album/54376
http://vgmdb.net/album/54378
Sources:
Code:
http://www.usagi.org/doi/sakura/cd/s-all.html
http://www.aic.gr.jp/anime/cc-sakura/cd.shtml
http://www.shop-yamada.com/ab/CDSP-VIDL-30224-9.htm
https://ja.wikipedia.org/wiki/%E3%82%AB%E3%83%BC%E3%83%89%E3%82%AD%E3%83%A3%E3%83%97%E3%82%BF%E3%83%BC%E3%81%95%E3%81%8F%E3%82%89_%E3%82%AD%E3%83%A3%E3%83%A9%E3%82%AF%E3%82%BF%E3%83%BC%E3%82%B7%E3%83%B3%E3%82%B0%E3%83%AB