Changes

* ''[[Yu-Gi-Oh! Duel Monsters Perfect Master BOOK Volume 2]]'', the second game guide for ''[[Yu-Gi-Oh! Duel Monsters (video game)|Yu-Gi-Oh! Duel Monsters]]'', is published in Japan.<ref>{{cite web | url = http://www.amazon.co.jp/dp/4087790126 | title = 遊☆戯☆王デュエルモンスターズパーフェクトマスターBOOK (下巻) (Vジャンプブックス―ゲームシリーズ) [単行本&#93; | trans_title trans-title = Yu-Gi-Oh! Duel Monsters Perfect Master BOOK (Volume 2) (V Jump Books - Game Series) [Paperback&#93; | language = Japanese | publisher = Amazon.co.jp | accessdate = June 27, 2013 }}</ref>

* '''20''' - ''[[The Valuable Book 1]]'' and its [[The Valuable Book 1 promotional cards|promotional cards]] are released in Japan.<ref>{{cite web|url=http://books.shueisha.co.jp/CGI/search/syousai_put.cgi?isbn_cd=4-08-782764-X|title=遊・戯・王　オフィシャルカードゲーム　公式カードカタログ　ザ・ヴァリュアブル・ブック　　1|trans_titletrans-title=Yu-Gi-Oh! Official Card Game Official Card Catalog: The Valuable Book 1|language=Japanese|publisher=[[Shueisha]]|accessdate=January 26, 2013}}</ref>