The official Japanese Pokémon website has announced that players who purchase the Pocket Monsters Black White Official Guide Play Book (ポケットモンスターブラック・ホワイト オフィシャルガイド　通信プレイまるとくブック) for 850 yen will receive a unique serial number in the book to unlock the special Porygon downloads via Pokémon Global Link. The books ISBN number is 978-4-8401-3937-3.

A Porygon-Z C-Gear wallpaper, a Porygon2 decoration for the players Dream House as well as a Porygon that has the ability Analytic are the promotions that are being offered for those that purchase the book. The serial numbers will be good to use from May 18th, 2011 until April 26th, 2012. Our C-Gear page has been updated with the latest information.


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Source: http://www.pokemon-sp.jp/