The event is a repeat of last month’s, in that you’ll be playing with a “Forbidden Cards are now Limited” event.

To enter the event, you need to buy at least 3 packs of “Collector’s Pack: Senkou no Duelist”, the latest Collector’s Pack (The Japanese version of the Dragons of Legends packs.)

The participation prize is a very special Card Stock Case

Yes, it’s a Stock Case using the art of Duel Monsters era cards from Duel Arena, i.e. The Chibi Arts. Each person gets one upon entering the event and June’s Yu-Gi-Oh! Day will also be handing this out.

Source