A Boss Duel (ボスデュエル Bosu Dyueru) is a special type of Duel performed in Japan during a Yu-Gi-Oh! Day event. During these Duels, a shop staff member uses a Boss Deck and up to 3 players can challenge that Deck at once. Each Boss Deck is designed as a mock-up of a villain from the anime, with each card based on either an extremely powerful anime-only card or the anime counterpart of a physically existing card.