Sealed Play

Sealed deck
Sealed Deck is a gametype used in contests that involves limiting the tools and powers available to each player in a controlled fashion. In theory, this forces players onto a level playing field in which no one has a particular advantage or disadvantage over the other; the game play and style of each will be affected by the limits built in to the Sealed Deck. The name derives from sealing an actual deck of cards before beginning a game, e.g. for Magic: The Gathering.

In Guild Wars, a Sealed Deck variant is used in the Codex Arena, which limits the skills available to each player. Each player is allowed to create any build for their profession within those limits; teams can be formed within those limitations.

Guild Wars also offers a Sealed play competition with rules posted on the official site]. Currently, no tournaments are running that uses this format.