VOILI VOILA
Deck Construction Rules
Players must choose a legendary creature as the "Commander" for their deck. Details
A card's colour identity is its colour plus the colour of any mana symbols in the card's rules text. A card's colour identity is established before the game begins, and cannot be changed by game effects.
The Commander's colour identity restricts what cards may appear in the deck. Details
An Example of what cards are/aren't allowed in a three colour deck.
A deck may not generate mana outside its colours. If an effect would generate mana of an illegal colour, it generates colourless mana instead.
A Commander deck must contain exactly 100 cards, including the Commander.
With the exception of basic lands, no two cards in the deck may have the same english name.
Commander is played with vintage legal cards, with some exceptions:
cards are legal as of their set's prerelease
Shahrazad is legal for play in EDH
The following is the official banned list for commander games. These cards (and others like them) should not be played without prior agreement from the other players in the game.
Ancestral Recall
Balance
Biorhythm
Black Lotus
Coalition Victory
Channel
Emrakul, the Aeons Torn
Fastbond
Gifts Ungiven
Kokusho, the Evening Star
Karakas
Library of Alexandria
Limited Resources
Lion's Eye Diamond
Metalworker
Mox Sapphire, Ruby, Pearl, Emerald and Jet
Painter's Servant
Panoptic Mirror
Protean Hulk
Recurring Nightmare
Staff of Domination
Sway of the Stars
Time Vault
Time Walk
Tinker
Tolarian Academy
Upheaval
Yawgmoth's Bargain
Additionally the following legends may not be used as a Commander:
Braids, Cabal Minion
Rofellos, Llanowar Emissary