Type 4

Type 4 (sometimes stylized as Type4; also known as DC10 and Limited Infinity ) is a casual, oftentimes multiplayer variant format of Magic: the Gathering play, developed originally in the late 1990s by players at "The Comic Shop" in Fairbanks Alaska. The format is often played with decks drafted from a pool of cards pre-constructed for this purpose (similar to Cube Draft), though variations to this rule are not uncommon. Gameplay is defined by each player having access to unlimited quantities of mana at all times, but being restricted to casting only one spell on each turn.

Format Rules
The most basic rules of the Type 4 format are commonly accepted as follows:
 * Unlimited quantities of mana - Each player has access to an arbitrarily large quantity of mana at all times. Sometimes this is interpreted as each player controlling an infinite number of indestructible, shrouded basic lands, which would affect any cards which reference a player controlling these basic lands.
 * One spell limit on each turn - A player can only cast one spell on each turn, as if an Arcane Laboratory were in play at all times. A player can play one spell on their own turn, as well as a spell during each opponents' turn as long as they would normally be able to do so.

These basic rules can be interpreted and modified in a variety of ways. One of the most common variations to these basic tenets, is the concept that any card cast through a cost outside of the usual casting cost in the top-right corner of the card will not count as your spell for the turn. This makes cards such as Force of Will extremely strong, as it allows you to counter an opponents' spell, even after playing one of your own that turn.

Stack Construction
The pool of cards used to play Type 4 are usually pre-constructed by the player to encourage their preferred type of gameplay. Most cards containing an in the casting cost (such as Fireball) are purposefully excluded from this card pool for power-level reasons. Many cards which are excluded from constructed formats due to exorbitantly high mana costs (even from "slower" formats such as Commander) are utilized in the construction of the Type 4 card pool. Cards which allow players to utilize spells on opponents' turns (such as Vedalken Orrery) are also quite valuable to players. Most often, the card pool assembled for Type 4 play is singleton, meaning there are no more than one copy of each card present in the pool. Cards are often pooled from all Magic expansions, including silver-bordered sets.

Game Preparation
Most commonly, the Type 4 card pool is drafted by each player prior to gameplay. This process includes separating the Type 4 stack into individual "packs" of 15 cards, with each player receiving 3 of these "packs". These "packs" are then drafted through a Rochester-style draft. All cards which a player drafts are then included in their deck for gameplay.

Common alternatives to the "Rochester draft" include traditional drafting, random assignment of a 40 card deck from the Type 4 card pool, or all players using the Type 4 card pool as a shared library.

Gameplay
Players begin the game with 20 life and a starting hand of 5 cards. Like in the Commander format, in a multiplayer game, the first player in the game draws a card on their first turn, and turn order proceeds clockwise around the table. Each player draws one card during the draw step of their turn, and phases of the turn follow the normal turn structure for Magic. If a player has more than 7 cards in their hand during their discard step of the cleanup phase, they must discard cards from their hand until they reach 7 cards.

Play during a game of Type 4 proceeds with "chaos" rules - this is to say that there are no restrictions on who a player is able to attack with their creatures or target with their spells.

Gameplay typically favors the "defensive" player when iterations of infinity are in opposition to one another. For example, if a creature with a Firebreathing ability is blocked by a creature which can increase its toughness comparably (such as Crowd Favorites), the blocking creature will survive. Accordingly, if a player can activate an ability on a card without tapping (such as Plaguebearer) it can be countered indefinitely through means such as the second ability of Azorius Guildmage.

A player will win the game of Type 4 by being the "last man standing", either by eliminating all opponents, or by winning through alternate means. All win conditions usually seen in Magic gameplay are also valid here. Damage, poison, and mill are all viable win-conditions. Cards which state that a player "loses the game" (such as Door to Nothingness</c>) or that a player "wins the game" (such as Barren Glory</c>) are also valid win conditions.