Magic cards often interact with each other in a linear way — but the power of a card is exponentially related to its mana cost. So, when a card that costs 5 or 6 hits the battlefield, it may change the rules in a way that turns things up a notch. Unfortunately, most formats are too fast for these cards to be primary pieces: by the time you have that much mana, the game is probably either won or lost.

A group of Alaskans came up with a way to slow the game down. By playing a 4-player game where each begins with 40 life, those exponential plays start to matter more than the linear ones. To further draw things out, you only get one copy of each card, and the deck must have exactly 100. But, to have a bit of consistency, one of those cards is a character that you can cast at any time, even if it gets killed, exiled, or evicted in any other fashion.

This character is your general, and he is the commander of your team. You may only use cards that match the color identity of your general, and only legendary creatures can serve this role. The other name, EDH, stands for Elder Dragon Highlander, because initially, only the five Elder Dragon Legends were used as generals. These days, there are enough options that you can use any combination of colors you like. If you choose wisely, the abilities of the general may increase the effectiveness of your cards.

Commander decks have access to nearly any card ever printed, so it’s possible to make extremely powerful decks despite the restrictions on construction. One factor that will rein you in is that there are three other players who can team up if you present an outsized threat. In most cases, you will need to understand the power level of the decks in your playgroup and adjust accordingly. Many players construct two or more decks, so they are prepared for this.

One of the precepts of Commander, albeit one not always exercised, is that the players should pause before the game to discuss what goals they have for the experience. In some environments, you can win prizes for meeting these criteria rather than actually winning the game. One goal is that the game should be fun and no one should feel left out. However, you’re still not allies… the distinct presence of politics and betrayal is one element that makes the format difficult for some.

Another challenge is that with many cards on the battlefield at once, there are lots of triggers that can be easy to miss. For instance, some cards take effect at the beginning of every turn, or whenever a creature enters the battlefield, or whenever one dies. These events are so typical that it’s easy to forget triggers. Other times, the effects of cards combine in ways that are too complex to reason out without referring to an authority. When you have a rules question, it’s best to find the answer before proceeding — you can get a ruling from a judge at http://chat.magicjudges.org or by simply searching for the card or rules text in question. When you play in a public setting, you’ll likely be sitting with someone who has looked up most of those questions already; they’ll advise truthfully because they want their deck to prevail in a fair fight.

Since this format is so popular, it’s easy to find ideas for decks that utilize all the obscure cards from Magic’s 24-year history, and to scour the web for foil or unique editions of those cards. Building a deck sometimes means mail-ordering many individual cards, but if your budget is a factor you’ll still have many, many good options.

Commander matches can take hours to complete, so it’s definitely good manners to finish your own turns quickly. Despite these concerns, the rollercoasters this format creates are unlike anything else in gaming.