The current discussions on card advantage seem to be dying down lately. With the lines being drawn, it seems as if people have chosen their point of view and refuse to budge (myself included). For better or worse, individual's theories on card advantage will either help or hinder them in the arena of competitive Magic. Others see the resolution of this topic as a godsend."Not another article on card advantage" has become a common response in the forums.

I have decided to take this development as an opportunity to start up a discussion on the other fundamental concept behind Magic, tempo. Up until this point, it has been vaguely defined. EDT wrote"Time is for the most part interchangeable with mana." Most players have some concept of what tempo is. When your opponent has three Jackal Pups out on turn 2 and you are still waiting to get that sixth mana to cast your Craw Wurm, your loss is inevitable. I will use this article as an attempt to describe some aspects of tempo in a more concrete way than what has been written before. Tempo, much like card advantage, wins games.

The first thing that Magic players should realize is that tempo is not a Magic term. It is a term that developed out of chess analysis. Considering that chess analysis has been around for well over one hundred years, it will beneficial to point out what more advanced analysts than myself have written about tempo.

From http://www.eudesign.com/chessops/basics/cpr-temp.htm:

"In chess, a"tempo" is a gain in time-units (represented by moves). When one player gains a tempo, it effectively means that his opponent has been forced to waste one or more moves."

From http://chess.about.com/library/glossary/bldeftem.htm:

"A single move in chess by one player, also known as a 'half-move'. Since the players move in turn, the term is normally used to count how many moves one of the players takes to perform a specific maneuver. The loss of a tempo, where a player takes two moves to accomplish what can be done in one move (or takes three moves where two moves are enough, etc.), can be sufficient for a decisive advantage.

In chess, tempo represents moves. Since you are limited to one move a turn, tempo is gained by forcing your opponent to take back moves, essentially giving yourself a free turn. In Magic, the idea is slightly different but transfers over almost entirely intact. The difference between the two games is that in Magic you are allowed as many"moves" or plays as your mana base permits.

The rest of this article rests on three concepts of Magic, all leading to the number of plays you can make in one turn. Casting cost, mana base, and card advantage. The basic idea being that the number of plays you can make between untap steps (a turn) equals the number of mana you can produce, divided by the casting cost of your spells. As we can see, lower casting cost spells and large amounts of mana increase this ratio.

Casting Cost
It is generally accepted that lower casting costs are better. Not only does this prevent you from getting"mana screwed," but it increases the chance that you will be the first player who is able to cast more than one spell a turn. The trade off that players must decide between is that Wizards has a general plan in place to cost spells according to their power level. Generally speaking, the more powerful the card, the higher its casting cost.

However, casting cost is not a direct way to calculate tempo. Some authors have claimed that casting Terror on an Exalted Angel gains that player tempo. This is simply not true. Casting Terror on Exalted Angel simply gains that player the opportunity to gain tempo. Consider the following two examples:

Both players have six mana sources.

Example #1
Player A hard casts Exalted Angel. On the following turn, player B plays a main phase Terror targeting Exalted Angel. Player B then proceeds to pass the turn with no instants in hand.

Each player has made one play. Much like trading one for one card advantage, there is a parity in this line of play. (more on this later)

Example #2
Player A hard casts Exalted Angel. On the following turn, player B plays a main phase Terror. This time he follows it up by playing Ravenous Baloth.

Player A has made one play to player B's two plays. Due to the cheaper casting costs of player B's spells, player B has gained a tempo advantage of one play.

This kind of tempo gain is most commonly seen in an Aggro vs. Control matchup (the classic battle of tempo vs. card advantage). The aggro player wins simply by overrunning the control player's counterspells. This occurs due to the extremely cheap casting costs of the Aggro player's spells

Mana Base
The other half of the equation. The more mana a player can bring into play, the sooner they can gain a tempo advantage. Most games of Magic will see each player develop their mana base at the same speed, one land per turn. Barring mana screw, this is a fair way to allow each player gain an equal amount of tempo and make for an even match.

The only way a player can increase this half of the equation is by playing mana acceleration. Most players get their first taste of tempo while playing with cards like Birds of Paradise, or Llanowar Elves. These two cards represent cheap efficient ways to increase the player's"1 mana source per turn" limit. Gaining an advantage through mana acceleration quickly leads to a gain in tempo on the other player.

The following examples illustrate how developing you mana base is not a direct indication of tempo, but leads to a tempo advantage (plays/turn):

Example #1
Player A has just started a game of Magic. The two cheapest cards in hand are Birds of Paradise and Call of the Herd. Play develops quite naturally by a turn 1 Birds of Paradise, followed by a turn 2 Call of the Herd.

Number of turn 2 plays without Birds of Paradise: 0

Number of turn 2 plays with Birds of Paradise: 1

As we can see that by developing their mana base with Birds of Paradise, Player A has gained a tempo of 1 play. Effectively accelerating their development by one turn.

Example #2
Player A has just started a game of Magic, and has kept a hand of Birds of Paradise, Wild Mongrel, and Circular Logic. Player A being on the play, plays a first turn Birds of Paradise. Player B, playing a slower deck, has no first turn play and passes the turn. Now Player A has an opportunity to set up an even bigger tempo gain, and we see the true power of the madness mechanic.

Player A's second turn consists of casting the Wild Mongrel and passing the turn. This reduces the casting cost of Circular Logic, and increases the number of plays from one to two. This tempo was gained off of Birds of Paradise and the madness mechanic. On turn 2 Player B attempts to cast Smother on the Wild Mongrel, which is promptly countered by Player A's Circular Logic. [Assuming that Player A discarded something to the graveyard first. - Knut] We can see that Player A has gained a free play over Player B and prevented the Smother from negating the board advantage gained by Wild Mongrel.

Not only was this two plays to one, Player A's play should not have happened until at least turn 5 (counting Wild Mongrel as a 2/2 for two mana, and Circular Logic is technically costed at three mana), so this line of play was accelerated by three whole turns! Cards have been banned for less (Dark Ritual and Ancient Tomb come to mind).

Card Advantage
Not only are card advantage and tempo the two most fundamental aspects of Magic, tempo is a concept that follows in part directly from card advantage. Whereas early game tempo is more dependant on the casting cost/mana base ratio, late game tempo is determined almost strictly by the player's ability to draw cards.

Without any ability to draw extra cards, there comes a point in a game of Magic where a player will have a maximum tempo of one play per turn. Often referred to as"top deck mode," this effect puts the player at the mercy of lady luck. The most common way to negate this effect is to play some kind of card drawing, allowing the player to"gas up" and keep up with, or exceed the number of plays being made by their opponent.

The other type of card advantage that occurs when one player's cards interacts with another's provides a special case of tempo gain. The card Wrath of God typifies these kinds of plays. Wrath of God not only provides card advantage, but also provides the player with a type of tempo advantage usually on the same order of magnitude. For an example we look at the following plays:

Not only has Player A gained a three-for-one card advantage from Wrath of God, but a three-for-one play advantage has also occurred. Much like Player A is up two cards, Player A is also up by two plays. In fact, it is as if Player A got to cast Peek, Compulsion, and Thirst for Knowledge before Player B even got to start the game. Considering the number of cards and plays Player B is down, it is very unlikely that Player B will win.

Conclusion
As we can see tempo can almost always be described in terms of"number of plays/turn." This simple definition covers most of what players have considered to be tempo. Having said that, I do not believe that there are no other types of tempo that could be discussed. For example, this system does not take into account the types of plays that are represented by combat. A discussion on abilities like haste and how they impact combat is another article in its own right. I think this article is a good first step in coming to a better definition of tempo, and will be a help to many players.