They say that, in life, you tend to get what you pay for.
The Cost of Playing a Spell
Last week, I named mana as one of the basic resources of Magic. Casting a spell requires an investment of mana; you amass the required amount of mana, and then you spend it on a spell.
At the simplest level, you'd expect that the effect of a spell should scale with the amount of mana you spend. If I go to a store and spend $10 on a white T-shirt, I'd expect that I could get two white T-shirts for $20 or five white T-shirts for $50. With that in mind, consider these two cards:
I can spend one mana on a 1/1 creature by putting Charging Badger in my deck, or I can spend two mana on two 1/1 creatures by putting Raise the Alarm in my deck. At first glance, this seems to be fair and makes sense; one card costs half as much as the other and has half the effect. All is right in the world.
However, the reality is much more complex. In fact, Raise the Alarm is quite a good Magic card while Charging Badger is actually quite a weak Magic card. The ratio of mana spent compared to the effect on the board is the same, and Charging Badger even offers trample as a cherry on top. Why is it not that simple?
Well, to cast Charging Badger actually costs much more than half of what it costs to cast Raise the Alarm. It's true that, in terms of mana—one of Magic's basic resources—one card costs twice as much as the other. However, in terms of Magic's other basic resource, the two cost exactly the same amount.
To cast either one costs you one card out of your hand.
You start the game with seven cards in your opening hand, and you get to draw one more each turn. This puts a strict limit on what you have to work with in a game of Magic. If I cast two Charging Badgers and you cast one Raise the Alarm, we've both spent exactly two mana, but you've gotten the better of me. Our spells will trade off and you'll be left with one extra card in your hand, which might help you pull ahead in the game in any number of different ways.
Similarly, if everything was as simple as the ratio of mana cost to impact on the game, then Ornithopter would be one of the best cards in the history of Magic! In this simple world, every deck would want four copies of Ornithopter. In the world we live in, though, most players (rightly) do not choose to play with Ornithopter in their decks, because the cost of one card is too high for the effect of a measly 0/2 creature.
Players who do not treat cards as a resource are likely to be frivolous, squander their spells, and quickly run out of things to do in a game of Magic. They'll soon be at the mercy of the top of their libraries, which is a frightening and unreliable way to play. A player who does treat cards as a valuable resource, on the other hand, will squeeze every bit of value out of every spell, and do everything possible to pull ahead in a game.
Card advantage is, very likely, the single most important concept in competitive Magic. A tremendous proportion of games are decided, in one way or another, by card advantage.
The term is nearly as old as the game itself. One of the founding fathers of Magic writing and theory was Eric Taylor, who defined it like this: "Card advantage is any process by which a player obtains effectively more cards than his opponent."
If that definition seems a bit nebulous, it's because card advantage can take such a tremendous variety of forms. Let's start with a simple one.
Drawing Extra Cards
Here, card advantage is just a simple matter of counting. When you cast Divination, you draw two cards. Don't forget, however, that it costs you a card to play a spell out of your hand. Divination nets you one card. Jace's Ingenuity draws you three cards but costs you one card, netting you two. Both of these spells provide reliable card advantage.
Note that if a spell had no other effect except to draw you one card (such as Reach Through Mists), then it would not provide card advantage. It would draw you one card and cost you one card, with no net gain in card advantage.
Sign in Blood has the same effect as Divination, except that it costs you 2 life. Life, like mana, is a resource in Magic, but it's very hard to make any direct comparison between these different resources. In counting card advantage, you would also say that Sign in Blood nets you one card, and any other consequences of casting the spell would need to be considered separately.
Card advantage is about more than just the number of cards in your hand. Typically, adding a permanent to the board should be counted toward card advantage as well.
Remember the example of the Reach Through Mists, which draws one card? It offers no net change in card advantage; you simply break even. With Shaman of Spring, though, you get to draw a card while also adding a creature to the table. Like Divination, this is a net gain of one card. Think about Runeclaw Bear and Reach Through Mists stapled together, so you get to have both effects while only costing one card out of your hand.
Taking Away Your Opponent's Cards
By definition, the term advantage has to do with your own position relative to your opponent. You can gain card advantage through favorable interactions with your opponent's cards.
You cast Mind Rot and knock two cards out of your opponent's hand. As always, you're down the one card that it cost to cast the spell from your hand. However, your opponent is down two cards for your troubles. Although both of you are technically down on cards, card advantage is relative. Your opponent is down one card more than you are, so you've "gained" one card.
For the purposes of card advantage, attacking your opponent's permanents is the same as attacking his or her cards in hand. When you cast Spiteful Blow, you destroy two permanents. Lands count as cards also! After all, your opponent will need to draw at least two cards before he or she can hope to replace the land and the creature that you destroyed.
You put a card like Cone of Flame into your deck without knowing exactly how many creatures it might kill. You can easily see that it has the potential to kill three, but you won't know for sure what it'll do until you draw it in a particular game. You can count card advantage as it shows up during gameplay exactly the same as I'm counting it with paper and pencil right now. If you kill three creatures with Cone of Flame, you might say, "I cast Cone of Flame as a three-for-one." Imagine your opponent only has one or two creatures for you to kill, and you have to point the extra damage from Cone of Flame at your opponent instead. (Remember, just like Sign in Blood, damage to a player works on a whole other axis, and should not be counted as card advantage). In that case you might say, "I cast Cone of Flame as a one-for-one," or "...as a two-for-one."
Virtual Card Advantage
Counting card advantage in the way described above is simple, it's helpful, and it's good to get into the habit of doing so. Unfortunately, it often doesn't tell the full story of what's going on in a game.
Let's get back to where we started, with the example of Raise the Alarm. In a very strict technical sense, Raise the Alarm adds two creatures to the battlefield, and should therefore be considered two-for-one card advantage. Sure, in the exact case where I attack you with two Charging Badgers and you block with your two Soldier tokens from Raise the Alarm, then it has traded for two of my cards, and it's fair to describe the spell as having provided card advantage.
Both cards put two creatures onto the battlefield, and therefore provide two-for-one card advantage. But how can you account for the fact that I, as your opponent, need only play a 2/2 creature before those Soldier tokens can no longer profitably attack? How can you account for the fact that my Treefolk might be 4/4s, 6/6s, or 20/20s!?
In practice, games of Magic reach a point where some cards are capable of affecting the outcome and some cards are not. At points like this, it can become misleading to continue counting spells like Raise the Alarm (or anything else that's unlikely to change the outcome of the game) as card advantage. Instead, it can be more helpful to consider virtual card advantage, which (while being more difficult to quantify) accounts for the fact that not every Magic card is the same or, for that matter, equal.
Dead Cards and Blanking Cards
Anyone who's ever suffered from a mana flood can tell you that games sometimes reach a point where drawing more land is simply not helpful. Once you have enough mana to do everything you want to do, extra lands can become dead cards—they no longer impact the game at all.
One way to gain virtual card advantage is to blank one or more of your opponent's cards—turn them into dead cards. This might sound like an advanced concept, but I'd venture to guess that everyone reading this has done it before. If you've ever played a big creature to block, then you've blanked your opponent's attackers!
Once you put a Netcaster Spider onto the battlefield, your opponent's 1/1 and 2/2 creatures can no longer profitably attack. That Netcaster Spider can serve to blank essentially any number of small would-be attackers, providing the potential for virtual card advantage.
If your opponent has cards like Thoughtseize or Mind Rot in his or her deck, you can employ a strategy where you play out all of your cards right away and never have anything sitting in your hand. If you do, you've blanked any future discard spells your opponent might draw off the top of his or her library.
Similarly, you can blank cards during deck building. If you're worried about facing the card Naturalize, you can simply build your deck with no artifacts or enchantments. You've suddenly turned that Naturalize into a dead card.
Finding a Use for Dead Cards
On the other hand, you can also earn virtual card advantage by finding a creative use for cards that would otherwise be dead.
Imagine a game that's dragging on and on. Maybe it's gone fifteen turns, maybe it's gone twenty. Neither player can get much benefit from any land beyond the sixth or seventh. However, while Johnny is sitting there getting frustrated with every useless land he's inevitably drawing, Jenny is using her Rummaging Goblin to discard all of her extra lands and low-impact cards, giving her more fuel and digging toward the cards that actually matter.
The Rummaging Goblin has never technically given Jenny card advantage, it's simply changed her old cards into new cards. Nevertheless, it's given her virtual card advantage by turning her otherwise-useless cards into something helpful.
Low-Impact Cards and High-Impact Cards
Often, it only takes a quick glance at a game of Magic to tell that some cards have simply been outclassed. Charging Badger is an example of a card that's very likely to be outclassed, and very unlikely to change the outcome of a game. Charging Badger is a low-impact card. That's why, despite its affordable mana cost, it's often left on the sidelines.
Technically speaking, Raise the Alarm provides a two-for-one advantage. However, if one player casts Raise the Alarm and the other plays Ob Nixilis, Unshackled, who do you think came out on top? Ob Nixilis is an example of a high-impact card. It's the type of card that's very likely to swing the outcome of a game if it goes unanswered. What's more, it happens to be capable of blanking smaller creatures (and any card that would cause your opponent to search his or her library, for that matter).
Putting an emphasis on high-impact cards is one more way to earn virtual card advantage.
It's not always the player who technically earns more card advantage who wins the game. One player might be casting Divinations and Jace's Ingenuities until the cows come home, but if he or she is only drawing into Ornithopters and Charging Badgers, then it might only take one high-impact card like Ob Nixilis on the other side of the table to make it all look silly.
It's important to understand the theory behind card advantage and be able to count card advantage in simple exchanges. However, there are also times when the technical way of looking at things is not enough and you should recognize when virtual card advantage can be just as important.
Competitive Magic often runs on very thin margins, and small sources of card advantage like a two-for-one trade or blanking an opponent's card can easily be the difference between a loss and a win. Card advantage is at the heart of much of the game's strategy and theory. I'll be returning to these concepts often as this column moves forward. For now though, I hope this has served as a helpful introduction—or refresher course—for a very deep concept.