Instant Speed

Play Magic long enough, and you'll hear someone mention that a spell or ability can be used at "instant speed." This almost always means that it is an instant spell, activated ability, or spell with 'flash.' This post looks at the value of instant speed.

"Instant speed" cards/spells are valuable because they are the only things that can be played:

1. when one or more spells are on the stack
2. on your opponent's turn

Let's look at each.

1. When spells are on the stack

On your turn, when no spells are on the stack, you can play any type of spell you want: sorcery, instant, creature, enchantment, planeswalker, artifact. You can also play activated abilities. Once you play a spell/ability, an opponent can respond with an 'instant speed' spell/ability of their own, placing it on the stack on top of yours. You can respond to that if you have a remaining 'instant speed' spell/ability. This can continue until all players pass; then, the things on the stack are resolved in priority order, which means from top to bottom. 

Having 'instant speed' cards/abilities is valuable in this scenario. Many types of removal spells work best at instant speed. Some work only that way (like counterspells). 

2. On your opponent's turn

The wise Magic player keeps their opponent guessing. The primary way to do that is by playing spells/abilities at the last possible moment. 'Instant speed' cards/abilities enable this, in part because they can be played on your opponent's turn- if you have the mana.

Let's say you have five lands in play. On your turn, you cast a spell for three mana, leaving two lands untapped. You also have two cards in hand. Now it's your opponent's turn. 

Since you have cards in hand and kept lands untapped for your opponent's turn, and may have abilities on permanents in play you could activate, it forces your opponent to make choices without all the information. They have to think through questions to include:

• "What can he do with [x] untapped lands?" 
• "Should I play my spell[s] and risk removal?" 
• "Should I attack and risk an unexpected/unknown response?" 

And so on. These unknowns enable a major goal: to gain an advantage over your opponent through

• making them hold back attacks or spells for fear of countering/removal
• you may have nothing playable in your hand, but if your opponent doesn't know that, keeping lands free gives you an edge and makes them waste an opportunity
• you may have something very playable in your hand, and if your opponent holds back, it lets you keep that spell for later use (and still makes them waste an opportunity)
• making them waste their resources (mana, spells, or permanents)
• if they play a card and you counter/remove it, they've wasted mana and a spell

All of this is made possible only with spells/abilities playable at instant speed. It makes the opponent think twice, guess, and so on. On the other hand, if they know you can do nothing (because you have no untapped lands, no cards in hand, or no abilities you can use), it gives them free reign to be aggressive or sit back and take control (through saving lands and spells of their own).

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Let's look at an example. Here are two cards from recent sets that do similar things, but one is a sorcery  (playable only on your turn), and the other an instant:

Bankrupt in Blood costs more (in mana and creatures to sacrifice), but you get to draw three cards. But let's ignore that for a second- in fact, let's say it has the exact same cost and benefit as Village Rites, but is still only a sorcery. Village Rites sees a lot of play; Bankrupt in Blood sees next to none. Why? Because of instant speed. A scenario to illustrate my point:

1. You have two creatures on the battlefield, it's your turn, and the stack is empty. You play Bankrupt in Blood. Your opponent plays an instant that destroys one of your creatures. His spell resolves first; when you resolve Bankrupt in Blood, you can no longer pay the additional cost (since you're down to one creature), so the spell is discarded and wasted.
2. You have two creatures on the battlefield, it's your opponent's turn, and the stack is empty. They play an instant that destroys one of your creatures. You respond with an instant of your own- Village Rites- sacrificing the creature your opponent just targeted. Your spell resolves first; you draw two cards and waste your opponent's spell (and mana he spent to cast it). Yes, your creature died, but it would have anyway, and you get two cards out of it.

In essence, 'instant speed' spells/abilities are useful because they are flexible (playable in more situations) and may withhold information from your opponent, forcing them to guess as part of their strategy. Use them where possible.