Inevitability is the strategic consideration that, all things being equal, one deck will beat another given enough time. This may be a result of a specific card in the deck or hand relative to the board state (as was the case above), the board itself (our boards are otherwise equal but I have an Archivist in play) or the general matchup between two decks (the way that a control deck will naturally have an advantage over an aggro deck in the late game). The onus to end the game is on the player without inevitability. The more turns that pass, in general, the less likely they are to win.
As Ben Rubin pointed out earlier on, most games of Magic are comparable to either a race or a battle of attrition. "In a race, I am trying to implement my plan (my combo, my 20 points of damage, my lock, my unstoppable creature, whatever), before you get yours. In an attrition game, we are trading threats and answers (your Grizzly Bears, my Shock; my Stupor, your Mana Leak; your Disintegrate, my Healing Salve) down to the point where one of us is pretty powerless (often because all of our threats have been killed and we don't have a good way to find new ones) and the other is left to sail smoothly."
It is important to note another possible outcome of the battle of attrition: parity. The most dangerous threats are neutralized with carefully rationed removal, but the mid-level threats keep each other in check and gum up the board. For example, if I have three Foot Soldiers in play, and you have three Foot Soldiers in play, neither player has an advantageous attack. This is true even if one player has a removal spell. My threats are answering yours, and vice versa, and barring a cascade of removal, the game will be decided by a higher tier of threats (evasion creatures, bombs, decking). Parity occurs more regularly in Limited than it does in Constructed. Races tend to be over more quickly than attrition battles—and especially the attrition battles that segue to parity.
The player without inevitability is inclined to push the game toward a race, where the player with it is inclined to push the game toward attrition and parity.
It's important to realize that inevitability is a consideration that is balanced against the current game state.
If you have two Wind Drakes against your opponent's one Grizzly Bears, with both players at 12, then despite any number of bombs in your deck, you might be inclined to just go for it. If you wait, you may draw lands for a few turns, or your opponent might hit a rush of spells, or might even turn out to have a game-breaker of his own you hadn't accounted for. If you're at 20, you would be even more inclined to enter this favorable race. At 6 life, you would certainly want to leave a Wind Drake back. But if your opponent is the one with heaps of bombs in their deck (or even just Spiders you have a tough time answering), you'd probably want to attack, even at just 6 life.
The player with inevitability has an advantage not because defending (i.e., blocking) is a more advantageous position than offending (i.e., attacking), (although this is generally true) but because they have the ability to choose between whichever position suits the occasion best.
Inevitability must be somewhat practical. (For example, the player with the 200 card deck might have natural inevitability; you'll deck first, but this will rarely occur, and more pronounced themes of inevitability are worth addressing.)
Let's look at the changing stages of inevitability, and how they affect game play decisions.
1. Before the Game Starts
Some deck types (and even colors) naturally have more inevitability than others. Aggro decks disregard inevitability in favor of a powerful early game. Control decks function on the basis of inevitability. Combo decks can sometimes have even more inevitability than a control deck, but usually fall between aggro and control and vary depending on the deck.
If you're playing aggro and your opponent is playing control, they have inevitability, unless you have some drastic and powerful deckbuilding inclusions.
If you're playing control against control, inevitability becomes a key issue. Does one player have a single card or certain strategy that overrides the other player's? Because these decks tend to take so long to kill, issues of inevitability have plenty of time to play out.
In control against combo, inevitability is also critical. Because both players' threats are so indirect, games may take a long time to play out. If one player has a strategy that ultimately will trump the others, this puts them at a heavy advantage. For example, if the combo player has a Gigadrowse the control player can't answer (which will tap out the control player, allowing the combo player to "go off"), the control player must somehow find a way to win the game quickly. If the control player doesn't face any trump cards, and his advantage increases as the game goes on, the combo player must find the earliest possible window to try and win.
These notes have implications for deckbuilding.
An aggro deck will be hard pressed to steal inevitability from a control deck. Playing inevitability-related cards in the maindeck, or even the sideboard, is probably a poor strategy. (Unless they are bona fide trump cards.)
Example: My Goblins deck isn’t going to be able to beat a control deck just by boarding in Jayemdae Tome. Their inevitability is much stronger, and my deck isn’t designed to play an inevitability game. (Most of my cards are designed for a race.) I’m usually better off playing cards that help me race better rather than cards that let me try to compete in a slow attrition game.
Inevitability is a factor in aggro-on-aggro matchups, but less than you might think. Both of decks are aimed at ending the game quickly. Games just don’t go as long as they would in control mirrors. In a control mirror, playing Demonfire on the opposing player for 20 might be a valid strategy! In the aggro mirror, a more short-term approach to inevitability must be considered.
Another thing to consider here is that, since aggro decks are naturally designed to race, the best inevitability “trump” cards should also function as aggressive (racing) cards.
Example: When I’m playing my Goblins and Burn deck against yours, Bottle Gnomes might be profitable, but it doesn’t offer me much in the way of either aggression or inevitability. Jayemdae Tome offers inevitability but doesn’t seem to help my aggressive draws much (it forces me to wait). Rathi Dragon is a trump spell and is also good when I’m in a position to race!
- Because control-on-control matchups are so inevitability-involved, it may be profitable to play a trump-spell main deck. After sideboarding, long-term strategies are key considerations. Sometimes control decks become so warped after sideboarding in the mirror (e.g., all creature-removal spells swapped out), that a surprise racing strategy (bringing in a few big creatures) provides inevitability.
- In combo against control matchups it may be unclear who has inevitability during actual gameplay. Including a strong trump strategy in deckbuilding will inform how you play during the game.
Example: The board is even and we both have seven cards, but since I know I have a Gigadrowse in my deck that I don’t think you can beat, I’ll wait to make my move.
A Note on Limited
While decktypes are more defined in Constructed, Limited decks can lean one way or another.
If a Limited deck already has strong sense of inevitability (for example, lots of big late-game creatures, card-drawing engines, mana-sinks, etc), then it's best to make sure it can survive the early game, because victory in the late game is already a likely possibility. Even playing a cheap trashy creature that can chump block might be worth it in some cases!
If a Limited deck has a weak sense of inevitability (for example, mostly cheap and small creatures, few game-breaking spells), it may be worth trying to shore it up. For example, including a few Demoralizes could provide a possible late-game contingency plan.
2. Opening Hand and Early Game
Despite a deck's leanings, a specific opening hand or start to the game can shift either who has inevitability, or the specific relevance of inevitability. It is important to re-evaluate inevitability's strategic implications based on the specific situation.
Your opening hand might provide your blue-white control Draft deck with an aggressive draw but not much mana. Here you would be inclined to race before your lack of mana becomes a crippling disadvantage.
Perhaps your opponent will mulligan several times. In this case, even if your deck doesn't have the strongest sense of inevitability, it may be best to engage in a war of attrition, since you're starting with a considerable bonus, and since it might be safer than risking a race.
Perhaps your opening hand will contain a card that informs a game's sense of inevitability. For example, if your opening hand contains Honden of Seeing Winds, you will be inclined to slow the game down to capitalize off its long-term potential.
Or it might contain Searing Flesh or Demoralize. Sometimes cards require certain qualifying events to happen before they become sources of inevitability. Having a card like Searing Flesh inclines you to race your opponent down to 7, but then hold parity until you reach seven land!
3. Mid to Late Game
Once a game settles down, the significance of inevitability depends on several specific factors.
Life totals: The higher your life, and the lower your opponent's, the more incentive there is to race rather than wait. The reverse is also true in this case (and all subsequent ones).
Other resources: If your opponent is much lower on resources (few cards in hand, few lands in play), you have the option of finishing them off for good if it's convenient (and if it's a resource deficiency they can possibly recover from), or extending the game to maximize this advantage (typically if it's a resource deficiency that has long term implications).
Degree of trump: If the card (or effect—e.g., next upkeep's Prodigal Pyromancer ping) you're waiting for is a definite victory, you will be more inclined to avoid risky racing than if it just provides an advantage.
Wait until trump: The distance until the inevitable victory occurs is important. If it's likely to be soon, I'm more inclined to wait. If it's distant, with much possibility for contingency along the way, I'm more inclined to race.
Example: You're at 4 and your opponent is at 4. You have an Aven Flock and your opponent has a Grizzly Bears. With two cards in my deck, one of which is a Blaze, I'm more inclined to play it safe. With twenty cards in the deck, one of which is a Blaze, I'm more inclined to attack.
Risk: If a race is particularly low-risk, it is more attractive than one that is high-risk.
Example: You're at 4 and your opponent is at 4. You have an Aven Flock and your opponent has Grizzly Bears. You know your opponent's deck contains several Giant Growth effects. In this case, you have additional incentive to avoid a race.
That's it for now. I hope to have opened your eyes to some of the ways that a long-term advantage informs short-term decisions.