and its Role in Cube Design
By TakeABow
I initially posted this as a thread in the cube forum, but here it is again, along with my follow-up comments. Enjoy.
What is the "Critical Turn"?
In most games of Magic the Gathering, there is a particular turn of events which essentially decide the outcome of the game. More often than not, this occurs quite early, between turn 2 and 5. We call this turn where the game is usually decided the 'Critical Turn'. It represents a few things:
1. The turn in which the fastest deck(s) in the format can reach critical mass and become unstoppable
2. The turn in which slower decks must absolutely disrupt the faster decks by or they will lose
3. The turn after which the game is mathematically decided based on board position and potential threats the majority of the time. (Aggro has landed its threats and sealed the game with disruption, or Control has begun to stabilize, etc.)
Play enough games in a particular format and it becomes apparent how far into games they are usually decided. The critical turn varies format to format, due to differences in card power and deckbuilding restrictions. In Vintage, the critical turn is about 2-2.5. In Legacy: 3-3.5. Standard fluctuates wildly due to the varying size of the cardpool, but typically hovers between 3 and 5. Extended will likely fall about a half-turn faster than standard most of the time.
What does this mean for cubes?
Lets look at an example from a cube game I played the other night. Below is the board position at the end of the my third turn. (I'm the red player)
The blue player is at 14 life (4 from the Jackal Pup, and 2 from the Blood Knight), and is facing down a bad situation; 5 power worth of enemy creatures and he can only untap one land a turn because of Winter Orb. The Blue player's growth is shut down and my threats are in place. And if he cannot remove Magus of the Scroll, it has the potential to do some serious long term damage even if the blue player finds and plays some blockers. But this game is not yet decided.
In my cube, the critical turn is right about 3-3.5 (The .5 means that many games are decided by the end of the 4th turn taken by the player who went first (or the 7th turn overall). The situation we just took a look at (If the gamestate at hand were on the critical turn) would be turn 2.5. Lets see what happens next. The blue player untaps one of his islands, draws, lays a mountain, and plays
Both decks had to make critical plays to determine the outcome of that game. If the blue-red player didn't have the pyroclasm to answer my threats right when he did, the game would have likely been over for him. On the flip side of that is the fact that I played Sulfuric Vortex on my 4th turn to seal the game, and without that play, I would likely lose, having expended nearly all my resources for a measly 6 damage.
Generally, I would expect most aggro-supporting powered cubes to play with critical turns right around 3.5-4.5, and unpowered cubes to land in the 4-5.5 range. Many of the cards that enable both control and aggro cost 4 mana, including Armageddon, Nether Void, Jace, the Mind Sculptor, and Wrath of God
So how do we apply this knowledge to Cube Design?
Cube designers are the architects of how their cubes play out. We choose what cards are in and out, and subsequently, we determine exactly where the critical turn lands by our card choices. The leaner the mana curve is, the faster the cube will be, lowering the critical turn. Powered cubes tend to be a bit faster due to the impact of fast mana like Black Lotus, Mana Vault, the Moxes, and cards that facilitate enormous card advantage such as Library of Alexandria or Ancestral Recall.
What cards have the biggest impact on the critical turn?
Cards that can cause huge tempo swings or create lots of card advantage. Including many of the most efficient cards of both types will lower the critical turn. Wrath of God is a full turn faster than something like Hallowed Burial.
The critical turn is often marked by the turn in which both players have managed to play match relevant spells on each of their previous turns, and often the turn before that as well. What I mean by this is that if the critical turn is turn 3, then you would expect both players to have important 2 drops in nearly every game. If it is difficult for both players to land relevant spells until turn 3, then the critical turn will likely be right around turn 4. This is a product of mana curves. Every cube has a particular mana curve, which drives how easily it is for players to play spells at various stages of the game (obviously players can influence this by which spells they draft, but were are speaking in general, so on-average we can analyze the whole cube for this).
The exact implications of mana curves are different from cube to cube, but a couple general rules can help you 'tune' your cube to make the critical turn land where you want it to. Additionally, you may find some colors to be more powerful than others, and often this can be corrected (at least in part) by adjusting the mana curve to make the less powerful color a bit faster.
1) If you want your cube to be faster, decrease the number of 5+ drops and increase the number of 2 drops. This is especially important for powered cubes that wish to enable aggro sufficiently.
2) Keep your 4 drops in check. There is a plethora of excellent cards that cost 4 mana which are are game-changing. It is easy to let the number of 4 drops get too high due to how much better they tend to be than the 3 drops in almost every color. If too many of the game-changing effects are 4-drops, you can expect the critical turn to depend on those cards resolving, which can lead to many games where nothing really happens until turn 4-5 when players start slinging the 4 drops back and forth.
3) Sometimes the mana curve is already quite good, but it feels like something is missing. Maybe a color is underdrafted week after week, and only ever features as a splash. This might be because too many of the cards that could be played on or before the critical turn are utility cards like removal. Sometimes there are very powerful and interesting effects in a color (Cards like Wildfire or Upheaval come to mind) that are quite expensive. If the critical turn is sufficiently below the casting cost of these interesting cards, they will get much less effective use since games will be decided before they get a chance to be played. A solution might be to replace some of the expensive 'interesting' cards with cheaper cards that are more game-changing. An example of this might be including Nature's Claim, Naturalize, Krosan Grip, and Creeping Mold in the cube, as well as Deranged Hermit. A fix might be to swap Naturalize out for an interesting and powerful CMC=2 card such as Sylvan Library and replace Deranged Hermit with Indrik Stomphowler. What this does is keep the number of "destroy an artifact or enchantment" effects the same (after all, you may have spent years tuning the ratios of these effects and don't want to change them), but you added an incentive to play green cards early because sylvan library is so strong. It is a powerful effect that will get drafted highly, see play in nearly every game it is drawn in, and draw drafters and deckbuilders into green. You kept the mana curve the same, but because the effect of Sylvan Library is so powerful, green's critical turn has decreased slightly, hopefully bringing it closer to in-line with the other colors.
Some Example Mana Curves
Here are the mana curves (overall) for the three 405 card cubes that I interact with the most. My cube is represented by the blue bars, and has critical turn around 3-3.5, our "Johnny' Cube is the Red one and has critical turn about a full turn later, 4-4.5, and our Ravnica-Time Spiral Block cube is the green bars and it plays with critical turn 5-5.5 or so.
I would take these plots with a grain of salt because every cube is different, and depends heavily on the individual card choices, but here they are for reference if anyone wants to use the numbers here as a guide.
The Average converted mana costs for the three cubes (Blue, Red, Green) are: 2.81, 3.13, and 3.35
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Follow up remarks
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I will start by pointing out that this assessment is best done when describing high-level play (That is, all decks are competitive with each other - or at least that is the goal). I don't mean that any pile of cards is going to be competitive, but that well-built decks in the hands of good players are going to play well with each other.
That said;
In many limited (and by extension cube) games of Magic, both players basically 'sit around' waiting for a bomb to win the game for them. If a deck like that wins in my cube, I feel as though I have done it wrong. We have answers and more answers, and everything is fast and efficient. Quite frankly, I think the only way to win via a huge bomb is usually to have enough control of either tempo or card advantage to make it to the point in the game where any threat of significant quality will be enough to win.
The critical turn is easiest to spot in the Control vs. Aggro matchup, which is why I used it as the example in the article. But it applies to almost every matchup, including mirrors. The critical turn isn't always the same turn either, sometimes it is turn 2, sometimes turn 5, depending on the draws, the matchup, etc. I say 'critical turn for the cube' to represent the average critical turn across all games played by all quality decks against all other quality decks in the cube, and I am not so brazen as to say that I have nailed it down to be an exact number. My best guess for my powered cube is 3-3.5, based on hundreds of games and our impressions of them as a playgroup. What I'm really trying to elucidate here is not what 'always happens' but what 'usually happens'.
The most important turn in the control vs. control mirror is often the turn in which an important land drop is missed. Or it could be the turn that scroll rack was disenchanted by the opponent. Or when that disenchant was countered. Or Jace was played. Or EoTFoF occured. It is usually difficult to truly determine the critical turn of a long game where decks struggle to reach critical mass the fastest because what actually sent the game along its course was a tiny play.
"Blow-for-Blow" situations are usually the result of both players having multiple quality threats/answers for several turns running, which is often the case in midrange decks, just due to card quality. When these occur, usually the first turn of exchanges is going to be the critical turn. That first creature/removal spell in the chain is often the first move in a larger plan, put into action on the critical turn. Like a gambit in chess, where one player makes a move to prompt the other player into a move, and follows through with a sequence of action/reaction/re-reaction/etc. until the 'knockout punch' can be delivered. However, in a game of magic, the pieces are hidden and it is much harder to clearly divine what exactly is happening. Not to mention that the opponent is also busy enacting his own secret plan at the same time.
If you disagree with the concept of a critical turn, go ahead and ignore it. You're cube has been working just fine without it. But I maintain that it is an important aspect of the design of the cube, and an intrinsic property of the cards put in it, and shouldn't be overlooked.
As for the brainstorm play;
He was sitting on Jace 2.0, Disk, and some other quality cards that he wanted to ramp into and knew he could fix his mana with brainstorm and impulse if he had to. Impulse would let him put a card or two he didn't want on the bottom, and he knew he had 3 fetchlands left in the deck which brainstorm could draw into and allow for a 'shuffle away' of an unwanted card. When winter orb hit, he had only a few outs, and wouldn't be able to get any of his in-hand effects online fast enough to stabilize, so he used impulse to dig, and nearly stole the game because of it.
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My Cube, for reference, can be found here.