Timetwister is one of the game’s iconic cards, making up the Power 9 along with Black Lotus, Ancestral Recall, Time Walk, and the five Moxen. These cards are considered to be among the most powerful cards in the game—all are banned in Legacy and restricted in Vintage. Although Timetwister may not be fully deserving of a spot in the Power 9—Sol Ring is arguably more powerful—history has taught us that drawing seven cards for 3 mana is a dangerous effect, especially for Storm-esque combo decks.
In contrast to Timetwister, a sorcery-speed Day’s Undoing ends the turn right away. This means that Day’s Undoing doesn’t help combo decks to go off the turn you cast it. It also means that after refilling both players’ hands, your opponent gets the first shot at benefiting from the seven new cards. This takes out various ways to break the symmetrical effect, but plenty remain.
How to Break the Symmetry?
1. You empty your hand faster than your opponent
For Day’s Undoing to be useful, you need to benefit more from the hand refill than your opponent. If Day’s Undoing is on the stack when you have 2 cards remaining in hand while your opponent has 5, then from a card economy perspective it’s similar to drawing three cards. That’s a fine deal for 3 mana. However, if you have 3 cards remaining to your opponent’s 5, then it is comparable to a Divination with a drawback, which is mediocre. So, you need to empty your hand faster than your opponent. The easiest way to do this is by having a lower mana curve than they do and/or by having a lot of mana acceleration. Cards like Ornithopter and Springleaf Drum come to mind.
2. You are not playing the mirror match
This is a corollary to the first point: In the mirror match, both players’ mana curves are by definition the same, so it will be tough to break the symmetry.
3. You have the luxury to spend 3 mana and a turn on a card draw spell
If you are playing a linear, non-interactive aggro deck (say, Affinity or Burn) and your opponent is piloting a combo deck that aims to race you (say, Bloom Titan or Ad Nauseam), then Day’s Undoing won’t be great. Spending your third turn on an expensive card draw spell rather than creatures or Bolts might turn your turn-4 kill into a turn-5 kill, and you may regret that when your opponent assembles their combo on turn 4. However, if you’re up against midrange/control decks like Jund or Grixis, then things are different. Those kinds of decks play a grindy game with lots of trades, against which a hand refill is more valuable.
4. Your opponent cannot draw cheap hate cards
Modern in particular contains a lot of high-power hate cards, and Day’s Undoing risks giving your opponent one of them. Imagine you’re playing Affinity against a white deck in a post-sideboard game. Your opponent kept a hand without Stony Silence, so you’re doing well early on. You then cast Day’s Undoing and—oops, your opponent drew Stony Silence and beats you with it. This is a risk. It doesn’t apply to hate cards that are more expensive than Day’s Undoing (like Creeping Corrosion or Shatterstorm) because it’s just about as likely for your opponent to shuffle them back as to draw them, but it does apply to cheaper hate cards.
5. Opponents rely on their graveyard
Day’s Undoing shuffles each player’s graveyard into his or her library, so you can use it as graveyard hate. In Standard, Deathmist Raptor and Dig Through Time are examples of graveyard-reliant cards whose effectiveness is reduced by Day’s Undoing. In Modern, Snapcaster Mage, Tarmogoyf, Gurmag Angler, and Goryo’s Vengeance come to mind. Interestingly, state-based effects are checked as the turn ends, so a Tarmogoyf that blocked a Memnite will die after you cast a post-combat Day’s Undoing.
6. You are on the play
Suppose you play a land and a spell on your first two turns, while your opponent only plays a tap-land and passes (or plays spells that don’t affect their hand size, like Serum Visions or Satyr Wayfinder) on their first couple of turns. Then you cast Day’s Undoing on turn 3. If you were on the play, then you’d have three cards remaining to your opponent’s seven—that’s great! If you were on the draw, you’d have 4 cards to your opponent’s 6—much less exiting! So, it might be wise to board in Day’s Undoing on the play and take it out on the draw.
Based on these notions so far, my first idea is to put 2 Day’s Undoing in the sideboard of Modern Affinity and to board it in against Jund or Grixis on the play. This allows you to take advantage of all six previously-described points. But that’s just a first idea. There are still plenty of other ways to break the symmetry, so let’s continue.
7. You cast it on your opponent’s turn
So at the end of your opponent’s turn, you play Quicken followed by Day’s Undoing. This way, you get the first opportunity to benefit from the seven cards. It sounds cute, but it requires an additional mana to implement, and your opponent gets another turn to empty their original hand before receiving the refill. So, I don’t like this very much. If the card simply said “end the turn” then maybe it would be worth going through the effort of ending your opponent’s turn, but unfortunately it doesn’t work like that.
8. You deck contains plenty of instants
If you have plenty of lands on the battlefield, then ending the turn is a huge drawback—unless your deck can operate at instant speed. If you can use some of your excess mana to cast some freshly-drawn instants on your opponent’s turn, then a large part of the drawback is negated. Flash or Aether Vial would work as well. I like this angle more than Quicken.
9. You turn the end-the-turn downside into an advantage
Suppose you go turn-1 Faithless Looting, discarding Griselbrand. At the end of your opponent’s second turn, you return it with Goryo’s Vengeance. Then, on your 3rd turn, you play Day’s Undoing, end the turn, and keep your Griselbrand around! Cheers all around—until your opponent reminds you the exile trigger still happens at the beginning of his next end step. Yeah, that doesn’t really work. So maybe we should play Quicken + Day’s Undoing in response to the Goryo’s Vengeance trigger at the end of our turn? That might work, but we’re going a bit too deep here. A realistic way to capitalize on ending your turn is via Final Fortune, but I’ll leave that to Legacy specialists to shoot down.
10. Combine it with Notion Thief
The difference between drawing 7 and drawing 14 is not that significant because you have to discard down to 7 anyway, but denying any cards to your opponent could be huge. To be fair, if you spend seven mana on a 2-card combo, then you might as well go for Pestermite and Splinter Twin to actually, you know, win the game, but Notion Thief is still a fun card. As a rules note: Notion Thief works because it’s a replacement effect, but triggered abilities, such as the one from Underworld Dreams, won’t help you (as confirmed by rules manager Matt Tabak).
11. You are playing a battlefield-based combo
Card draw is particularly useful in decks that aim to put together some combo. For Day’s Undoing, this has to be a battlefield-based combo (such as Spike Feeder + Archangel of Thune) and not a spell-based combo (such as Angel’s Grace + Ad Nauseam). After all, you want to be able to put one of the pieces on the battlefield before casting Day’s Undoing; you don’t want to shuffle a piece into your library.
12. You combine it with bounce spells
A bounce spell played just before Day’s Undoing effectively becomes a hard removal spell. So the value of cards like Retraction Helix, Sidisi’s Faithful, and Void Snare shoot up in a Day’s Undoing deck.
That’s enough ways to break the symmetry. Now let’s put them in practice. I have both a Modern brew and a Standard brew that aim to take advantage of Day’s Undoing.
Day’s Undoing in Modern
This opening hand is pretty sweet:
Then again, any hand with Mox Opal is sweet. And I’m not even sure that Day’s Undoing is that much better than Master of Etherium in this hand. I mean, it probably is, but Master would set you up for a turn-3 kill, whereas Day’s Undoing doesn’t guarantee that. Overall, I’m skeptical about including Day’s Undoing in the main deck of a regular Affinity decks when the Modern format is dominated by low-curve decks and combo decks. As I mentioned before, boarding it in against Jund or Grixis when you’re on the play is a decent idea, but if you really want to play with Day’s Undoing in the main deck, then I think you need to sculpt the deck around it. How about adding mana acceleration, instant-speed effects, and a combo to the deck? Enter Disciple of the Vault and Aether Vial.
Vial Affinity with Day’s Undoing
A regular Affinity deck doesn’t include Vial because it already contains enough mana acceleration and too few colored creatures, and Disciple doesn’t see play because it requires colored mana and you don’t assemble the Disciple + Ravager pair consistently enough. Day’s Undoing changes all that.
To be fair, my initial feeling is that this build is worse than regular Affinity, but still worth testing. At the least it illustrates that simply tossing in a few copies of Day’s Undoing into an existing deck doesn’t allow you to take full advantage of it—you need to rethink the deck’s foundation completely.
Day’s Undoing in Standard
Let’s start with another sweet opening hand.
So on turn 2, you play Sidisi’s Faithful to bounce your opponent’s Fleecemane Lion and follow it up with Day’s Undoing to refill. Ah, Magical Christmasland. Here’s how a corresponding blue devotion/artifact deck might look:
Mono-Blue Artifact Devotion
Harbinger of the Tides, the 2/2 Merfolk for UU, fits this deck quite well because it can be cast at instant speed (point 8) and bounces (point 12). I also like how Day’s Undoing increases the odds of drawing extra cards with Faerie Miscreant. Nevertheless, you have to jump through a lot of hoops to take advantage of Day’s Undoing in Standard, and I doubt this blue deck will prove to be powerful enough.
My Final Verdict
Day’s Undoing is potentially powerful, but it’s a symmetric effect that benefits your opponent as well and that requires a lot of effort to break. Although I provided plenty ways to break the symmetry, I’m not sure it will find a good home. Nevertheless, the low mana cost is enticing, and it’s certainly worth trying. I know I will.