Day and Night in Innistrad

 When it comes to MTG, I'm undeniably old school, even if I was literally in elementary school when I was old school, and I had a child's understanding of the game (wait, so we're not supposed to just use every card we own?) I still think of Planeswalker cards as "that new thing" even though they've been around since 2007 (though holy crap do I hope we get a black-bordered Urza planeswalker card in The Brothers War, maybe marking the moment he ascended).

Anyway, many, many things have changed about the game since I started playing. Like, Legend is no longer a creature type, and basic lands actually say "basic" on their type line. Creature spells aren't "Summon *creature type,*" and interrupts haven't been a thing for a long time.

One of the things I find really interesting is that there are these effects that no longer can be determined purely by what cards are in play (or "on the battlefield," which is a new term by my standards.)

Obviously, there have been cards that have effects while in the graveyard, or even while in exile (new term, once again) but I guess what I'm talking about might have started with "The City's Blessing" in Ixalan. This was a threshold (though not Threshold) where, once a player had amassed ten permanents, they got this blessing for the rest of the game, even if they lost some of those permanents. Naturally, like with most stuff in Magic, the "blessing" had no inherent rules - it's a tag that other cards check for.

Still, it's this odd thing: in formats and with decks that don't care about the City's Blessing, this is essentially a rule you can totally ignore. But should any card in your deck refer to it, suddenly it is a thing that needs to be checked.

Perhaps the most ambitious of these odd mechanics is Venture into the Dungeon. In the most recent standard set, Adventures in the Forgotten Realms, this one keyword (well, key-phrase might be a better term for it) carries a massive amount of meaning. It contains all three of the dungeons you can choose from, and requires you to track your progress along them, and then also requires that you track if you've completed a dungeon (and with one card, whether you've specifically completed the Tomb of Annihilation).

AFR boosters, I believe, all come with the three dungeon cards to make sure that everyone has access to them, but it does mean that any deck with this mechanic is going to need to have some way of know all the myriad things that any given instance of this keyword is going to mean.

So, in fact, the codification of "Day" and "Night" in Innistrad: Midnight Hunt, is less complex.

The mechanic is a keyworded version of the traditional Innistrad werewolf mechanic. To explain, werewolves typically enter the battlefield in their human forms. Then, there is a triggered ability, where at the start of the turn, if the player whose turn it was did not play a spell that turn, the werewolves transform, typically becoming bigger and beefier. Then, if someone plays two spells on their turn, the werewolves transform into their weaker, human forms. The idea here is to create a sense of anxiety and dread - your opponent wants to keep playing spells to keep them from transforming, because they become a bigger threat and are harder to kind of stuff back into their human forms once they're out.

Midnight Hunt is going to turn this into a keyword, and creates a new kind of gamestate where it can be day or night, all based on the same spellcasting premise as the older werewolf cards. Then, werewolves simply have the "Daybound" and "Nightbound" keywords on either side of them, transforming when the time changes.

Notably, though, if there aren't any cards that mention day or night, it is neither. Some other cards will actually make it one or the other when they enter the battlefield, and the Daybound/Nightbound permanents will cause the game to start checking if it's one or the other each turn.

I think what's really exciting about this is that Innistrad Werewolves can now be far more complex creatures. The "werewolf mechanic" rules text took up a lot of space, meaning that most in earlier sets could only be kind of "french vanilla" levels of complexity beyond their transformation. Now, you're going to see some far more interesting effects on these lycanthropes.

The establishment of day and night, and Daybound and Nightbound, then also opens up this concept to non-werewolf permanents. Frankly, I think that it could be a big Innistrad mechanic moving forward (though given that this is the third visit to the plane, it'll likely be a while before we return again.)