Hasn't "the Blue core" been too good since, about, 1994?
Well, blue's definitely been the strongest color this whole time! So yeah. In truth, I don't really like the term "blue core" nor any of the other various terms I've seen used to describe this, but we need to call it
something. Whatever you want to call it, the important part is to understand what "it" is, and I think that Saprolingtoken has neatly captured the heart of the issue. Explaining the actual nuances is a bit trickier...
So there's the Brainstorm + fetchland engine. The idea is to load up a deck with a full playset of Brainstorm and some combination of the most appropriate fetchlands that can grab islands from your library (Flooded Strand, Polluted Delta, Scalding Tarn, Misty Rainforest). Usually the total blue fetches add up to about 8 card slots, but it could be a bit more or less. The basic function of this engine is that you get both card selection and mana-fixing for a low mana cost. But it also comes with all sorts of little ancillary benefits that various decks can make use of. You shuffled two cards from your hand into your library, and some decks really benefit from being able to put a key card into the library rather than having it in hand. Usually the fetchlands start off by grabbing dual lands, but you can grab basics to dodge Wasteland. If an opponent tries to use a discard spell against you, then you can use Brainstorm to hide a key card on top of your library, and use your fetchland once you've drawn the card you wanted to hide. You get both an instant and a land in your graveyard, which some decks can use. Also, the reliability of this engine lets you make color splashes that would otherwise be too risky.
This engine is compact and useful enough that it's cropped up all over the format. Control decks and combo decks use it all the time. Midrange decks can use it. Pure aggro decks can't really afford to make room for it, but that's about it. As new cards have been printed in the years since 2004 (when Legacy was created), there's been a trend in which this engine works particularly well when used in decks along a spectrum from dedicated tempo to aggro-control. Delver of Secrets is probably the poster child, but the general idea was established already, with the "Tempo Threshold" archetype emerging in 2007. Perhaps that's a kind of inflection point that I could use to illustrate what we mean about this pesky "blue core." Theshold decks existed in Legacy from the beginning, essentially. But they were traditional aggro-control along the lines that I'd have expected to see in the early 00's or even in the 90's. So let's compare an early "Tempo Threshold" list to a contemporary aggro-control deck of the old style. Both of these lists are from 2007. First, here's one of the last entries I found of the old style Threshold archetype.
1 Werebear
2 Meddling Mage
2 Mystic Enforcer
4 Nimble Mongoose
4 Tarmogoyf
3 Counterspell
3 Daze
4 Brainstorm
4 Force of Will
4 Mental Note
4 Swords to Plowshares
4 Serum Visions
1 Engineered Explosives
2 Pithing Needle
1 Breeding Pool
1 Forest
1 Island
1 Plains
1 Savannah
2 Tropical Island
2 Windswept Heath
3 Flooded Strand
3 Polluted Delta
3 Tundra
Sideboard:
1 Armageddon
4 Chill
1 Hail Storm
2 Krosan Grip
1 Loaming Shaman
2 Meddling Mage
1 Misdirection
1 Seal of Primordium
1 Tormod's Crypt
1 Winter Orb
So we already have the Brainstorm + Fetchland engine backed up by Serum Visions and Mental Note. The disruption suite of Force of Will, Daze, Swords to Plowshares and Counterspell is potent and can come online quickly. You also have a bunch of cheap creatures that can pack a punch. Nimble Mongoose, Mystic Enforcer, and Werebear served as the namesake of the deck. Tarmogoyf would have been a more recent addition, but all three should give some idea of the threat that this deck posed to other decks in the format. It wouldn't do much damage in the first few turns, but it would be able to deal with threats and present some threats of its own. Brainstorm and the other one-drop blue "cantrip" spells would help the deck perform smoothly while helping fill the graveyard up. Disruption in the form of Daze, Swords to Plowshares, etc. would keep opponents from getting ahead, while also helping to fill the graveyard. The creatures would get bigger, the opponent wouldn't be able to block them all, and they'd swing in for the kill.
It's been a while and my memory isn't perfect, but I'd speculate that a list like this would have been effective against most control decks in the format at the time, and would have had the tools to outplay fast combo decks too. It would have struggled against dedicated aggro and I'd hate to have to pilot it against Goblins. But overall, it's a pretty strong list for its time. Now let's compare it to an early Tempo Threshold list, which cropped up a couple months later...
2 Mystic Enforcer
3 Meddling Mage
4 Nimble Mongoose
4 Tarmogoyf
2 Stifle
4 Brainstorm
4 Daze
4 Force of Will
4 Predict
4 Swords to Plowshares
2 Ponder
3 Counterbalance
1 Engineered Explosives
2 Sensei's Divining Top
1 Forest
2 Island
3 Tropical Island
3 Tundra
4 Flooded Strand
4 Polluted Delta
Sideboard:
3 Blue Elemental Blast
2 Engineered Explosives
3 Krosan Grip
4 Leyline of the Void
3 Threads of Disloyalty
We now how Ponder, which this this isn't quite leaning on, but it is using Predict, which synergizes with Ponder and Brainstorm. Counterspell is gone, and Force of Will is the only hard counter here, but the deck has the more efficient, and more conditional use of Daze, Stifle, and Counterbalance for disruption. This list isn't as controlling as the previous list and it has fewer creatures too, so in a way it's not as good in the aggro role while also being worse in the control role. That's why it was called "Tempo." The idea isn't to be the best aggro deck or the best control deck. It's to use stuff like Daze and Stifle to keep the opponent held back while threshold is built and the cheap creatures can come in for the kill. Instead of the hard, effective answers like Counterspell, we'd see a shift toward cheap, conditional answers that would usually work well enough for the few turns that they'd be needed. In a pinch, there was always Force of Will.
These decks would incorporate more red cards and soon evolve into "Canadian Threshold."
4 Nimble Mongoose
4 Tarmogoyf
4 Brainstorm
4 Ponder
4 Spell Snare
4 Stifle
4 Daze
4 Force of Will
4 Lightning Bolt
4 Fire // Ice
1 Rushing River
1 Wipe Away
2 Flooded Strand
2 Polluted Delta
2 Wooded Foothills
4 Wasteland
4 Tropical Island
4 Volcanic Island
Lists like this one sort of define the prototypical idea of a strong "tempo deck" in Legacy. It doesn't have a lot of creatures and it doesn't really have that many direct damage spells either, so it's not a true Burn deck. It can't pull off the crazy third-turn kills that an aggro deck in the format would aim for. And other than Force of Will, most of its disruptive cards are pretty conditional too. They won't stop every threat. They don't need to. You either stick your small threat and buy enough turns for it to kill your opponent or you get in early with enough damage that you can finish your opponent off with burn spells.
In a few more years, Delver of Secrets would be printed and this archetype would transform into the Delver archetype. Also, there was a split where we'd get a version that would swap out red for black to have better disruption and no direct damage spells, and a strictly blue/red version that would lose the benefits of green creatures but have a more stable manabase and even more direct damage. A notable feature of all these tempo-based decks, from the Canadian Threshold decks of 2008 to the U/R Delver archetype that recently got Expressive Iteration banned in 2023, is that they're pretty much never the decks with the highest ceiling of performance. There's always a chance that a hard control deck can survive into the late game and have clean, unconditional answers to anything the Delver deck can do. There's always a chance that a prison/stompy deck can lock the Delver deck out of one-drops with a first turn Chalice of the Void, or that an aggro deck can populate the board with too many threats too quickly. And a fast combo deck might just pop off and win before a Delver deck can even do anything. Legacy is a format with a card pool encompassing almost everything, and with so many great cards, the plethora of ways to win games that outclass a couple of cheap beaters is daunting. Pretty much every Legacy deck there is can mop the floor with a Delver deck, at least in theory.
The "blue core" has four things going for it that have seen some sort of Brainstorm/Daze/Force/Ponder/fetchlands tempo deck compete as one of the top decks in the format since Ponder was first printed, and seen the "Delver" subclass of this in particular rise up again and again, seemingly no matter what gets banned.
- Consistency. Sure, a dedicated aggro or combo deck that draws a superb opening hand can win in a blowout, but that deck is also going to have lots of subpar openings. With threats like Delver of Secrets and Dragon's Rage Channeler, the same spells that are reliably making your threats deadlier are also the ones letting you cheaply filter your upcoming draws for exactly what you need. With full playsets of both Brainstorm and Ponder, you're already most of the way toward being able to assemble a decent fast start almost every game you play. Opening hand's not too good? Brainstorm will fix it for you. You and your opponent killed each other's threats and now you need to be the first one to topdeck a new threat? Just cast Ponder. If it seems necessary, there's always Preordain to act as yet another one-drop hand-sculpting spell. Often, Preordain hasn't even made the cut. But really, if you always lose when your opponent has a great opening hand and always win when your opponent has a merely average opening hand, then your opponent is not able to realistically compete against you. This has allowed Delver to push some decks out of the format entirely.
- Flexibility. The core needs fetchlands to optimize Brainstorm, needs Daze to be able to make the gamebreaking tempo play of dropping a threat and then countering the opponent's own threat for free, and needs enough blue cards to make Force of Will viable. But almost everything else is interchangeable. Ponder is a best-in-slot secondary cantrip, but there are plenty of other options that are nearly as good. Everything else is just the details. The blue core has enough room to fit alongside almost any combination of colors to use whichever cards are the best in the game (so long as there's enough blue to make Force of Will a consistent panic button).
- Adaptability. The list of creature threats and utility spells that have been popular in these decks only to get dropped because something new came along or because the meta happened not to favor certain cards is a mile long. So if a ban or new printing leads some deck to have a decisive advantage against whatever top deck is using "the blue core" it's only a matter of time before players dig through the toolbox and make some card swaps to shore up that weakness. There was even a time period when a U/R/W "Patriot Delver" emerged as the best answer to the metagame, and the primary thing holding it back was seemingly the lack of Tundras in the hands of longtime Delver players, as white hadn't historically been a color they'd been splashing for a while.
- The DCI. We're talking about a style of deck that generally dedicates 20+ slots to one-drops, so it's not without weak points. It's almost always been possible to build a Chalice deck that could trounce whatever the best Delver deck happened to be at any given moment, but such a deck would be weak to the rest of the format. For quite some time now, whenever any deck comes along that can consistently beat the best Delver deck, something gets banned. Conversely, Brainstorm is off the table, and whenever Delver decks themselves are targeted for a ban, it's something like Ragavan, Nimble Pilferer, and there are plenty more cheap threats to swap in. But "the blue core" remains intact whenever that happens.
So that's sort of a condensed history of why the format is in the state it's in with regards to the predominance of this suite of blue cards. But in my mind, that's not actually the problem! I'm fine with a blue-based tempo deck being a deck that exists and is consistently one of the best decks in the format. No, the problem illustrated by the recent bans seems to be that WotC will ban a key card from any deck that steps on Delver's toes too much while always banning
around the blue core instead of targeting it directly. This leads to an ever-growing ban list. New sets come out, decks get new toys, and WotC makes aggressive bans seemingly meant to achieve overly specific goals of curating the format. They don't reevaluate those decisions, ever, and if it makes the format worse, they follow up by issuing more bans, never unbans. If that's now the pattern in the format, and it sure seems to be, things will just keep getting worse.
There are two obvious solutions. Either rip the band-aid off and ban Brainstorm or start unbanning cards. For some reason, both have become sacred cows. WotC never actually comes out and says that both solutions are off the table. But for whatever reason, they refuse to consider them. It's weird.
