Stop Playing Blood Moon in cEDH
Blood Moon by Franz Vohwinkel
I'm a huge fan of all things control, stax, and prison across Magic. I'll happily play worse decks if it means I get to cast more counterspells, or effects that say "players can't...," or anything else in that arena. That being said, I'm also among the first to look at a lock piece and think "this...probably isn't good." So, with that in mind, it's time to talk about one of Magic's oldest prison pieces: Blood Moon.
What Blood Moon Wants to Do
Coming in at two generic mana and one red, Blood Moon is an enchantment with a single, powerful line of text. "Nonbasic lands are Mountains." So, what should we make of this?
At face value, Blood Moon is a card with a universal effect, but in actual play this is one of the most one-sided stax effects in the game. Unlike cards like Winter Orb or Static Orb, which require direct manipulation in order to break through their affect, Blood Moon requires no such combo piece provided that your manabase is built accordingly. In a mono-red deck, for example, Blood Moon is entirely one-sided. Your spells only require red mana, anyways, so what does it matter if something like Ancient Tomb becomes a Mountain? Meanwhile, your opponents will slowly struggle to piece together any combination of colored-mana-producing artifacts they can get their hands on, putting you up significantly in resources and easily outpacing the table.
Blood Moon's best comparison, in terms of readily breaking parity purely through deck construction, is almost certainly Deafening Silence. Deafening Silence prevents players from casting more than one noncreature spell a turn, but the decks that run it are barely effected by that restriction. Instead, they're so busy with playing creature spells turn after turn that the noncreature restriction is negligible. Why play one mana rock a turn when you can cast mana dork after mana dork instead?
Now, I know that I've largely glossed over the keyword "nonbasic" in Blood Moon's effect, but that's because this is largely negligible. Most cEDH decks nowadays have manabases with barely, if any, basic lands in them, and those that do run basics will usually grab them off of fetchlands in the later turns after the other fetchable lands have been exhausted. As such, unless your opponents are expecting a Blood Moon and expecting it early, the odds are in your favor that you'll never have to deal with a basic land hitting the board.
Why It Can't Do It
So, I've just sung the praises of Blood Moon in theory, but why not in practice? Well, it all comes down to the popularity of red overall. Red is an incredibly powerful color in cEDH, with many of the format's best cards hailing from this piece of the color pie. Jeska's Will? Red. Dockside Extortionist? Red. Underworld Breach? Red. The list goes on and on. So, what do these cards all have in common? They're all threats: cards that want to, and readily can, end the game.
Blood Moon is a card that tries to slow the game from progressing, but really what it does is slow players from interacting. Yes, Red Elemental Blast and Pyroblast both exist, but, with a Blood Moon on the field, chances are very slim that any blue spells will be cast. The result? Blood Moon operates far more akin to a Defense Grid than it does a Rule of Law, and anyone that's played cEDH long enough knows that you should never pass the turn after casting a Defense Grid.
Despite the seemingly constant release of free counterspells - Flare of Denial, Subtlety, Force of Negation - cEDH is still a format populated by interaction that costs mana. Swan Song, Flusterstorm, An Offer You Can't Refuse; all of these are important means to regulate the flow of a game, and all of them cost non-red mana. Blood Moon shuts all of this off, opening up the stack for players to win the game uninterrupted. Shutting off low-cost interaction might not be as valuable as shutting of zero-cost interaction, but it's still significant enough that passing the turn after casting a Blood Moon can very easily hand the game to another player.
This brings us back to the list of threats I mentioned earlier. The very existence of Dockside Extortionist further serves to invalidate the usefulness of Blood Moon, as it isn't just a popular threat roaming around cEDH tables, but also an escape key from the lock created by Blood Moon. Thanks to the plethora of cEDH's mana rocks, odds are that players will still have a hefty artifact count for when Dockside Extortionist comes down, meaning that resolving Dockside Extortionist against an opposing Blood Moon isn't just a ritual, but a burst of color filtered mana which is often sufficient to either deal with the Blood Moon or just win through it.
As a comparison, I want to briefly talk about the newest twist on Blood Moon, Harbinger of the Seas. Mana cost and card type differences aside, the most important difference between these two cards is that Blood Moon turns lands into Mountains and Harbinger of the Seas turns lands into Islands. At first, this may sound worse - after all, you can't cast a Rhystic Study with solely red mana - but it's actually this difference in mana production that makes Harbinger of the Seas the stronger effect. Allowing players to interact with the full countermagic suite as the game goes while simultaneously shutting off cards like Dockside Extortionist and Underworld Breach means that you have more control over the pace of the game since the one-card threats are now far more readily answerable.
Wrap Up
Blood Moon's story is one of suffering from success; the success of red, that is. If fewer players jammed red in their decks, or even if Dockside Extortionist simply didn't exist, then odds are Blood Moon would be in a much better spot. But, alas, Dockside Extortionist does exist, not all countermagic is free, and sometimes it's better to let people cast spells to help moderate the game than it is to lock them out and pass the turn.