Why doesn't Merfolk run 4 Cavern of Souls?
Modern forum
Posted on Oct. 7, 2015, 1:44 p.m. by MADMatt7777
I am fairly confused as to why Merfolk doesn't run 4x Cavern of Souls.
Here is my reasoning:
1) There isn't enough land hate in modern to threaten the it.
2) It is protection from Choke.
3) The deck only runs 1-3 counter spells in the main board.
4) You can still play AEther Vial off of it.
5) Even with all of the other non basic lands, you still have 10 Islands in the deck.
Maybe I'm missing something or overthinking it. Could someone hell me out here?
notamardybum - I believe he means why they don't run the full playset. Here is Paul Rietzl's list from GP Oklahoma City that ran only 3 Cavern of Souls instead of 4.
October 7, 2015 2:23 p.m.
I do. :)
As for why other don't, it has to do with the number of non-Merfolk spells they run that have 
in them. I only run 8 in my mainboard (2 Spell Pierce, 4 Spreading Seas, and 2 Vapor Snag) and 6 in my sideboard (4 Hurkyl's Recall and 2 Kira, Great Glass-Spinner), so I'm fine. However, if you're running Kira in the mainboard, more counterspells (Remand, Unified Will, etc.), or Monastery Siege, you may want a couple more pure sources.
October 7, 2015 2:31 p.m.
One point is as rothgar13 says, it's about having for non-merfolk sources. It's also because Mutavault provides colorless mana. Having 8 lands that can't produce when your opponent plays a Blood Moon hits pretty hard.
October 7, 2015 3:30 p.m.
mathimus55 says... #6
Blood Moon is way more prevalent than Choke in most people's areas, mainly because blue isn't really the strongest color in the format. For Blood Moon insurance I play the Minamo, School at Water's Edge/Oboro, Palace in the Clouds package to go with my Mutavault and caverns. Some decks I've seen run theTectonic Edge or Ghost Quarter route instead of maxing out on cavern. You don't have to worry about too many counter spells when you're merfolk because lots of times you'd rather AEther Vial your team in at instant speed and still be uncounterable.
It all really depends on your build. If you're maxed out with 28+ creatures and fewer non-creature spells then cavern is more doable but if you play some of the tempo/controllier lists then you usually only want 2.
October 7, 2015 3:42 p.m.
Because you don't want to flood into them because they tap for 1 and not U You need U to cast your spells.
October 7, 2015 3:44 p.m.
Mandalorian says... #8
Kind of going off what DrFunk27 is saying. You only need one on the board to cast your uncounterable creatures. having multiples on the board doesn't help you once you already have one.
October 7, 2015 4:07 p.m.
Not entirely true. Sometimes you want to cast multiple creatures in a turn, and if AEther Vial or Merrow Reejerey aren't in play, having more than 1 Cavern of Souls matters. It really all boils down to how many non-Merfolk spells that require you run.
October 7, 2015 4:14 p.m.
MADMatt7777 says... #10
mathimus55 how does Minamo, School at Water's Edge and Oboro, Palace in the Clouds serve as Blood Moon insurance?
October 7, 2015 4:54 p.m.
They're Boil and Choke insurance, not Blood Moon insurance. I think he misspoke.
October 7, 2015 4:55 p.m. Edited.
JexInfinite says... #13
If your opponent is sideboarding in Blood Moon, they're probably an idiot. 4 Caverns is Choke protection, and good against blue decks. I'd likely run 4.
October 8, 2015 2:24 a.m.
mathimus55 says... #14
Two, at modern last night I was playing against RUG twin and my first 4 lands were 2 Mutavault and 2 Cavern of Souls. That poor Vapor Snag and Annul just sat in my hand...
notamardybum says... #2
you're missing something....because they do use cavern of souls...
October 7, 2015 2:08 p.m.