Mastering Variance with Sultai Crabvine: A Modern RCQ Report

Hedron Crab MTG Art

By Dan Schriever

Last weekend I finally made it out to a Regional Championship Qualifier at Atomic Empire in Durham, North Carolina. Turnout was nice, with 69 players showing up to do battle over seven rounds of Modern.

We test lots of silly brews on the podcast, but when it’s time to play for stakes, Sultai Crabvine is my weapon of choice. The strategy has not changed much since I first learned the deck in January (and promptly came within 1 life point of re-qualifying for the PT in a heartbreaking finals loss). Following the advice of Anthony Mannino, I still preach the gospel of Rotting Rats. I also max out on Narcomoebas since other options like Bloodghast or Glimpse the Unthinkable have not earned my trust.

Anthony suggested Brazen Borrower for the sideboard, which seemed as good as anything since Assassin’s Trophy is known to suck. I also squeezed in a Spell Pierce, which has more utility than Force of Negation especially in fairer matchups. This is what I registered:

Before the Lurrus ban, I used to win at a steady 70% clip on Magic Online across leagues and bigger events. In those days, every Lurrus deck except Hammer was a great matchup for Crabvine. A revealed Lurrus meant that nothing terrible was going to happen to you: no Leyline of the Void, no Blood Moon, and probably no Rest in Peace or Chalice of the Void.

In the months since the ban, Crabvine has become significantly worse. Old enemies have resurfaced, while new foes like Omnath, Endurance, and Unlicensed Hearse are gaining meta share. Hearse in particular has transformed the Murktide matchup from highly favorable to “win some, lose some” — a devastating blow when Murktide’s popularity used to be one of the major reasons to play a graveyard deck. My current winrate is below 60%, and it’s getting harder to predict what kind of hate pieces the opponent will have access to.

A revealed Lurrus meant that nothing terrible was going to happen to you: no Leyline of the Void, no Blood Moon, and probably no Rest in Peace or Chalice of the Void.

Dan Schriever

Even so, Crabvine is a deck I understand, enjoy, and — most importantly — already own. There was no question in my mind that I would run it. It was more a question of what I would be paired against, how many blunders I would commit, and whether the top of my deck would be kind to me.

A note on variance

The “high roll” nature of Sultai Crabvine is a sticking point for some people. Generally speaking, the best lines you can take set yourself up to mill the maximum number of cards. Whether that wins the game depends entirely on how many Vengevines, Creeping Chills, and Prized Amalgams are in those top 10-20 cards. It’s possible to sequence everything correctly, make the correct reads and choices, and then mill nothing relevant and lose.

The other stumbling block is mulligan strategy. Crabvine requires an enthusiastic embrace of the London mulligan. One might even say it abuses it. Consider this: at least 20 cards in the deck are actively bad to draw or have in your hand. If we imagine our best starting hand (something like Hedron Crab, Otherworldly Gaze, and two fetchlands) we find that it only requires 4 cards total. Our last three cards in hand might be Vengevine, Narcomoeba, and Creeping Chill. Not only do these suck to cast, but they make each mill less powerful since there is less juice in the deck to hit. Wouldn’t we prefer to simply put these cards back into our library if we could? The London mulligan does exactly that, while also giving us many looks at fresh 7s to try to find juicy Hedron Crab hands.

This is what I mean when I say that your 6 card hand is usually better than your 7 card hand, and your 5 card hand is often better than your 6 card hand. To a self-mill deck, the London mulligan feels like downright cheating.

Crabvine requires an enthusiastic embrace of the London mulligan. One might even say it abuses it.

dan Schriever

So there we have the paradox of Crabvine. On the one hand, the deck is extremely consistent. We take so many mulligans that most games start off the same way, casting the exact same self-mill cards. On the other hand, what we get from those mills — and thus how powerful our hand turns out to be — is the province of Lady Luck. We do the same thing over and over, and get different results every time. It’s insanity in reverse.

Mistakes versus Bad Luck: How to Tell the Difference

All of this is to say that there is not a strong correspondence between making the correct plays and winning the game. This is true for every deck to an extent, but with Crabvine the effect can be quite pronounced. Good decisions can be erased by weak mills, and loose play can be carried by lucky hits. Tilt is an ever present danger.

But this is not to say that skill makes no difference — far from it. Crabvine lends itself to a particular style of low-resource game. We only get to make a handful of plays that will affect the outcome. We have to be disciplined with our mulligans, sequence our plays precisely, and get the most we can out of each resource (similar to Burn in this respect). We have to sideboard correctly and be smart in creature combat. That is how you win matches with chip damage from 1/1s on a mulligan to four.

Crabvine lends itself to a particular style of low-resource game. We only get to make a handful of plays that will affect the outcome.

Dan Schriever

My goal for this tournament was to keep my focus on my decision making process. Wins and losses would decide the victor of the day, but those same wins and losses threaten to muddle my assessment of how well or poorly I played.

To that end, I tried to take detailed notes after every round, to render my decisions more visible to me after the fact. These notes, I hoped, would also help me quantify whether I was “running good” or not, with more objectivity than wins and losses alone might indicate.

The Tournament

For each game, I first note the starting hands of myself and my opponent. G3 (p5*—d7) means I was on the play in game 3 and kept 5 cards, vs opponent who kept 7 cards on the draw. The winner of the game is indicated by * asterisk.

I tried to note my thought process as best I could: what cards led me to keep the hand, how much I got off each mill, and my sideboarding strategy. The grammar gets a bit loose here as I was hammering out these notes on my phone between rounds, so please forgive the abbreviated card names and laconic descriptions.

Round 1 vs Eric (Hammer)

G1 (d4* — p5): Opp mulled to 5 and kept a weak hand (Esper Sentinel but no threats). I mulled to 4 but found Gaze and Crab, which was enough. Above average mills got turn 2 Vine, Prized, Wonder etc.

In: Natural State x2, Brazen Borrower. Out: Gravecrawler, Rotting Rats, Narcomoeba

G2 (d6 — p7*): Opp has great start: Inkmoth Nexus, Ornithopter, Drum, Aid. I keep Stitcher x2, Venture, fetch, Island, and Gravecrawler. In my head I have to get Overgrown Tomb turn 1 to deploy all my Stitchers on time (because of that pesky Island). I draw Natural State on turn 1, but only briefly consider whether to use it (that is, to play fetch and pass). In my head I’ve already committed to Stitcher turn 1, which I cast. Opp plays land and promptly kills me with Hammer on Inkmoth. Should I have played around this? Should I have attempted to read body language? Or just played it safe and accepted a slower start?

No changes for game 3

G3 (p5* — d7): I keep Crab, Natural State, Gravecrawler, two fetches. T1 I land pass and they lead with Urza’s Saga which I destroy in response to the chapter 1 trigger (fetching Breeding Pool). My turn, Crab finds 2x Vengevine and suddenly this game is completely over. Opp ruefully plays Relic of Progenitus on turn 2, far too late.


Walking around the room, I see lots of Hammer (more than expected), lots of Murktide, 4c Yorion (several Risen Reefs), a few Amulet, a couple Tron. One reanimator, one Living End, one Footfalls, and fellow Faithless Brewer AllaricDeschain on 4c Creativity.

Round 2 vs Anthony (Footfalls)

G1 (p4* — d6): On the play, I keep Merfolk and Crab. Opp on 6 has Gemstone Caverns exiling Dead/Gone. I lead with Venture Deeper (find Vine + Narc + Wonder), sit tight on turn 2 (declining to play Crab into their open mana), then “go off” with the Crab on turn 3 after they tap out for Shardless Agent into Rhinos. I find 2 more Vengevines and return them all; 13 damage in the air gets the scoop.

In: Spell Pierce, Subtlety x2, Force of Negation: Out: Rats x2, Narc, Crawler

G2 (d6* — p7): I keep 6 with Pierce, Island, Merfolk, Crab, Chill, fetch. Opp suspends Footfalls, I lead on Venture (Narc, Vine). Turn 2 I draw Gaze, play fetch, pass. Opp passes their third turn. I Gaze on their 2nd main and they use Mystical Dispute. I leave fetch intact. My t3, draw another fetch, play Crab, land, mill 6 (another Narc) bring Merfolk off adventure to trigger Vengevine but leave the 2nd fetch uncracked in case of Endurance. Vine comes back, I swing for 5, they Petty Theft the Vine. Do I use Spell Pierce here? Or hold it to defend against Blood Moon or Footfalls? They had fetched basic early, but didn’t deploy a Blood Moon last turn when they could have. I decide that this guaranteed 5 damage is enough even if they have Moon (it puts them to 11) so I crack the fetch and use my Pierce. I now have 2 Watery Graves and Island in play, 2 Chills in hand, Gaze in yard. They untap, get Island, play Magus of the Moon (good thing I used that Pierce!). My upkeep, Gaze finds Chill and I attack them for 6, putting them to 1. They need Fury now to stabilize and don’t draw it.


Round 3 vs Wyt (Glimpse Elementals)

G1 (d4 — p7*): Opp reveals Yorion.  On the draw, I see three anemic hands, then keep 2 Crab 2 Gaze 0 land. This is a big risk, one I usually never take. Why keep a zero lander when a 3 card hand is perfectly capable of winning? My thinking is, if they are on traditional Yorion, I might need multiple Crabs to play through removal and fuel up for a longer game. And I think I can afford to whiff on lands once or twice; game 1 still favors me at least until they get Omnath in play. Maybe this was wrong though, or maybe I was unduly influenced by seeing no action at all in my first 3 hands, vs 4 of my best cards in the zero land hand. Opp leads on Khalni Garden and suddenly I realize how much trouble I’m in. Traditional Yorion is slow, but against Glimpse of Tomorrow I’m on a major clock and can’t afford to miss land drops after all. I indeed miss my first 2 land drops. Draw land on turn 3 but they already have 2 plants 4 clues in play at this point, so I decide not to play the land and just concede without playing anything to preserve information. Maybe I should have forced them to show me a cascade spell? Their Endurances are likely already in the main deck, so do I gain enough percentage here by conceding?

In: 3 Subtlety, 1 Spell Pierce, 1 Force

Out: 2 rats, 2 Narc, 1 crawler

G2 (p5 — d7*): On the play I keep 5 with Venture Crab Crawler. Turn 2 Crab + fetch, mill nothing. Opp interrupts the trigger, signaling Solitude, but changes their mind and does nothing. I decide to leave the fetch intact. Opp makes Clues (Wavesifter). My turn 3, I play another fetch. This time, Opp goes for Solitude in response to the first Crab trigger, a blunder on their part. This lets me crack both fetches in response. I end up milling 9 cards (16 total so far) but all I find is a Narc and a Gaze (I have milled 3 subtlety 1 force, showing the danger of sideboarding too much). I Flashback the gaze in response to Narc trigger but still find mostly nothing. At this point I’ve blown all my action and have almost nothing to show for it. The game continues for a while, they get Risen Reef and then Omnath, while I eventually draw more Merfolk but no Crabs. Omnath gaining 7 per turn keeps them out of range of my random Gravecrawlers (with Wonder) and the odd Chill. On a couple turns they did leave themselves within lethal range but I would have needed to draw something like Gaze into another Gaze into Chills + Vines. They did side in some useless stuff like Knight of Autumn, so the early concede game 1 wasn’t a total waste, but I needed to hit more action off my Crab triggers or draw more Gaze.


Round 4 vs Jesse (Hammer)

G1 (p6 — d7*): On the play I keep Gaze, Merfolk x2, Stitcher, Crawler, 1 land. This is clunky but will get there eventually. Gaze bins 2x Prized and puts land on top. Turn 2 Stitcher finds Crawler, return that to get both Prized back. This would normally be an ok start, but opp is on Hammer with T1 Aid into T2 Stoneforge (fetch Hammer) Ornithopter and t2 Saga. Once the Shadowspear hits it will be game over, so I need to move fast. I attack for 9 (throwing away Stitcher to mill 3 more cards) but opp hasn’t shock fetched at all so they stay at a comfy 9 life. Their turn, hit me to 6 with Hammer on the unblocked Stoneforge. Shadowspear is coming next turn so I need to kill them now. My turn 3 was weak (double Venture, find Vengevine but can’t return it) and on turn 4 I contemplate two lines but both leave opp alive at 1 life. Shadowspear comes t4 and kills me. Disappointed to lose this one. My hand was grindy but the matchup called for pure speed. Possibly if I save Stitcher for defense on Turn 3 I force them to equip Hammer to Ornithopter to hit me, but does that make a difference? I would have milled 3 fewer cards.

Same changes as Rd 1

G2 (p3 — d6*): I look at five opening hands but three have zero action (as in, five lands, Wonder, Rats) and one has Crab and lots of action but zero lands. I have to settle for a very sad 3 card hand (shock, fetch, Merfolk). Venture finds Gaze and nothing; Gaze flashback finds nothing, and I die without doing anything. It’s a shame because opp had almost no sideboard to bring in, just 1 Relic of Progenitus.


Over the last two rounds my deck felt barely functional. I could have chosen differently on some things (R3 G1), but I also needed better mills (R3 G2) or a better matchup (R4 G1). Will need to ponder these decisions during the post-mortem. I hope for better showing the next couple rounds.

Round 5 vs James (Hammer Quest)

G1 (p4* — d7): I keep Gaze + 3 lands, not a great start. But opp kept 0 lands(!). Gaze finds Chill Chill Gaze. Flashback Gaze turn 2, find 2x Rats. Opp whiffs on land again (discarding to hand size). It turns out they had a Quest for the Holy Relic plus 5 zero drops that would have got Argentum Armor for a likely turn 1 kill. But they don’t find land until turn 4, and by this time Gaze has found a Crab, milled some Vengevines, unearthed Rats and cast Crawler to return Vines.

In: Natural State x2, Brazen Borrower. Out: Rats, Narc, Crawler

G2 (d5* — p6): I mull to 5 and keep Crab, Gaze, Stitcher. Opp seems to have mentally given up at this point, and after playing Aid turn 1 they don’t present anything. I mill a bunch of good stuff, bring it back and opp concedes without fighting back.


Round 6 vs Matthew (Mono Black Coffers)

G1 (d6 — p7*): I keep Crab, Crab, Venture. Opp leads with Inquisition into Thoughtseize to discard both Crabs. I still have my engine going thanks to Venture (finding Gaze, finding more self-mill) but I’m slowed down. I get stuff in play and knock them down to 5 life. On opp’s t5 Profane Tutor comes off suspend and they play Damnation + Bojuka Bog (which they tutored for). Control is usually an easy win in game 1 but this particular sequence is devastating. Out of gas, I brick the next two draw steps and they take control.

G2 (p7 — d6*): I have a weird feeling this game. I’m expecting them to bring in Leyline effects, which coupled with their discard and sweepers means I might not want to mulligan too low for self-mill pieces. Keeping 7 and playing to the board for chip damage, with the occasional burst of self-mill if Leyline isn’t in play, might be a winning strategy. With this in mind, I keep Gravecrawler, Narcomoeba, Brazen Borrower, Vengevine, and 3 lands. This hand breaks all my normal rules but it adds pressure every turn while potentially providing a window to bounce Leyline and get a good self-mill turn. That was my thinking anyway. Opp indeed mulls quickly, but keeps 6 and doesn’t play Leyline. Instead they play Dauthi Voidwalker on turn 2. I follow the plan, getting in for chip damage, and use end step Petty Theft on t3 to set up a burst of self mill on t4. Opp is surprised and falls down to 5 while I get a bunch of creatures in play and still have Brazen on adventure and Vine to cast from hand next turn. Opp plays Damnation, but no Bog. I draw land and hardcast Vine, attacking them down to 1. Profane Tutor comes off suspend and opp goes deep into the tank, to the point I have to remind them to play faster to leave time for a game 3. Looking dejected, they finally choose a card (after putting back their first three choices), then draw for turn and visibly brighten and say “Well that changes things!” Opp plays Golos, fetching Bog to wipe out my graveyard and present a 3/5 blocker for the Vine. I draw nothing, and have to pass back intending to cast Brazen on end step for another shot at lethal. Opp replays the Voidwalker, and when I cast Brazen they immediately crack Expedition Map and use Fatal Push to kill the faerie. I have two more draw steps to find the last point of damage but I don’t draw anything and lose.


Round 7 vs Bryce (Murktide)

G1 (p5* — d7): I keep Gaze, Stitcher, and lands. Opp leads on Spirebluff, signaling Murktide, but then doesn’t cast anything for 3 turns. Even when I draw and cast Hedron Crab + fetch they don’t do anything. Eventually, around turn 3-4, they deploy Ledger + DRC and sling some removal spells, but it’s far too late at that point.

G2 (d7 — p7*): I didn’t write down what I kept this game, but the crucial decision was whether to fetch basics on turn 1 + 2 (Island Swamp) out of respect for Blood Moon. I opt to fetch a dual on t1 for better sequencing turn 2, but get quickly punished when opp immediately fetches Island (signaling an incoming Moon). I am able to fetch one Island but Moon hits on t3, plus their DRCs on t1 + t2 don’t give me enough time to draw out of it.

G3 (p6* — d7): Opp showed multiple Moons and a Hearse last game (off DRC triggers). I keep Stitcher + Gaze, finding Crab off the t1 Gaze. This gets some stuff into play t2 and I also have Island, insulating me from Moon. Opp eventually fights back but is down to 1 life. If I can trigger Vengevines I will win. I draw Narc, which would be a 3nd lethal attacker (combined with my Gravecrawlers) since they only have DRC that can’t block thanks to delirium. But if I play Narc, I’m empty handed and still 2 creatures away from triggering Vines (crawler is in yard, so any Zombie will also work). I take a risk and decide to play Narc. Opp successfully defends with removal + 2 Murktides. My draw step will be the last turn of the game one way or another. I draw Rats, which lets me cast Crawler and return the Vines for lethal. In retrospect, it was a needless risk deploying that Narc; I should have held it to improve my odds of triggering Vines on my turn. Bad job by me, but Lady Luck bailed me out.


The verdict

I finished in 20th place, good for a nifty Lava Spike promo. More importantly, I got some useful data to dissect my choices after the fact. So how did these particular seven rounds stack up against my expected results with Crabvine?

As promised, I took a huge amount of mulligans. I took 29 mulligans across 16 games, for an average of 1.81 per game. This equates to seeing 19.67 cards per game during the pregame phase. There wasn’t a strong correlation between hand size and result. I kept 7 cards twice and lost both times (LL). I had the strongest results at 5 cards (WWWL) and 4 cards (WWWL). I went to 3 once (L) but perhaps should have mulliganed the zero-land 4 card hand as well. My most common starting hands size was 6 cards (WWLLL).

I found myself missing this friendly face

Beyond the raw quantity of cards, I did feel that it was harder than expected to find Hedron Crab. Despite taking 1.81 mulligans per game (seeing ~19.67 cards), only 50% of my games began with Hedron Crab in opener. This was a colder streak than usual, considering that the chances of finding a Crab in any given 7 cards is already 40%.

More broadly, I felt like I was struggling in some rounds to find anything keepable or playable. There weren’t a lot of borderline hands this time around (e.g. Stitcher + Secretkeeper); it was mostly “does nothing, have to ship it” or it was an acceptable hand.

This is interesting, because I did leave the event wishing for a slightly higher percentage of keepable hands. But with hindsight, perhaps it was just an unlucky day for opening hands. It’s not like there’s an easy fix either; Glimpse the Unthinkable, Dream Twist, and Minister of Inquiries are all cards I’ve tried in the past to increase the percentage of keepable hands, but each has been a disappointment. Progress might require a new printing for the deck, and who knows when that will be?

As for the quality of the self-mills, I noted several games where I felt like I was getting too lucky: multiple Vengevines in the top 10 cards, for example, turning close games into routs. On the flip side, in a couple games I milled many cards but found almost nothing, turning winnable games into anemic losses. There isn’t a fix for this either, it’s just the nature of Crabvine. Luck and skill are both required for victory.

Wrap Up

I wasn’t the victor in this RCQ, but I enjoyed the event. Most importantly I enjoyed the exercise of keeping track of my decisions and outcomes, as best I could. It helped me shift focus away from things I can’t control (”I hope I get good matchups,” “I hope they don’t draw their hate card this turn”) toward the decisions that I actually did make.

There’s much more I could say about the deck, how to build it, heuristics for mulligans and sideboarding, and the like, but that’s a topic for another day. We’ve covered these in depth in the podcast before, so if you’re interested in Crabvine I’d direct you toward those discussions next.

Best of luck at your RCQs and happy brewing!

Ready to take the Oath of Brewers? Patreon supporters get access to our Discord channel, bonus content, and more. Join the Faithless Family and come brew with us!
Become a patron at Patreon!