So, lately this has become a thing across several play groups I am in, and it irks me to no end. Some guy combos off by gaining some way to shuffle his library an infinite number of times, and now, because over an unspecified number of shuffles, the probability that his deck ends up in exactly the order he wants approaches 100% and he has cards x, y, and z in his deck, he declares victory.

In tournament Magic, loops like this this can't be shortcut, and after failing to do anything relevant in the first few go-arounds, the judge is supposed to tell them to do something else or issue penalties for slow play (MTR 4.4). But these guys always claim that since Commander is not sanctioned, and that there are no rules about slow play in the CR or any penalties for that matter, there is no way to enforce the MTR and they should be able to skip to the end despite the loop being non-deterministic. This always ends with someone getting upset, either when the playgroup agrees that they won't let them shortcut or when nobody can agree on what to do.

Is this a bug in the format or a feature? Can we get a rule to put a stop to this kind of thing, or is this the kind of play that is encouraged?

If this isn't a sanctioned tournament, then you need to enact the social rules of the game.

1. Don't like someone? Don't play with them.
2. Don't like someone's deck? Don't play against it. Ask them to use a different deck. If they refuse, see #1.
3. Agree to house rules before the game starts.

Or you can let him continue to combo off, and while he's shuffling his deck to get it perfect, you all can start a new game without him.

Once the guy sits out enough games he'll get the idea.

What his is doing is not legal.

You cannot shortcut game actions unless a rule specifies a way for you to do this (whether it is in the Comp Rules or the MTR). There is no such rule for non-deterministic sequences of actions.

Even assuming he could shortcut this sequence, there is no way for him to stop when the top three cards of his library are specific cards in a specific order unless those cards would be revealed to him each time he does the sequence (and in time for him to act on that information).

The comprehensive rules are written such that you CAN'T do anything that isn't allowed, not such that you CAN do anything that isn't forbidden.

He can try to resolve the combo without shortcutting it, and sure, there is no judge that can call him on slow play, but I would never allow someone to call this a win, because it isn't.

I don't actually care about the comboing off part. I care about the the theoretical probabilities part. Like, if you can't demonstrate even one iteration of your loop, why should I let you skip to the end? Just saying you win because your math equation says you'll get there at some point before the heat death of the universe isn't even playing magic. By that same token I can hold priority during your turn and never give it back because you are statistically likely to die over a long enough period of time, and hey the CR doesn't specifically say I can't, so I win.

There is a big hole in between the CR and the MTR, and Commander lives there. I just think it might be worth plugging that hole a little.

Isn't the correct answer "congratulations, you're infinite, have a cookie, now bugger off and let us finish the game"? YMMV.

I'm interested in this combo. Eventually you'd end up with the perfect combination on top of your library. That might happen. It is a lot less likely than the all-land starting hand, but I have experienced that. But then, how would you know the perfect combination is on top? Does he also have a way to draw the cards? If not, there'd be no way to see if the card combination is perfect.

One loop was Gitrog Monster in play, go to cleanup with 8 cards in hand, discarding and dredging forever with a Kozilek in the library, and the "combo" was that, statistically, with enough loops through the deck, he will eventually draw and cast Dark Ritual enough times to create infinite mana, and then draw and cast Necromancy enough times to reanimate Zulaport Cutthroat enough times to kill everyone. Note that there was no additional discard outlet or way to keep more than 7 cards in hand through each additional cleanup step.

The other one was Future Sight in play and the Cephalid Breakfast Combo, Gaea's Blessing doing the shuffling, eventually letting him stack his deck in any way so he could storm off.

There's a difference between using probability to claim you win and the ability to actually demonstrate a win. As people have already stated, shortcuts work when you can demonstrate that you can yield a neutral or positive result when it comes to the generation of mana/tokens/damage, etc. Stacking the deck is not one of those things - statistics are only going so far. I will attempt to show some examples.

Ex 1. Mill decks can't mill out a deck with an original Eldrazi titan ( & ) in it, unless they can manage to do one of the following:
1) Cause the player being milled to draw more cards than they have in their deck, in response to one of the titan's reshuffle trigger.
2) By exiling the titan in response to it hitting the graveyard and the trigger being placed on the stack. (or all the cards with something like )
3) Somehow stealing the Titan(s) from their deck to prevent the anti-mill.
4) The player being milled draws the card(s) in question or you force them to draw into it before continuing the mill.

This is due to the interaction of how the Eldrazi Titans prevent mill strategies. They're not unbeatable, but without a silver bullet answer like the ones mentioned above. Infinite mill potential on a player's turn doesn't really do anything. You could say that "statistically" there could be a scenario where the eldrazi titan(s) are among the last few cards in an opponent's deck, but that doesn't allow you, as the one forcing the mill, to shortcut to that potential outcome.


Ex. 2 (competitive decklist) On my turn, I have , , enough mana rocks to generate 3-5 mana and plus a card in hand to cast. I use Sisay to tutor for and cast and resolve it since no one can counter anything I do, short of something like or . My turn is my own and no one can interact with me or what I do. I can and likely will then pull out every legendary non-land permanent and play them. The cheap ones net me mana in this example and allow for the ones over the 3-5 mana cost that the rocks/dorks are producing between each spell tutored/cast (nevermind any open lands). Something in the list is bound to give everything haste, such as . and and any of the other pieces I'll draw into will enable infinite mana, infinite pump.

In this example, there is a repeatable set of actions that I can follow, that will net me mana or remain mana neutral, flood the board with legendary creatures/non-lands, where no opponent can react, and that will result in lethal damage regardless of how many creatures are on the board. I've done it in my play group enough during competitive games that if those pieces are there, I tell them what I'm going to do, and they acknowledge the win and we swap decks and shuffle up.

Statistics do not justify shortcutting outcomes because of the potential that exists for it to occur. It's the reason why the new + doesn't allow you to shortcut to 50-75% of your opponent's creatures being destroyed. An increased chance to get the outcome you want doesn't justify anything.

I think there's a misunderstanding brewing here, and it might need some clean up... if I understand majikal right (chime in if I've misspoken), the question is essentially, "Are the 4 Horsemen combo and other similar endgames legal in Commander? If so, is that a problem? If it is a problem, what can we do about it?"

First off, Four Horsemen is not the most straightforward combo to grok, so instead of trying to explain it, this is the SCG deck tech that explains one of the original versions of the combo, and why it is impractical for tournaments (unless your goal was getting a DQ for stalling). 4 Horseman and similar loops used to be rare in Commander, but as magikal points out, with The Gitrog Monster, its relatively easy to set up (you need Gitrog in play, and 8 cards in hard when you end your turn, and one of those cards is Dakmor Salvage).

spacemonaut is technically correct that the rules governing shortcuts are in the Magic Comprehensive rules (CR); unfortunately, those rules also refer you back to the Magic tournament rules (MTR) and infraction procedure guide (IPG) for appropriate remedy. So, the Four Horsemen combo cannot be legally shortcut as described in the CR... but the CR provides no insight on what to do when the combo is assembled.

So 4 Horsemen leaves Commander in a weird spot. Shortcutting the combo is illegal, but manually playing a combo that likely lasts until the end of time is legal (so the combo is... legal? I guess?).

Personally, I've got a friend in my group who runs the combo in his Gitrog deck, and I don't have a problem with it. (I mean, it's aggravating when he gets the combo win with Gitrog before I get it with Melek or whoever, but that's life in c/edh.) When we're playing with cutthroat decks, we usually allow deck-stacking as an acceptable shortcut, so if he assembles it, he gets the combo win golf clap and we go to the next game. It's an extraordinarily frustrating deck to play against someone who's not playing our same style though.

I also feel like this is one of the donut holes that the Commander rules don't do a good job covering, but I don't have a good suggestion for a remedy.

Tl;dr

Is magikals problem combo legal in Commander? Yes
Is the combo a problem for the format? Probably - reddit and other mtg communities have been fascinated with it for the last year or so. It seem likely players are using it to aggravate each other
What can we do about it? shrug; probably needs RC attention

Kemev hit the nail on the head. Kudos for that explanation.

I remember this same discussion back in 2010. viewtopic.php?f=2&t=4283&hilit=Shuffle

At the time I felt in the minority that it wasn’t a legit shortcut, but it seems that time has swung things to my side. The end of that 9 page discussion was just that for some it feels right and for some it feels wrong. It probably should be decided before a game starts if possible.

This seems like the time to pull out a house rule (assuming you're playing at your place and can enforce the rules - or then at least suggest it ahead of time) that I heard some people have in the past: Any Infinite Combo, your max # of iterations is X.

So you put a cap on how many times you can do something if you can prove it's actually infinite. I've heard X ranging from 5-6 up to 100 or so.

I can see it keeping weird/fringe combos like this away from the table as it neuters them, but anything like "Infinite Memnarch Activations" can still be done enough to be worthwhile (all depends on what you set X to of course.)

In an old group of mine, the host had the rule of: "Activating Mindslaver once is fine. If you recur it, I exile it instead." Simply because recurring Mindslaver was cool the first time... then it lost it's charm quickly (and one player seemed to want to keep doing it.)

Back to the original topic - I think with this combo the 'solution' is: No, you can't shortcut it (see other posts above for why you can't); and if you insist on trying to play it out and make us just sit around, then we can opt to just concede and start another game without you. So make a choice: Try to get the combo to go off how you want it, or let's just play. So in other words, using social pressure.

The other thing I suppose you could do (and may or may not work well) is to make them play it out, and don't let them take back any moves that are wrong, so the combo may disrupt itself by sloppy play of the player.