Magic: The Gathering is Turing Complete · HackerPapers discussions

Magic: The Gathering is Turing Complete — mentioned by akoboldfrying

Fri, 12 Jun 2026 03:00:59 GMT

I was wondering how complicated it could really be, and it turns out that some people showed in 2019 that it's Turing-complete -- meaning that any conceivable computation can be simulated by a MTG game, indeed a game in which every move by every player is forced: https://arxiv.org/abs/1904.09828 IOW, it's as complicated as possible.

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Magic: The Gathering is Turing Complete — HN submission

Fri, 03 Apr 2026 13:11:51 GMT

Magic: The Gathering Is Turing Complete

1 point; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — mentioned by FartyMcFarter

Tue, 24 Feb 2026 12:50:44 GMT

I don't know much about CSS, but Turing completeness is notorious for showing up in systems unintentionally. It doesn't take much to be Turing-complete - if a system provides unbounded read/write memory plus branching or conditional recursion you're usually there. As an example, Magic The Gathering (the card game) is Turing-complete: https://arxiv.org/abs/1904.09828 . You can use creature tokens as memory and various game mechanics to do flow control. Was this intentional by the designers? Most likely not...

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Magic: The Gathering is Turing Complete — mentioned by orf

Fri, 24 Jan 2025 16:15:36 GMT

> There's several use cases to virtualization Containers are not virtualisation. > So whatever you do with docker can also be done with type 1, 2 virtualization This statement is redundant. Whatever you do with docker can also be done with a Turing machine built using magic the gathering[1]. > There's plenty of junior programmers… And there are plenty of junior programmers who think containers = virtualisation :) 1. https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by jfengel

Thu, 12 Sep 2024 18:40:21 GMT

It's not advantageous. It's merely amusing. MtG is a deck-building game, rather than a board game. They keep issuing new kinds of cards, with new capabilities. You can make your deck out of any cards you like (depending on who is running the game). The number of possible interactions is vast, and people delight in discovering clever combinations. Sometimes those combinations can even break the game (like, winning before your opponent even begins). They're so powerful that they're made illegal. A key element of the game is that you will draw your cards in random order, so even if you have a…

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Magic: The Gathering is Turing Complete — mentioned by anitil

Wed, 04 Sep 2024 06:49:47 GMT

I love the whimsy of this. I'm not familiar with Magic, but now I wonder - is Magic Turing complete? And of course the answer appears to be yes! [0] [0] https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by QuadmasterXLII

Wed, 15 May 2024 02:28:23 GMT

[Turing complete you say?](https://arxiv.org/abs/1904.09828)

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Magic: The Gathering is Turing Complete — mentioned by eesmith

Wed, 27 Dec 2023 09:07:26 GMT

> is the game? Sure. One of the "Surprisingly Turing-Complete" examples is that "Magic: the Gathering: not just TC, but above arithmetic in the hierarchy ". See https://arxiv.org/abs/1904.09828 for the preprint "Magic: The Gathering is Turing Complete", https://arstechnica.com/science/2019/06/its-possible-to-buil... for an Ars Technica article, and https://hn.algolia.com/?q=magic+turing for the many HN submissions on that result.

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Magic: The Gathering is Turing Complete — HN submission

Thu, 14 Dec 2023 20:35:54 GMT

Magic: The Gathering Is Turing Complete (2019)

135 points; 70 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — mentioned by ljlolel

Tue, 05 Dec 2023 10:27:36 GMT

This is buried but fascinating: magic the gathering is turing complete, probably even more complicated than simply uncomputable , and possibly the most complicated major real world game https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by ben_w

Tue, 05 Dec 2023 10:20:14 GMT

2ⁿ > n ∀n ∈ ℕ (n>1), therefore while the test is trivial to define for any finite system, in practice you can't do that many steps even for very small n — n=256 states is 2^256 tests is just shy of 2e26 years if each test takes one Planck time. For a purely theoretical system (which includes the abstracted rather than physically implemented rules of MtG as used by Churchill, Biderman, & Herrick in their paper), n is effectively ℵ₀. https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by fauria

Tue, 05 Dec 2023 07:09:22 GMT

It is actually Turing Complete: https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by sciolist

Tue, 05 Dec 2023 05:10:12 GMT

Here's a paper on creating a Turing machine in Magic: https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by jachee

Tue, 25 Jul 2023 22:57:34 GMT

So, Magic: the Gathering (being Turing complete[0]) is a programming language? [0]: https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by nyrikki

Wed, 14 Jun 2023 22:33:44 GMT

Note that Magic: The Gathering is Turing Complete https://arxiv.org/abs/1904.09828 Something being Turing Complete just that means in principle it could be used to solve any computation problem. But this may require infinite memory or infinite time. printf() is Turing complete as an other example. https://www.ioccc.org/2020/carlini/index.html The paper showed that Transformer with positional encodings and rational activation functions is Turing complete. Rational activation functions with arbitrary precision make sure that you are in the smaller countable infinities, where floats run into…

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Magic: The Gathering is Turing Complete — mentioned by trynewideas

Mon, 26 Dec 2022 18:18:16 GMT

Computationally complex; "Churchill and co’s key result is that determining the outcome of a game of Magic is non-computable," making the claim that Magic is the first "undecidable real game" to exist. From the study: https://arxiv.org/abs/1904.09828 > This paper completes the project started by Churchill [4] and continued by Churchill et al. [5] of embedding a universal Turing machine in Magic: The Gathering such that determining the outcome of the game is equivalent to determining the halting of the Turing machine. This is the first result showing that there exists a real-world game for…

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Magic: The Gathering is Turing Complete — mentioned by mdaniel

Mon, 26 Dec 2022 18:15:56 GMT

I think they're referring to it being Turing complete, which is unlikely for Campaign for North Africa (although this is the first I've heard of that game, so), and they actually do qualify their assertion with "computationally complex": > His team has measured the computational complexity of the game for the first time by encoding it in a way that can be played by a computer or Turing machine. “This construction establishes that Magic: The Gathering is the most computationally complex real-world game known in the literature,” they say. Anyway, I'm certainly glad that Technology Review has…

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Magic: The Gathering is Turing Complete — mentioned by jdmoreira

Sat, 17 Dec 2022 23:58:22 GMT

Magic the Gathering is turing complete. https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by dfdz

Mon, 05 Dec 2022 23:02:09 GMT

Turning Machines Are Magic: The Gathering [1] [1]https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — HN submission

Sun, 17 Jul 2022 00:50:27 GMT

Magic: The Gathering Is Turing Complete

3 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Thu, 09 Jun 2022 14:15:11 GMT

Magic: The Gathering Is Turing Complete

2 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — mentioned by YeGoblynQueenne

Tue, 07 Jun 2022 00:20:54 GMT

>> For one - a neural network is a universal function approximator. And Magic: the Gathering is Turing-Complete [1], but we are not communicating over an implementation of the http protocol in Magic: the Gathering. Because that would be awfully inconvenient. ______________ [1] https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — HN submission

Sun, 15 May 2022 14:10:31 GMT

Ask HN: Turing Standard Deck Card Game

It’s been known since https://arxiv.org/abs/1904.09828 that you could build a turning machine from Magic The Gathering (and it’s sort of obvious anyhow), but I was wondering if you could create an actual playable 52-card-deck game that played like the essentials of a TM. I started doing this - deal each player 5 cards then deal 10 for the “tape”, and had some starting rules for how you write a program from your five cards (incl moves and put/take). The cool part is of course that you can use the “read” (captured) cards in your program! (Sort a 1/2 UTM), but didn’t get very far. I thought this…

2 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Mon, 28 Feb 2022 18:05:37 GMT

Magic: The Gathering is Turing Complete (2019)

11 points; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — mentioned by monocasa

Sun, 07 Nov 2021 06:38:13 GMT

> I think the game design really lends itself to being enjoyed by programmers Interestingly, Magic is turing complete. https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — HN submission

Thu, 04 Nov 2021 09:39:28 GMT

Magic: The Gathering Is Turing Complete

2 points; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — mentioned by saghm

Tue, 09 Jun 2020 16:32:52 GMT

> Regarding the oblivion ring loop, there's an example of it being used on MTGO, which doesn't end well (basically seems to crash the server and/or client): https://www.youtube.com/watch?v=AGXG5rNe_tI Oh wow, I should have realized that somebody would try it out online just to see what happens! I'm not surprised it ends up with some sort of clash; given that it's Turing complete, the game engine obviously can't detect whether a current state will end up halting or not... > And here's the paper on the latest turing machine construction in mtg: https://arxiv.org/abs/1904.09828 Awesome, thanks!…

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Magic: The Gathering is Turing Complete — mentioned by rcxdude

Tue, 09 Jun 2020 15:55:24 GMT

That rule is exactly where the the construction used becomes interesting: it's built in such a way so that if the turing machine halts, the player who set it up wins the game. If it doesn't, by the rule above, it's a draw. So it's fundamentally impossible to tell the result of an arbitrary setup (and in practice you could set it up such that it halts iff some unknown conjecture is true). Regarding the oblivion ring loop, there's an example of it being used on MTGO, which doesn't end well (basically seems to crash the server and/or client): https://www.youtube.com/watch?v=AGXG5rNe_tI And…

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Magic: The Gathering is Turing Complete — mentioned by dodobirdlord

Wed, 03 Jun 2020 01:43:15 GMT

Most of the complexity is to handle a small number of cards that are essentially never used except to prompt rule puzzles. The rules have to be very complex to accommodate when these complex cards redouble their complexity by interacting with each other. Sadly, this doesn't work, because the game rules are complex enough to simulate a Turing machine, and as a result some board states are undecidable! https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by cyberfart

Fri, 08 Nov 2019 18:04:26 GMT

Related to your comment, here's the paper [0] and Because Science recently made a video about how such a game would look like [1]. [0] https://arxiv.org/abs/1904.09828 [1] https://www.youtube.com/watch?v=pdmODVYPDLA

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Magic: The Gathering is Turing Complete — mentioned by dodobirdlord

Sat, 24 Aug 2019 17:01:43 GMT

> I don't think there's a single person today that knows all the rules. Knowing the rules won't even save you, the game has undecidable interactions. https://arxiv.org/abs/1904.09828

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Magic: The Gathering is Turing Complete — mentioned by Zanni

Tue, 07 May 2019 16:49:12 GMT

There's a download link to the right of the abstract. Here's the PDF, in case it's not showing up on mobile, or whatever: https://arxiv.org/pdf/1904.09828.pdf

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Magic: The Gathering is Turing Complete — mentioned by hu3

Tue, 07 May 2019 10:26:57 GMT

Direct link to the study "Magic: The Gathering is Turing Complete": https://arxiv.org/pdf/1904.09828.pdf

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Magic: The Gathering is Turing Complete — HN submission

Tue, 07 May 2019 09:59:36 GMT

Magic: The Gathering is Turing Complete

192 points; 192 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Thu, 02 May 2019 05:04:44 GMT

Magic: The Gathering Is Turing Complete

2 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Thu, 25 Apr 2019 01:10:21 GMT

Magic: The Gathering Is Turing Complete

3 points; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Tue, 23 Apr 2019 14:47:41 GMT

Magic: The Gathering Is Turing Complete

3 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Magic: The Gathering is Turing Complete — HN submission

Tue, 23 Apr 2019 06:37:05 GMT

Magic: The Gathering Is Turing Complete

4 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.