How exactly does the deck shuffler work?

[Mr.Black]

Is it like truly random or is there some sorta idealized drawing system at the start of every match?

For the most part the shuffler in a normal 60 card deck is somewhat ok, but going past that to somewhere between 60 and 70 card it always tend to go haywire even when i try to keep the ratio of lands to other cards about the same.

Id have some matches where im flooded with lands or get 2 lands at the beginning of the game and wont see another land for 5 turns.

I'm more likely to draw my 1 copy of a card i added to to reach the 60 card minimum in some cases within the first few turns than any other copy. This has happened consistently in a lot of matches.

[anaris]

Randomness really operates on a scale; the random here is a mersenne twister (a pseudorandom generator) seeded by 256 cryptographically-secure random bits (which are likely to be true random or a random sample of an unpredictable process like atmospheric noise, both of which are usually described as true random).

Mersenne Twister passes various tests to show its results are indistinguishable from random in Arena's most likely use case (it probably generates a new seed often enough).

Thing is, humans judge randomness really badly. One thing we know from research on randomness is that humans think true random looks nonrandom and evenly distributed, precisely-ordered data looks random, when the opposite is true. That's most likely what you're seeing.

Oh, and don't run decks larger than the minimum size, they're always worse

[anaris]

there IS a "hand smoother", which shuffles three copies of your deck, draws a hand from each, and then randomly determines your hand with a higher weight for hands that have the same ratio of mana as your deck, but this will not always save a 250 card deck (because ratio is not the only relevant factor)

[$tump]

Larger decks require a focus on draw and discard behavior.
FE: cards that allow you to draw/mill 4 discard/return.

Play from your graveyard or benefit from it.
Control mage, necromancer, or spell thief. To name a few styles.

[zahlenmaler]

Any proof code that this "handsmoother" is not a fairytale?

[anaris]

Originally posted by zahlenmaler:

Any proof code that this "handsmoother" is not a fairytale?

well personally the third time they said publicly it was a thing was enough for me lol

[3xn7]

Nobodies going to tell you this but in those games where you get 2 lands and you don't see another land for like 5 turns, the person you're playing against is CHEATING! They have a cheat that re-arranges your cards, have you ever noticed everyone you play against never mulligans and almost always has land?! That's how bad cheating in this game is, it's like 99% of players. Nobodies doing anything about it because this isn't the real internet and this isn't the real steam, these are all dudes who kidnapped us as children and put us in machines to steal everything we make while we live in a fake simulation and they spend that money buying more kids or men and women off the black market and whoever bought you or basically kidnapped you is most likely the person cheating against you in every game. Good Luck.

[anaris]

2025 is so ♥♥♥♥♥♥ up i can't tell if that's a joke

[Curfuffle]

Yes. There is a "hand smoother" for Bo1. Dvs have admitted rhis.

And it should be obvious to anyone whe actually plays.

[zahlenmaler]

Originally posted by Curfuffle:

Yes. There is a "hand smoother" for Bo1. Dvs have admitted rhis.

And it should be obvious to anyone whe actually plays.

Do they?
How to find this information, a link to a official annoucment maybe?

[Zlehtnoba]

Originally posted by zahlenmaler:

Originally posted by Curfuffle:

Yes. There is a "hand smoother" for Bo1. Dvs have admitted rhis.

And it should be obvious to anyone whe actually plays.

Do they?
How to find this information, a link to a official annoucment maybe?

It's been around for so long links are hard to find. But some were posted recently in another thread. Anyway, it's official, and yes pretty obvious if you play best-of-one. It does not apply in best-of-three.

[Sm Izumi]

I'm a speedrunner, i have been for many years, i know what's RNG or not.

The Shuffler of this game isn't. Nor the matchmaker who pick the deck counters.

If Magic was a poker game it'd be banned from all the legit poker sites and a rain of lawsuits would pour down their company.

[anaris]

Originally posted by Sm Izumi:

I'm a speedrunner, i have been for many years, i know what's RNG or not.

congratulations on the new stupidest claim on this forum

[nul]

Originally posted by Sm Izumi:

I'm a speedrunner, i have been for many years, i know what's RNG or not.

The Shuffler of this game isn't. Nor the matchmaker who pick the deck counters.

If Magic was a poker game it'd be banned from all the legit poker sites and a rain of lawsuits would pour down their company.

I'm a programmer, I have been for many years, I know what's RNG or not.

The shuffler in this game definitely is. As well as the matchmaking algorithm.

I am able to discern that Magic is in fact not a poker game, however. So it wouldn't need to worry about being banned from poker sites.

The shuffler:

Since people are asking, and it's no great secret. To shuffle decks in MTG Arena we use Fisher-Yates, pulling numbers from a Merseene Twister (MT199937), which is seeded with 256 cryptographically secure randomized bits. We use the same approach for coin tosses, only we're looking for a 1 or a 2 rather than a whole deck of cards.

As well as... In best of 1 formats, it will shuffle two copies of your deck. Then it will check both opening hands to see which one has the best land to nonland ratio based on the ratio of your deck. Then once it has selected one of the two decks, it presents it's opening hand to you. Any further mulligans are not affected. The library itself is not modified.

The matchmaking:
In unranked, best of 1, non event:
Your deck calculates a weight based on the cards present in the deck, as well as your commander for Brawl and Standard Brawl. The weight is based on how well the cards perform, but not based on the combination of cards. (So playing a card that is broken in a combo but trying to use it fairly will still have a higher weight than you suspect)
It will also use some level of skill based matchmaking, but not as heavily as ranked.

In ranked:
Matchmaking is purely based on your rank.

Other circumstances:
Matchmaking is pretty much random. Not sure of the details. They might make it still slightly skill based, so that queues like starter deck duel is more fair for new players? Not sure. I don't think WotC has ever spoken on this.

In all cases:
The longer you wait for a match, the more loose it's matchmaking becomes. So if you wait for long enough without finding a suitable opponent, it will stretch it's criteria wider to get you into a game faster, possibly giving you a weaker or stronger opponent than anticipated. A lot of games do this. I kind of wish there were an option to turn it off. Especially brutal when you're new to a fighting game.



Edit:
I have said many times to people in these forums. If you feel it's rigged, it could be that your deck simply isn't consistent enough. I usually have better luck when I'm refining my deck after a few matches. Seeing what goes wrong and when. What cards feel unimpactful. Etc.

[anaris]

Originally posted by nul:

Then it will check both opening hands to see which one has the best land to nonland ratio based on the ratio of your deck. Then once it has selected one of the two decks, it presents it's opening hand to you.

Minor note: apparently proximity to the deck's overall ratio weights a hand more highly, but doesn't guarantee it will be selected.

Other circumstances:
Matchmaking is pretty much random. Not sure of the details. They might make it still slightly skill based, so that queues like starter deck duel is more fair for new players? Not sure. I don't think WotC has ever spoken on this.

many longtime players think that there's a general "starter deck" effect where using one of the actual starter decks gives you an easier matchmaking selection and favours other starter decks, even in regular play queue

[Zlehtnoba]

Also, the hand smoother was changed to now pick between three shuffles.

Great post, thank you for the quotes.