Tuesday, May 14, 2013

The MTGO Shuffler

One of the most common complaints about Magic: The Gathering Online is that the automated shuffler appears to yield different results than a player hand shuffling their paper deck. There are numerous reasons why there may be a stark difference between your own shuffling and the shuffling performed by a computer. Allow me to explain in some degree of depth why this is.

What is the official definition of shuffling in Magic: The Gathering?

701.16a - To shuffle a library or a face-down pile of cards, randomize the cards within it so that no player knows their order. (From the comprehensive rules) found here.

How close is MTGO to a random shuffle?

While it is true that a computer can obtain ‘true’ random at great lengths, the MTGO shuffler is not true random. However to shuffle one does not need to obtain ‘true’ random. As has been defined a shuffle merely needs to randomize the cards within the deck so that no player may know their order.

If you enter a game on MTGO you, nor your opponent, will have any way of knowing what your opening hand will yield. You may have an average hand, flooded with lands, lacking a single land, or even open with a ‘god hand’(The most optimal hand a deck could start with). This is known as being “sufficiently” random. A player may never know what his opening hand is going to be because any pattern is not within the ability of human perception to observe.

How close am I to a random shuffle?

The simple answer is that you likely aren’t. Outside of the realm of possibility that you are intentionally or unintentionally mana weaving (stacking the deck so that after an inadequate shuffle you will draw a land every third card) most forms of human shuffling are considered weak at best. This is why casinos implement automated shuffling procedures. Humans just can’t be depended on to sufficiently randomize a deck of cards.

If you’re interested in testing how well you shuffle you may learn to do so in this article by author Michael A. Rutter. 

Why do so many people think the shuffler is broken?

-They don’t know how to mulligan effectively, blaming bad decisions on the shuffler

-They didn’t design their deck to sufficiently fill their mana needs or didn’t plan for the inevitable lack or flood of mana

-Their online shuffler experience doesn’t match up to their paper shuffling, more often than naught this is because they fail to shuffle sufficiently themselves.

-People remember disruption more vividly than they do success. (An opening hand of 7 lands will be more memorable than an average hand of 2 or 3 lands)

-They see other people complaining about the shuffler frequently so it must be broken right? People complain when something goes wrong, for every person complaining about an opening hand there are many more that played a game successfully and had no reason to complain about the shuffler.

What is the verdict?

Many people believe that a random distribution means an even distribution of cards. A randomly shuffled deck will have natural clustering of cards which will not live up to the ideal of an evenly distributed deck. The online shuffler is sufficient in that it complies with all the rules required of a shuffle. MTGO is very much a game of ‘luck of the draw’ but improved deck design and mulligan judgments can minimize the extremely unfortunate opening hands that are an inevitable part of the game.

Perhaps in the future R&D will invest time and thought into cards that will serve to help players improve their opening hands, but for now we must remember that even a great deck will lose to luck of the draw!


  1. most humans shuffle illegally when playing casually (some cheat while playing pro, you can see that in for example the puerto rico guy in worlds 2012, putting the same card on the top shuffling and keeping it on top).
    Things like mana weaving (placing a land every 2 cards ) etc, are all illegal, a true real randomization will cause to sometimes have loads of lands, sometimes none.

    Also to note that in MTGO you can play 10 games in 15 minutes, and all it takes for you to feel like the shuffler is agaisnt you is to have 1 or 2 games with bad starting hands, or the fact that you lost half of the games.

    I've also encountered lots of players that blame the shuffler on losing games when I can see that they could won it if played properly ( not forgetting flashbacks, having 3 creatures 5/5 with exalted and not attack with only 1 of them etc)

  2. Problem isnt shuffler itself,problem is who can control it.Sometimes i feel like shuffler shutting me down to 50% winrate intent.

  3. i win 95+% of every casual match i play.
    shuffler works as intended.

    how could wizards configure a shuffler to "force a 50% win ratio"? how would match your ratio with your opponents ratio?

  4. Everytime i win 7-8 match in row,after i loss 3-4 match to unbelieve mana problems maybe its bad luck maybe not,problem is u never know.