Arena to Paper: The Differences Between Best-of-One and Best-of-Three

In this ongoing article series, I’ll be striving to highlight the subtle difference between playing Magic on MTG Arena and playing Magic with real, paper cards. There are a couple of places, however, where these differences are not quite so subtle. There are a couple of places where the actual game rules are different between Arena and paper. We’ll begin with this big-picture stuff before moving on to the finer details, with this article highlighting the differences between Best-of-One and Best-of-Three Magic. You check out at my previous article on the basics of tabletop events for some additional context as well.

There are two primary ways to play on Arena. You can play “normally,” (one game at a time) or you can play “traditional,” which is played as best two-out-of-three matches. As the name suggests, the “traditional” mode of play mirrors the way people have played with paper Magic cards for decades, and the way tournaments are still held today. Playing single-game matches is something that’s specific to MTG Arena, and is not something you’re likely to find in any kind of paper organized play.

While these different formats can be identified on Arena by the presence or absence of the word “traditional,” people typically discuss the formats by calling them Best-of-Three (BO3) or Best-of-One (BO1). (Note that I had never encountered these abbreviations before the release of MTG Arena).


The Sideboard: Strategy

The most important difference between BO1 and BO3 is not the number of games played, but the presence of the sideboard. A sideboard is a supplementary set of up to 15 cards that players can use to adjust their decks between the individual games in a match. Players who primarily compete in BO1 don’t need to give the sideboard a second thought. However, the sideboard is tremendously important for BO3 play in everything from in-game decisions, to overall choice of strategy, all the way to how you construct your main deck.

Strategically, the purpose of a sideboard is to optimize your deck against a particular opponent. You can use your sideboard cards to shore up the weaknesses of your main deck, utilize cards with niche effects, or to hammer a particular strategy that you expect to face a lot. Let’s look at a few examples.



Tangletrap would be too specific to play with in your main deck. After all, lots of opponents simply won’t have flying creatures or artifacts at all. However, if your deck is weak to artifacts or your opponent has a notable flyer,  you could correct this weakness by sideboarding in Tangletrap.


Return to Nature

Return to Nature and other cards like it are traditional examples of sideboard cards. Some opponents won’t have many artifacts or enchantments at all, but when you face one who does have them, it’s helpful to have access to a card like Return to Nature.


Enter the God-Eternals

Let’s imagine that red burn strategies have been popular lately. You’re entering a tournament where you expect that some of your opponents will show up with these burn strategies. Having access to a life gain card like Enter the God-Eternals might be a great use of sideboard space. You might make this decision because your deck has a weakness to burn, but that doesn’t necessarily have to be the case. If a particular strategy is popular and you have access to a great card against that strategy, it never hurts to have the extra help!


The Sideboard: Rules

The rules for deck construction are that your main deck must have at least 60 cards, and your sideboard must have at most 15 cards (it’s best to use exactly 60 and 15, although it’s not required by the rules).

In Booster Draft and Sealed Deck, your main deck must have at least 40 cards, and all of the other cards that you drafted or opened make up your sideboard.

You will always play the first game of a match with your main deck. So if you’ve entered a tournament, there’s no changing things up between rounds. After the first game, you can sideboard anyway you choose, so long as you adhere to the previously-mentioned deckbuilding rules (at least 60 in your deck and at most 15 in your sideboard). After the second game, if the match is going to a deciding Game 3, you may sideboard again. You might change things up based on which player is going first, or you might have gathered some information in Game 2 that changes your decisions. Or you might decide not to change your sideboarding at all. Either way, after the match is finished, be sure to de-sideboard, putting your deck back in its normal configuration so it’s ready for the next opponent.


The Sideboard: How it Changes Things

As a general rule, the more extreme or focused a strategy is, the more powerful the sideboard cards will be against it. Remember the example of the red burn deck? Well, decks like that often do exceptionally well in Game 1, but then have a harder time once their opponents sideboard in cheap removal spells and life gain.

On the other hand, “midrange” decks tend to benefit more from sideboarding. Picture a medium-speed Golgari deck that has creatures, planeswalkers and removal spells. Such a deck can use the sideboard to perfect its threats and answers against a particular opponent. Against a creature deck, more removal spells come in; against a control deck, the main deck removal spells come out in favor of more resilient threats. Equally important, it’s not always obvious what an opponent might want to sideboard in against your Golgari deck.

The consequences are that extreme strategies have a relative advantage in BO1 play, while midrange strategies have a relative advantage in the BO3 format with sideboards. The biggest BO1 tournament ever held was won by Andrea Mengucci, who brought two decks to play: a super-aggressive mono-white deck or a highly-controlling creatureless Esper deck. If you wanted to beat his white deck, you would need a ton of creature removal spells, but that would make you far too weak to compete against his Esper Control deck.

The sideboard gives you the tools to fight these extreme strategies. But without it, it’s hard to be prepared for everything all at once.


The BO1 Shuffler

There’s one more way in which the rules are different between BO1 and BO3, and it concerns non-random shuffling on MTG Arena.

Naturally, any time you play Magic with paper cards, both players are required to sufficiently shuffle their decks to ensure randomness (in a practical sense, this means that there should be no predictable patterns, and neither player should know the positions of any of the cards).

This is almost exactly the same as on MTG Arena, with one exception – your opening hand in a BO1 game is not generated completely at random. Instead, the program generates two opening hands, and is more likely to give you the one with the statistically healthier mix of lands and spells. The goal of this is to slightly reduce the number of mulligans that need to be taken in BO1 play.

Note that the makers of MTG Arena are transparent about if and when they employ non-random shuffling. So in all other formats and circumstances, you should behave the same way when playing Arena as you would with a shuffled deck of paper cards. This only applies to drawing your opening hand, and only when playing BO1.

What are the consequences of this? There’s much debate over how it ought to change your deck construction and your land count. However, those effects are small and are outside the scope of this article. To make a long story short, you should simply expect both players hands to be a little bit better!

Slightly fewer mulligans, a slightly better mix of lands and spells and players coming out slightly more smoothly in the early turns of a game, on average are a few things you can expect. Remember Andrea Mengucci’s aggressive white deck? Decks like it tend to perform exceptionally well if they draw three or four lands, but are dramatically weakened in the games where they draw too few lands or too many lands. A perfect choice when you factor in the BO1 shuffler!

If you’re struggling to beat an opponent who plays out three or four creatures in the first three turns, then you might want to consider a new strategy. You’re going to see that a lot when you play BO1.

On the other hand, if you’re used to playing BO1 on Arena and you decide to take the dive into paper Magic, you can expect some subtle differences. If you shuffle up your deck and have to mulligan two or three games in a row, don’t worry! Nothing’s broken, that’s just how Magic works.



When you add all these things together–more games, different decks, sideboards and truly-random opening hands–what you get is variety. You get to play with and against a wider range of cards, and you more often have to navigate through games where one or both players decks aren’t cooperating with them. This variety is what makes Magic such a deep and challenging game with so much replay value.

It’s true that playing an individual game where you mulligan to five or miss your third land drop is not a particularly fun experience. This is part of the reason why playing BO1 on MTG Arena is such a great introduction to the game for newer players. However, it’s also true that having to prepare for those things – and sometimes battle back to a win after you have a bad start–makes Magic all the more rich and rewarding.

There’s nothing wrong with Best-of-One Magic. It’s fast and fun, and–like all formats–presents its own unique set of challenges to face and problems to solve. However, don’t be afraid to make the leap into Best-of-Three either, whether it means playing “traditional” on Arena or building decks with paper cards. Sideboards and random shuffling greatly increase the complexity of the game, and can be overwhelming at first. But soon you’ll begin to find the variety and the possibilities to be among the most fun aspects of Magic!

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