Over this past weekend, there were Regional tournaments held all across the country. I attended the Regional in Butler and made the Top 4 there. Throughout the day, I noticed one key difference between those players who were successful in their duels and those who weren’t. It wasn’t what deck type they played, it wasn’t how they were topdecking, and it wasn’t that their opponents were bad players. The main trait that set the successful duelists apart from the rest was their strategic use of the side deck.

Since the Advanced format began, players have been trying to figure out what decks will be the next big thing. This doesn’t just include figuring out how to play and win with a new type of deck; it also involves learning how to play against and beat the deck. Since the discovery that Burn decks are now tier one, everyone has had an eye on certain cards in the hopes of using them for easy wins against burn players. The problem is that you want to play as close to 40 cards as possible, but you also want to make sure you have an answer to certain deck types. These answers aren’t always the same for different deck types, and as a result, some cards become dead weight in many matchups. The solution to this problem is the side deck—those fifteen cards you just can’t bring yourself to put in your main deck that can be the ace up your sleeve in a difficult matchup. What makes a successful side deck? What is the proper way to use the side deck? These are the topics I would like to cover today.

The first thing we need to know before we can use our side deck is what to put in it. Keep the following points in mind as you look to construct your own side deck.

What are the inherent weaknesses of your deck type?

Is Kinetic Soldier getting you down? Does Creature Swap usually end the game for you? Do you find yourself often getting stuck with Lava Golem on your side of the field? Is there anything that you don’t want to see your opponent play? If you answered yes to any of these questions, then your deck has an inherent weakness.

One of the primary purposes of using your side deck is to plug up the gaps in your strategy that your opponent could find. If your deck rolls over and dies to Jinzo, Mobius The Frost Monarch, or Lava Golem, you may want to consider playing a couple copies of Mask of Restrict in your side deck. If you’re running a deck that wants to make sure your monsters stay on your side of the field, may I suggest a copy or two of Remove Brainwashing? The first thing that a good side deck can do is to allow you to switch your deck to a form that minimizes or eliminates its weaknesses against another type of deck.

Are there any cards that you would really like to have in your deck, but are too situational to be useful a majority of the time?

Are you concerned that you might need extra spell or trap removal, but afraid that it will never come in handy? Put it in your side deck. Are you afraid that Book of Moon and Offerings to the Doomed are going to be heavily played but unsure if it will be enough to justify a main deck Invader of Darkness? Put it in your side deck. It can be hard to cut your deck down to a reasonable size, but it gets easier if you remember that anything you feel you might need can have a spot in the side deck.

Are there any cards that could give you a quick, surprising advantage over your opponent in a tight spot?

There are a lot of excellent spell and trap cards out there that have never seen any real tournament use. Examples of these would be Magical Hats or, my personal favorite, Mirror Wall. If you spring Mirror Wall on your opponent when you’re in a tight spot, it might be able to turn the tide of the duel back in your favor. Of course, it’s also a lot of fun for the spectators when they see a card that’s rarely played hit the field and win the game.

Now that we know what kind of cards should have a place in our side deck, how should we decide what comes out of our deck when we want to put them in? It’s important to remember that you must always side in cards on a one-for-one basis, and it’s equally important to realize that you are trading one of your deck’s capabilities for another. “Scripting” your side decking is a technique that I find particularly effective. What I mean by scripting is to decide ahead of time what cards you will side in or out when you face a specific situation.

Whenever I come up against another Warrior deck, I side out one Goblin Attack Force and one Marauding Captain for two copies of Kinetic Soldier. I remove my Nobleman of Crossout for a second Creature Swap, and I remove Morphing Jar for Mirror Wall. I make these changes because I’ve found through testing that Kinetic Soldier, Creature Swap, and Mirror Wall are the cards that will usually win me a mirror match against another Warrior deck. Nobleman of Crossout, small monsters, monsters that switch to defense mode after attacking, and cards that let both players draw are a huge disadvantage when I’m playing against another deck like my own. The key here is to do your homework ahead of time, so that when it’s time to use the side deck, you don’t hesitate or make bad decisions that could cost you a match.

That’s not to say that you have to make all your changes in advance. Sometimes you have to improvise because a card just isn’t going to do you any good in a certain match. You may realize in the middle of the game that a card in your side deck would be absolutely killer against the person you’re playing. A good example of this would be a friend of mine who was running a deck depletion deck at the Butler Regional. In the first round, he was paired against a newer player with a 125-card deck. Obviously, there’s almost no way for someone with a 125-card deck to run out of cards, so he lost game 1. He had the proper cards in his side deck to beat his opponent in the next two games, but he failed to realize it until after he had lost the match. This is the kind of situation that you don’t want to find yourself in due to failing to use your side deck effectively.

There you have it—a good look at the science behind the side deck. Next time you go to fill out your deck list, remember that the fifteen cards you put down in the side deck space may be the difference between qualifying for Nationals and going 0-2, drop in the tournament. Until next time, play hard, play fair, and most importantly, have fun!