Side Decking Codified

Hey everyone! My name is Dru Knox and I’ve been playing Yu-Gi-Oh! competitively for about a year and a half. I want to talk today about what I think is the most important aspect of being a consistently top level player: side decking. I’ve been really happy to see a lot of articles about this important topic here on Alter Reality, but I feel like there’s still a lot of information to cover.

First, why is side decking the most important aspect of consistent top level play? To a lot of you reading, I’m sure the reasons are pretty clear. For one, even if you 2-0 almost all of your opponents, you still spend about half your duels with sided cards. Another reason siding is so important is that there’s no deck that has a perfect match-up against every other deck. And when you go to big tournaments, it’s possible to play against any deck type. So in order to do well in a big tournament, you have to have some way of handling the decks with which you have trouble.

When I sit down to build my side deck for a tournament, there’s a lot I do before thinking about which 15 cards to include. The first thing I do is analyze the possible decks I’ll be facing and categorize those match-ups as good, neutral, or bad. Some of this analysis is speculation based on future releases, but a lot of it can be done concretely by analyzing statistics from YCS’s and following feature matches. You can also play test with friends to get a better idea of what match-ups challenge your style of play.

Once I’ve got a comprehensive categorization of match-ups I plan on facing, I decide on what siding strategy to use against each deck. The side decking strategies I consider are match-up, transitional, and counter siding, and that’s what I want to spend the rest of this article discussing!

It’s important to point out that this level of analysis (and most of the theory in this article) is only really necessary for bigger tournaments. When you go to a smaller local tournament, you know who the good players are and you know what deck they’re running. In fact, you’ll probably only be facing 2-3 deck types, which means you have a lot of room to side very specific cards. For this scenario, I would recommend siding a lot of specific counters against the strongest opponents, and leave a few spots open for the less experienced players. Anyways, onto the interesting stuff!

Match-up Siding

Match-up siding can be separated into two main categories: general and mitigation. In general match-up siding, you’re preparing for a deck that you have about a 50% win rate or higher against (remember, you need to play at least 30 duels in order to have a win rate that’s actually statistically sound). Mitigation match-up siding is when you’re preparing for a deck that gives you a lot of trouble and you need to do some damage control.

For general siding, your main focus is taking out cards that are dead or subpar against your opponent’s deck. Obviously, you’ll want to replace those bad cards with some that are good in this match-up, but that’s strictly a secondary goal. You don’t want to waste valuable side deck space with hard counters that don’t hit any other decks. Your main deck already handles this match-up pretty well.

For that reason, you only want to side in 4-5 cards for a general match-up. You don’t want to break synergy by siding in too many off theme cards. In this scenario, it’s more important to keep your deck running smoothly while pulling out useless cards. You don’t even need to draw your sided cards; you just didn’t want to draw those dead cards you sided out.

Whereas general siding is all about getting bad cards out, mitigation siding is about getting good cards in. In this case, you may actually take out cards that aren’t dead in order to make room for strong counters to the opposing deck.

In mitigation siding, statistically speaking, you’re going to lose if you don’t see some of your sided cards. This means you should be siding 7-8 cards to give yourself a high probability of drawing one as soon as possible (8 cards in a 40 card deck gives a ratio of 1:5, meaning your 5 card opening hand should have 1 of those cards).

It’s important when preparing for a bad match-up to think about exactly how your deck is having trouble and side in cards that address that issue. If your deck can’t prevent huge amounts of early damage against Dino-Rabbit, don’t side in reactionary cards like Smashing Ground just because they’re a good way to force a negate from Laggia. Instead, side in defensive cards that prevent the early damage you were having so much trouble with. A good example of this is Agents, who only have 3 cards in the deck that can break up an attack. If you’re frequently getting OTK’ed playing Agents against Dino-Rabbit, side in Bottomless Trap Hole and Thunder King Rai-Oh to stop the deck before it can attack.

Transition Siding

Transition siding is where you side a huge portion of your deck’s engine out (8-15 cards) in order to change the way it plays. A lot of duelists like to adopt this kind of strategy for its surprise factor, but it’s very easy to miss the mark on the true goal of this method. You only want to employ a transitional side decking strategy when you know it will do one of two things: either it will leave your opponent with a large number of dead cards in their deck, or it will drastically increase the chance that they make an early game misplay.

With regards to dead cards, that’s fairly obvious. Either you have reason to suspect your opponents will all be siding in large numbers of cards against you, or your transition will leave tech choices in their main deck dead in the water.

Forcing misplays is a little more subtle. To make the point clear, I’ll take a totally artificial (and impossible) example. Let’s say you’re playing Plants vs. Karakuri, and somehow you’ve found a way to transition your deck into a pure T.G. build. This doesn’t really leave too many cards in your opponents deck dead (sided Debunks and D.D. crows will still be live), but it can bring about misplays. Expecting your spell heavy Plant build, they may push hard into Naturia Beast, which is a waste of resources and no longer hurts you, whereas Ally of Justice Catastor would have been a very strong threat with all of your big monsters being Earth.

The reason I stress that the misplays must be early game is that eventually your opponent will catch on, and if your strategy relies on them making a misplay in late game, it’s very likely they’ll have figured out your trick and won’t make the mistake.

Not every deck can support a transitional siding strategy. In general, you should consider transitional siding if your deck has a relatively well-defined engine and a large number of high utility cards. The reason for this is that you don’t want to diminish the value of all the cards in your deck when you pull out its engine.

As a practical example of all these facts being applied flawlessly, look at Chris Biswell’s 2nd place Plant deck at YCS Kansas City. The Plant engine is approximately 7 cards, and Biswell (like most Plant players) was running a bunch of high utility monsters like Tour Guide from the Underworld, Reborn Tengu, and Thunder King Rai-Oh. Furthermore, Plants is the dominant deck right now, so Biswell correctly anticipated Debunk, D.D. Crow, and Maxx “C” being sided in by all his opponents. His transitional siding strategy lead his opponents to have 7-8 dead cards. That’s a huge advantage right off the bat!

Counter Siding

The last major siding strategy is somewhere in between match-up and transitional siding, and is probably the most difficult to do well. Counter siding is anticipating what cards your opponent will side against you, and siding in cards to nullify those threats. I say that this is somewhere in between the other two side decking strategies because, sometimes, when looking for cards to replace those you took out for a general match-up, you’ll want to put in counter side cards. A good example of this was Six Samurai decks siding in Dimensional Fissure to nullify opponents’ Puppet Plants. Other times, like with Biswell, transitional siding is a great way to sidestep your opponent’s side deck threats altogether.

Either way, in order to counter side well, you need to know what decks have a bad match-up against yours (since they’ll be siding against you the hardest) and what cards your opponents are likely to use against you. The absolute best way to find this out is to look at the side decks from Top 32 deck lists of YCS’s. Look at what the best duelists are siding (odds are their decks will be net decked by everyone else), and try to figure out which of those cards would be used against you. Then, try to think how deadly those cards are, and if they’re a big threat, what cards you can use to counter them.

In general, if you’re running one of the most common decks in your meta, it’s also the most likely to be heavily sided against. People also tend to side against the most common decks in a very standard way, since there is a well-defined strategy established by the collective wisdom of everyone in the meta. This situation is the easiest to utilize counter siding in.

Counter siding is hard to do and can be extremely dangerous if done incorrectly. It requires a nearly perfect knowledge of the meta and a pretty strong read on how your opponent will be siding. If you draw your counter side card and your opponent doesn’t draw the card you meant to counter (or didn’t even side it in!), then your card will be dead. Because of this, you usually want to counter side with cards that have some general utility but are a direct counter to a huge threat to your deck (like Dimensional Fissure with Six Sams).


I thought I’d finish things up by showing how I apply the ideas in this article to a real life example: siding against Agents with Plants. Plants have a pretty solid match-up against agents. Depending on the build, my win rate game 1 is somewhere above 50%, suggesting a general match-up strategy.

My first step is to identify what cards need to come out. My 2 Mystical Space Typhoons and Heavy Storm are almost completely dead, so they’re coming out. One for One is also a risky card to leave in games 2 and 3 because there are so many ways it can become a minus if your opponent has sided aggressively.

On the topic of aggressive siding, Plants are dominating the meta right now, so I usually anticipate my opponent will be siding into 3 Maxx “C”, 1-2 D.D. Crow, and 1-2 Debunk. So for a general match-up side, I could pull out 2 MST, Heavy Storm, and One for One and replace them with 2 Bottomless Trap Hole and 1 Leeching the Light. The fourth card would be 1 Debunk to counter the hand traps my opponent was already running as well as the ones they’ve sided in.

As I mentioned above, I’m anticipating a lot of cards to be sided in against the Plant engine specifically. Another option, then, is a transitional siding strategy. In this case, I’d side out 1 Spore, 1 Lonefire Blossom, 1 Dandylion, 1 Debris Dragon, 1 One for One, 2 Mystical Space Typhoon, and 1 Heavy Storm. I’d replace those cards with 2 Fossil Dyna Pachycephalo, 1 Caius, 1 Leeching the Light, 2 Bottomless Trap Hole, 1 Dimensional Prison, and 1 Trap Dustshoot. I already main deck 3 Thunder King, which is why he isn’t being sided in.

Fossil Dyna shuts down most Agent plays, the extra Caius helps with Gachi Gachi Gantetsu, and the other cards are pretty self explanatory. By siding out my Plant engine, I also leave my opponent with 7-8 dead cards. Finally, notice that I only side 1 Leeching the Light. Because I have a pretty good match-up against Agents, I don’t waste side deck space with a bunch of hard counters, everything is very general.

Well, that’s all for now! If you guys liked this article, let me know in the comments. Until next time, it’s your move!


Roanoke, Virginia

Homestore: The End

Dru Knox

Dru Knox

Dru Knox

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