Hello my fellow Planeswalkers! I am The MTG Hero and today we will be breaking down the most important part of competitive play, sideboarding. When I was just starting tournament grinding many years ago, I was told “sideboarding is the most important part of deck building because you only play one game with your maindeck. You play up to two with your sideboarded deck.” This has stuck with me and as a result, I work harder on my sideboards than anything else. I have spent hours upon hours writing down my own guides and tweaking.
What a Sideboard Is and Is Not
For many players, deckbuilding ends at 60 cards. The sideboard is often an afterthought. Generally just thought of as “fifteen cards thrown together to deal with stuff.” But at competitive and semi-competitive levels of Magic, a strong sideboard doesn’t just patch weaknesses; it completely reshapes matchups,
At its core, a sideboard exists to modify your main deck after Game 1. It is not:
A pile of silver bullets for every possible deck
A place for cards that “almost made the cut”
A backup deck you wish you were playing
Instead, your sideboard should be a targeted extension of your main deck’s plan. Every card should have a clear purpose and a clear matchup it improves.
A good rule of thumb is: If you can’t name the matchup and the card you’re cutting for it, the sideboard card doesn’t belong.
Identify Your Deck’s Core Game Plan
Before choosing sideboard cards, you need to understand what your deck is trying to do better than other decks.
Ask yourself:
Am I proactive? This is aggro, combo and other linear synergies.
Am I reactive? This is control, midrange.
Do I win by speed, inevitability, or disruption?
Your sideboard should support your deck’s identity, not fight it.
Example:
If you’re an aggressive deck, your sideboard cards should usually:
Remove blockers efficiently
Protect your threats
Disrupt opposing stabilization tools
Identifying your decks weaknesses helps decide what you need. I suggest starting by being honest about what your maindeck cannot beat. Put your ego aside, no deck is perfect.
Ask yourself:
What decks am I unfavored against?
What cards or strategies give me the most trouble?
Do I lose to speed, inevitability, interaction, or specific hate cards?
Example:
Aggro decks often struggle against sweepers and lifegain.
Combo decks can fold to disruption or hate permanents.
Midrange decks may have trouble closing games against control.
Map the Metagame
You don’t need to beat every deck. You need to beat the decks you’re most likely to face.
Break the metagame into categories:
Aggro
Midrange
Control
Combo
Graveyard-based decks
Artifact/enchantment decks
Then ask:
Which matchups are already good?
Which are close?
Which are actively bad?
Your sideboard should generally prioritize bad and close matchups. Some people say that there are matchups so bad that you shouldn’t even try to board for, but I don’t like this. I will generally have just what I need to have a chance and that’s it. I won’t over board for it, but I won’t ignore it.
In that same camp, people say matchups are so good that you don’t need a plan for and that is definitely true. But I will still have one or two slots for cards to lock the matchup up.
A sideboard should be built for expected opponents, not theoretical ones. Just because a person at your shop plays some weird deck you need specific cards to beat, doesn’t mean you will see that deck at every event, so you probably shouldn’t board for it at a bigger event or a different store.
You don’t need a silver bullet for everything, but you do need meaningful plans against the decks you expect to play multiple times in an event.
A good rule of thumb:
60–70% of your sideboard should target your worst or most common matchups
The remaining slots can be flexible or high-impact hate cards
Choose Flexible Cards Over Narrow Ones When Possible
Cards that serve multiple purposes are sideboard all-stars and I am constantly looking for these to make building my deck easier.
For example:
A removal spell that also exiles helps against both aggro and graveyard decks.
A threat that removes enchantments and creatures can be good against aggro and control decks
A strong planeswalker can help you go over the top of opposing aggro decks and threaten control/midrange decks
Narrow hate cards are still important, but every slot you dedicate to a single matchup is a slot you’re not using elsewhere. Ask whether a card improves several matchups or dramatically improves one critical matchup.
Choose Sideboard Roles
Most strong sideboards include cards that fall into a few key roles like interaction you don’t want main deck.
These are answers that are powerful but narrow.
Graveyard hate
Artifact/enchantment removal
Combo disruption
They’re too situational for Game 1, but devastating when relevant. These cards change how your deck plays post-board.
Additional threats against control
Sweepers against creature decks
Card advantage engines for grindy games
This is where you surprise opponents who sideboard incorrectly.
Protection spells are cards that defend your main plan:
Anti-removal effects
Countermagic
Taxing effects
These are especially important for linear decks that rely on a small number of key pieces.
Getting the Numbers Right
A common mistake is running too many single copies: “This card is good against that deck, so I’ll play one” multiple times
In practice, a bunch of one-ofs are unreliable unless you have card selection or tutoring. Sideboard cards should appear often enough to matter.
General guideline for building your sideboard and even your main deck is:
1 copy: Tech
2 copies: You want to have it, but it isn’t life or death
3 copies: Cards you want to see
4 copies: Cards you must have
Plan Your Cuts Before the Event
The most common mistake I see is players not considering that sideboarding isn’t just about what comes in, it’s about what comes out as well.
For every matchup, you should know:
Which cards get worse post-board
Which cards are actively bad
How many slots you realistically have
Writing this down or testing it beforehand prevents panic sideboarding and overboarding.
A common mistake is boarding in too many cards and weakening your deck’s core.
If you bring in 6 cards, make sure you actually have 6 cards to cut. This also works in reverse, if you have 6 cards that are actively bad or unplayable in a matchup, make sure you have 6 good cards to bring in. Not just random crap.
More cards in does not automatically mean better.
As a guideline:
Most matchups involve 3–6 cards coming in.
Extreme matchups might involve 7–9, but those are rare.
If you’re swapping half your deck every round, something is wrong.
Test, Adjust, Repeat
A sideboard is never “finished” metas are constantly evolving and changing. No two tournaments are the same. Your local meta might be full of aggro decks, but going to a RCQ or bigger events you might see considerably more midrange, control and combo. Know the room and what to expect.
Basically, after matches, ask yourself:
Did I draw my sideboard cards?
Did they actually improve the matchup?
Was there a card I always boarded in but never wanted to draw?
The best sideboards evolve with:
The metagame
Your playstyle
Your deck’s tuning
Be willing to cut “theoretical” cards for ones that perform in real games.
Sideboarding is matchup dependent. A card that’s excellent in one matchup may be terrible in another.
Ask:
Which of my cards line up poorly against my opponent’s plan?
Which cards are slow, low-impact, or easily answered?
For example:
Creature removal against spell-based combo
Expensive threats against hyper-aggressive decks
Narrow interaction against redundant strategies
The goal is not to remove “bad cards” universally, but bad cards in this matchup.
Wrap-Up
A strong sideboard is intentional, disciplined, and focused. It doesn’t try to do everything. But what it does, it should do well. When built correctly, your sideboard becomes a weapon, not a safety net. If Game 1 shows you how the matchup starts, the sideboard determines how it ends. Build it with the same care you give your main deck, and you’ll win matches before the second game even begins.
I hope this guide into my deck building helps! As always I would love to hear feedback from my readers and it helps me grow not just as a content creator, but as a player. I always listen for good advice or something I can take away from a conversation and apply to my own play. That is how I have become successful in this game and I hope others do the same. Until next time Planeswalkers, Hero out!
Links
If you enjoy the content please consider following me at the links below because your support and interaction inspires me to keep doing what I love which is bringing you the best MTG content I can!
youtube.com/themtghero
twitch.tv/themtghero
patreon.com/themtghero
x.com/themtghero