A Yu-Gi-Oh! decklist is more than a pile of cards that work together. It contains three areas with different jobs: the Main Deck carries your starting game plan, the Extra Deck provides monsters accessed through specific Summoning mechanics, and the Side Deck lets you adjust between Games in a Match. Mixing these roles leads to incorrect counts, inaccessible options and changes that are difficult to reverse.
This method complements our guide to Yu-Gi-Oh! card legality in Europe. The purpose here is not to decide whether an OCG card is legal in the TCG. It is to build a readable list that can be tested, changed and restored reliably.
Give each Deck one clear responsibility
The Main Deck carries the opening plan
For official Constructed events, the Main Deck contains 40 to 60 cards. Side and Extra Deck cards do not count towards that total. The Main Deck should produce your normal openings, general interaction and follow-up resources without requiring one particular opposing strategy.
Sort cards temporarily by function: starters, extenders, interaction, defensive tools and follow-up. This is more informative than separating only Monsters, Spells and Traps. A Monster may primarily be a starter, so its strategic role matters more than its card frame when you assess consistency.
The Extra Deck contains accessible Summoning options
The Extra Deck may contain up to 15 Fusion, Synchro, Xyz or Link Monsters. These cards never belong in the Main Deck. Do not treat all 15 slots as a gallery of powerful cards. Every monster should have a realistic route using the Levels, Types, Attributes, materials or Link arrows available to your strategy.
Divide it into three groups: pieces required by the main combo, recovery options when the first route is stopped, and answers for specific board states. If you cannot describe how a card is Summoned during a normal sequence, that slot is probably not supporting the decklist.
The Side Deck changes a Match between Games
A tournament Side Deck contains 0 to 15 cards. Between Games, cards may be exchanged with the Main or Extra Deck on a one-for-one basis. The confirmed sizes must remain unchanged after siding, and the original Main and Extra Deck configuration must be restored after the round.
Each Side Deck choice needs a defined purpose: graveyard strategies, heavy Spell and Trap line-ups, difficult established boards, or a need to play first or second. Record the card leaving the list next to the card entering it. This prevents an accidental change to your Main Deck size.
Control table for all three lists
| Area | Official size | Control question | Common mistake |
|---|---|---|---|
| Main Deck | 40 to 60 cards | Does the core plan work without a specific opponent? | Adding answers until starters become too diluted |
| Extra Deck | Up to 15 cards | Does every monster have a realistic Summoning route? | Including a strong but inaccessible card |
| Side Deck | 0 to 15 cards | What leaves for every card that enters? | Changing the size of the Main or Extra Deck |
Build the decklist in six steps
- Describe the deck in one sentence. State how it builds a board, disrupts the opponent or generates resources.
- Fix the Main Deck core. Start with required engine cards, then add consistency and general interaction.
- Connect every Extra Deck card to a sequence. Write down the materials and steps needed to Summon it.
- Define Side Deck scenarios. Give every card a matchup and note whether it is intended for going first, second or both.
- Prepare equal swaps. Record entries and exits in equal quantities and check limits across all three Decks.
- Test and restore. Return to the original configuration after every session so results remain comparable.
Check card limits across the complete list
The general rule allows no more than three copies of one card across the Main, Extra and Side Deck combined. The current Forbidden and Limited List can reduce that number. Forbidden cards cannot appear in any of the three lists, while Limited and Semi-Limited cards are counted across all three together. Always check the list that applies to your region before an event.
Keep a dated decklist with separate Main, Extra and Side columns. Add an automatic total for each card. This simple layout reveals an accidental fourth copy split between two areas and makes post-testing changes easier to track.
Prepare the physical deck
Keep the Extra and Side Deck visibly separate from the Main Deck. A deck box made for sleeved cards helps preserve a stable order. Neutral dividers can separate groups, while the siding plan should remain in an external note rather than among playable cards.
Before leaving, count all three areas, check sleeve requirements and remove cards from recent trades. Cards not registered on the decklist should not remain with the playing deck, except clearly identified Tokens.
Pre-round checklist
- Main Deck restored to its original size and contents;
- Extra Deck complete and separated;
- Side Deck counted and matched to the list;
- combined copy limits checked across all three areas;
- regional Forbidden and Limited List reviewed;
- no unrelated card left in the deck box.
Good organisation does not automatically make a deck stronger, but it makes decisions clearer and testing more useful. You know why every card is present, where it belongs and what will replace it.
Ready to clarify your decklist? Prepare the three lists separately, then check their consistency before your next game.