How to read a decklist you found online

Read the label before the cards

Find the format, the event or purpose, and when the list was played or updated.

For a physical TCG event, start with a list built for that event's format. TCG means Trading Card Game; OCG is the Official Card Game played in other regions. Their card releases and restrictions can differ. Master Duel has its own environment too. A list from another version of the game can give you ideas, but it needs a legality check before you bring it to your event.

Next, look at what the author says the list is for. A tournament result tells you where someone used it. A budget build tells you that cost influenced the choices. A combo demonstration may be built to show one particular play.

I'd rather learn from a current list with an explanation of its opening than an unexplained image carrying a huge “BEST DECK” label. Useful questions include “What do I do with an ordinary hand?” and “What happens if that first effect gets stopped?”

If the regional labels are the confusing part, check TCG versus OCG first.

Split the list into its three parts

Main Deck: 40–60 cards. This is the pile you draw from. A line marked “3 Shiranui Solitaire” means three copies in that section, and those copies all count toward its total.

Extra Deck: 0–15 cards. These start separately from the Main Deck. In Advanced, it can contain Fusion, Synchro, Xyz, and Link Monsters. Look for how the Main Deck reaches them: the materials, summoning effect, or other setup the play needs.

Side Deck: 0–15 cards. These are options for changing your deck between games of a match. You exchange cards one for one, keeping the deck sizes the same, then return to the original configuration for the next match.

So a list labeled “40 / 15 / 15” has a 40-card Main Deck, rather than 70 cards to shuffle together.

The usual three-copy maximum applies across all three sections combined, with tighter limits where the format requires them. Two copies in the Main Deck and one in the Side Deck already make three. For Genesys, points also count across the complete list, and Link and Pendulum Monsters are excluded.

Give the cards jobs

An online list may separate Monsters, Spells, and Traps. That's handy for counting, but a Spell and a monster can do the same job in your opening.

Start with these player terms:

• Starter: a card that begins the deck's main play. Check what else it needs before treating it as a one-card opening.
• Extender: a card that helps you keep playing once you've started, or recover when part of the play is stopped.
• Interaction: a card or effect that disrupts the opponent or answers something they've already put on the field.
• Payoff: what you're working toward, such as a monster that disrupts a play or pushes through enough damage to win.
• Engine requirement: a card another part of the strategy needs you to include, even when you would rather leave it in the Deck than draw it.

An engine is a group of cards that works together to carry out a plan. One card can have several jobs, and its job can change with your hand. These labels are a way to understand a list, rather than official card categories.

If a profile calls something a brick, it usually means a card that's awkward to draw or use by itself. Find out why it's there before cutting it. That awkward card may be the thing another card needs to fetch.

Follow one connection in the list

Suppose a teaching list includes three Shiranui Solitaire and one Uni-Zombie. The tempting conclusion is that Solitaire is important and Uni-Zombie is filler. Read their connection first.

Solitaire can Tribute a Zombie you control to Special Summon a Zombie Tuner with 0 DEF from your Deck. A Tuner is a monster used for Synchro Summons, and Uni-Zombie fits those requirements. Normal Summon Solitaire, activate its effect by Tributing itself, then bring out Uni-Zombie when that effect resolves. In that opening, Solitaire gets you to Uni-Zombie.

Three copies of the route. One copy of the destination. That's a possible reason for the different counts.

You still need to ask what happens if you draw the destination. With Uni-Zombie, you can Normal Summon it directly. Solitaire's Deck-summoning effect needs an eligible monster still in the Deck, so drawing your only Uni-Zombie changes that particular opening.

New to this? A Normal Summon uses your usual once-per-turn Normal Summon/Set. A Special Summon happens through a card effect or summoning method and doesn't spend that allowance. Here, Tributing Solitaire is the cost: it goes to the GY (Graveyard) before the effect resolves.

This is why I'd trace a starter into the card it reaches before deciding which names matter most. A single copy can be essential. Three copies can be there to help you see a useful opening more often.

Treat the ratios as clues

The quantities beside card names are often called ratios. Read them as decisions worth investigating.

Three copies can suggest the builder wants to draw that card often. One copy might be easy to find through another effect, needed only later, awkward in multiples, or limited by the rules. Two might be a compromise between access and drawing duplicates.

Those are possibilities, not the author's confirmed reasoning. A deck profile that explains the choice is much more useful than guessing from the number alone.

The same applies to a 41-card Main Deck. There may be a reason for the extra slot. Before you trim it to 40, check what leaves with it: a starter, a required target, or an answer the builder expected to need.

My take: keep the original ratios for your first attempt when you can. If you have to substitute a missing card, check that the replacement can do its job. “Another monster with the same Level” may leave you with a very different opening.

Read the Extra Deck as a route you can reach

A powerful-looking monster earns its slot when your deck can use it.

For each Extra Deck card in the demonstrated opening, find the step that puts it into play. Does the list produce the right materials? Does an earlier effect restrict what you can summon afterward? Is the card meant to finish your turn, clear an opposing card, or help reach something else?

Start with the route the author actually shows. You can learn the alternatives later.

Some Extra Deck cards also serve a purpose without being summoned, because another effect uses them as a resource. If you can't find the summon, look for that explanation before deciding the slot is wasted.

Ask what the Side Deck is trying to beat

A matchup means how your deck plays against a particular opposing strategy. Side Deck choices often tell you which matchups the builder expected.

For each card you want to bring in, ask what it answers and what you would take out. If you're adding three cards, you need three outgoing cards from the section you're changing. Keep enough of your own engine to execute the plan afterward.

I'd use the original Side Deck as a starting point, then choose changes based on the decks you actually face. A card included for one major event may have a very different job at your locals (local store tournaments).

You can learn this in small pieces. Understand one swap for a common opponent before trying to memorize every possible side-deck plan.

Make one buying decision, after one play makes sense

Check exact card names and current text in KONAMI's database. Artwork and rarity can change between printings; the effect you're buying the card for comes from its current text.

Now try the opening you've traced. Goldfishing means practicing your own plays without an opponent. Use it to learn where cards go and which resources the play spends, then try games with someone who can interrupt you.

You have enough understanding to start when you can explain the opening, identify its necessary pieces, and say what the deck is trying to achieve. Choose that plan before buying its missing cards. Build from your binder takes you through the next decision: the missing piece that makes a play possible, or another copy that helps you find it.