Three copies, or one?

A Built Deck is 52 cards, and every card except the Braincell is capped at three copies. Most decks give twenty of those slots to Braincells, which leaves about 32 for everything else, so three copies of one card is nearly a tenth of your real deck. My position: a card is worth three slots or worth one, and the cards that belong at three are the cheap, boring ones you'd be glad to draw twice in a row. The dramatic cards are singles. Build it the other way around and you've built a deck that loses with style.

Start with the math, because it's the whole argument. You open with seven cards and are dealt one at the start of each turn while you hold fewer than seven. A game that runs twenty turns shows you about 27 cards, roughly half the deck. One copy turns up in about half your games. Three copies means you nearly always see one and often two. Three copies is a promise: this card is how the deck wins, and a game without it is a game where the plan didn't show. One copy is the opposite promise: the deck works fine without this, and when it does arrive it's a gift.

Three slots go to the cards that never go stale

The question I ask of every card in the editor is simple. Would I be glad to draw a second copy while the first is still in my hand? If yes, three. If the second copy would sit there because the first already did the job, one. Almost no card survives that question at two.

Move Again is the clearest three in the catalog. One Braincell, one extra move this turn. There has never been a turn where a second move was worthless, and never a hand where a second Move Again was dead weight: the first makes a threat and the second makes the next one. First Blood runs three, and it's right to.

Flash Shield is the better example, because it gets stronger with each copy in a way the card text doesn't say. It's an Instant: you play it the moment your opponent lines up a capture, and the piece is protected until after your next turn. The first one saves a piece. The second one changes how your opponent plays, because once they've seen a Flash Shield they have to assume you hold another, and every capture they consider is a capture that might cost them a tempo. At three, they're right to worry for the entire game. That's a card whose third copy is doing work from inside your draw pile. Give it all three slots and don't look back.

One slot for anything that can only happen once

Now the other side. Purge removes every piece except the two kings. It costs five, it's the biggest thing you can do to a board, and you will play it exactly once, in the one position it's right for. A second Purge is a card with nothing left to purge. Running three of it isn't commitment, it's two dead draws dressed up as ambition. The same goes for anything that rewrites the whole game: Mill curses your opponent to lose if they ever end a turn with an empty draw pile, and one Mill is a threat for the whole game. The second is a threat they're already under.

The usual pushback is insurance: run two of the big card so you see it sooner. I don't buy it. A second copy raises your odds a little and hands you a dead draw whenever both show up. If a once-a-game card matters so much that you must see it, your deck is built on a surprise, and a deck built on a surprise has no plan in the half of its games where the surprise stays in the pile. Give that slot to a cheap repeatable, and let the big card stay what it's good at: the thing they didn't know you had.

So: threes are cheap and repeatable, singles are big and once. The one card the question doesn't fit is the Braincell, the only card with no cap, and how many of those to run is a tuning problem with its own article, The Braincell curve. Everything else is a one or a three. If you catch yourself writing a two, you haven't decided yet.