Paying with pieces

Most cards cost Braincells and nothing else. A few want more, and they show it on the card's edge as icons under the cost: a card for cards discarded from your hand, a skull for one of your own pieces sacrificed, a gift for a captured piece handed back to your opponent. You pay all of it when you play the card, and you can't play the card without it.

These are the cards that charge in pieces, cards and favors, and the way to think about whether the price is right.

The three currencies

Discards come out of your hand. Some cards let you choose which; others take them at random. Either way, each one is a card you won't get to play, and your hand gets back one card a turn at most.

Sacrifices are your own non-king pieces, chosen by you, removed from the board. The piece doesn't fall to an enemy; it's gone because you spent it.

Give-backs return a piece you captured to your opponent. The piece they get is their most recently captured, so you know in advance what you'd be handing over. If it was a pawn, it's a cheap favor. If it was their queen, the card had better be worth a queen.

Each currency has a different exchange rate, and it changes through the game.

The cards that take a piece

Blood Oath costs one Braincell and one piece, for two extra moves this turn. Sacrificing a pawn that was in your own way is nearly free, and two moves for a Braincell and a pawn is the best rate on tempo in the game. Sacrificing a rook for it is a different card.

Trade Up costs two Braincells and a piece, and resurrects your most recently captured piece where it fell. The name is the instruction: give up something small to get back something big. You lost a queen last turn, you still have a pawn you don't need, and for two Braincells the queen is back on the square it died on. If the piece you lost last was a pawn, the card does nothing worth doing.

Salvage costs two Braincells and a piece, and takes the top card of your discard pile into your hand. A piece for a card is the exchange rate here, so it's for when the card on top of your discard is worth a piece: the Countermand you had to spend, the Lightning Strike you played last turn.

All In takes all three currencies at once (a card, a piece, a give-back) plus two Braincells, for three extra moves. The cheapest version is a worthless card, a doomed pawn and a captured pawn handed back; the most expensive is your last good card, a rook and their queen. The card is the same. What you pay depends entirely on when you play it.

The cards that take cards

Fire Sale costs one Braincell and two other cards from your hand, your choice, to destroy an enemy piece outright. Destroying a queen for one Braincell and two cards you weren't going to play is a trade any attacker takes. Two cards from a hand of three is a different matter: you've emptied your hand for the piece, and a Mind Blank curse would end the game on the spot.

Blood Pact costs two Braincells and two cards at random, and resurrects your most recently captured piece where it fell. The random discard is the risk, and the way to manage it is to play Blood Pact when your hand is full of cards you're indifferent to, not when it holds the one Instant you've been saving.

Barter costs two Braincells and two random cards, and takes any card of your choice from your discard pile into your hand. Two random cards for the one you want is fair when the one you want is the right card for the position and the two you lose are not.

Hostile Takeover doesn't charge in cards, but it leaves you with more than you can hold: you take your opponent's whole hand, and have to discard down to the hand limit before you can end the turn. Think of it as the opposite price. You're paying in the cards you can't keep.

The cards that give a piece back

Ransom costs one Braincell and returns your opponent's most recently captured piece to the board, in exchange for three Braincells. Net two Braincells up, and a piece your opponent gets back. When the piece is a pawn, Ransom is one of the best economy cards in the game. When it's a knight they'll put straight back into the attack, it's handing them a knight for two Braincells.

Prisoner Exchange costs two and the same give-back, for an extra move this turn. A move for a piece: good when the move is decisive and the piece is small.

Hostage Swap costs one Braincell and a give-back, and runs the other way round. Your opponent brings back a captured piece of their choice; you get your most recently captured piece back. You're trading the best piece they've lost for the last piece you lost. It's right when you've just lost your queen and they've lost nothing but pawns, and wrong in almost every other position.

Necromancy is the Ransom of the killed. For two Braincells and a give-back it raises your opponent's most recently killed piece (killed by a Lightning Strike, an Assassinate, a trap) back to life on their side, and pays you three Braincells. The piece has to have been killed, not captured; the two piles are different, and Revival and Necromancy read the killed one.

Pricing a piece

The usual chess values (pawn one, knight and bishop three, rook five, queen nine) are a fine start, but three things move them in Built Deck.

What's left matters more than what it's worth. A pawn when you have eight is cheap. A pawn when it's your last piece in front of the king is not. Sacrifice from the pieces you have the most of.

What it's doing matters. A knight stuck on the rim is worth less than its three points, and makes a better sacrifice than a knight in the center. Blocked pawns, trapped bishops and rooks with no file are the pieces to pay with.

Whether it comes back matters most of all. In a deck with Instant Resurrection and Initial Resurrection, a sacrificed piece isn't gone. Second Life, the starter deck built around exactly this, trades pieces freely because the resurrection cards keep bringing them home. In a deck with no regain cards at all, every sacrifice is permanent and the price is the whole piece.

Pricing a card

A card's value is what it would do if you played it, which depends on the position. A Flash Shield is worth nothing in a position where nothing's threatened and a piece when something is. Discard the cards whose moment has passed or isn't coming: the Thaw when nothing of yours is frozen, the Douse when nothing's burning.

The random discards (Blood Pact, Barter) can't be steered, so they want a hand of roughly equal cards. Play them when the hand is full of Braincells and middling cards, not when it's two Braincells and a Countermand.

Pricing a favor

A give-back is the hardest to price because the value is set by your opponent. The piece goes back to them, and what it's worth is what they'll do with it. A returned pawn is a tempo for them at most. A returned rook is an attacker. A returned queen can be the game.

The rule of thumb: play give-back cards right after capturing something small. You choose when to play Ransom; choose the turn after you took a pawn.

The sum

Every one of these cards is a bargain in one position and a blunder in another, and the card itself doesn't change. What changes is what you have left, what your hand holds, and what your opponent has lost most recently. Before paying in anything other than Braincells, look at those three, and ask whether the thing you're paying with is something you'd miss.