Traps, and how to play around them

A trap is the one kind of card your opponent plays and you don't get to see. Everything else in Built Deck lands face up and leaves a mark on the board: a frozen piece, a burning one, a shield. A trap lands face down. You know that something was placed, because you watched the card go down, and then you have to play chess on a board where one square, or one whole line, is lying to you.

This is how the traps work, how to lay them so they get stepped on, and how to walk across a board full of them without losing your queen to a hole in the ground.

The traps, one by one

There are three trap cards that take a square, sixteen that take a line, and one wall. They all need a hand, so they're all Built Deck cards.

Bear Traps are the sixteen: Bear Trap: a-file through Bear Trap: h-file, and Bear Trap: rank 1 through Bear Trap: rank 8. Each costs two Braincells and traps a whole file or rank. It goes face down into your actives pile, and the first enemy piece to land anywhere on that line is frozen for two turns. Your own pieces walk the line freely. Your opponent sees that you have a face-down active card; they don't see which line.

Spike Pit costs three and goes on one empty square. The first enemy piece to move onto it is destroyed. Kings step over it unharmed, which is the small mercy that stops a Spike Pit being a checkmate card.

Landmine also costs three and also takes an empty square, but it doesn't care whose piece arrives. The first piece to move onto it, yours or theirs, is destroyed. A king that steps on it loses the game. Yours included.

Claymore costs three and is the awkward one. It sits on a square and is aimed at a square beside it. The first piece to land on the aimed square dies, whoever owns it, and a king that lands there loses.

Wall isn't a trap in the sense of being hidden, but it comes from the same part of the catalog and does a related job. For three Braincells it builds a wall on an empty square. Pieces can't move onto it or slide through it; a rook's file ends where the wall starts. It crumbles after a few turns. Jump, for one Braincell, gives one of your kings or pawns the ability to step onto a wall square and break it, for the next few turns.

A piece destroyed by a trap is killed, not captured. That matters for anyone running resurrection: Instant Resurrection won't bring it back, and Revival will.

Laying a trap that gets stepped on

A trap nobody steps on is three Braincells spent on a square your opponent was never going to visit. The craft is in choosing squares your opponent has to visit, or wants to badly enough not to think.

Trap the recapture. Your opponent is about to take a piece. Where does their capturing piece end up? On the square your piece is standing on now. If that square is empty next turn because you moved away, a Spike Pit there is a trap on the exact square they've already decided to go to. It's hard to resist a free piece, and harder still when the free piece is still sitting there.

Trap the line their pieces live on. Bear Traps cover whole lines, and the best lines are the ones enemy pieces move along rather than across. A rook that's about to come to the open d-file will land somewhere on it, and Bear Trap: d-file catches it wherever it stops. The e- and d-files and the fourth and fifth ranks are where pieces go in the middlegame; the Hold the Line starter deck carries one Bear Trap for each of d, e and rank 4 for that reason.

Put a Landmine where a king wants to walk. A king castled on g1 has two squares it uses to escape pressure: h1 and h2, or f1 and the f2 pawn's square once that pawn has gone. A mine on one of them turns a safe-looking king walk into a lost game. Remember it's yours too: don't mine the square your own king will need.

Aim the Claymore at a square you can't mine. A Landmine needs an empty square. A Claymore sits on an empty square but kills on the one beside it, which can be occupied right now. Aim it at the square under an enemy knight, and the next piece to land there (the knight moving away doesn't trigger it, but whatever comes next does) is gone.

Lay it when they're busy. The best moment is a turn when your opponent has a forced recapture or a threatened king, and no spare attention for what you just placed face down.

Walking through a minefield

Now the other chair. Your opponent has just put a card down face down, and you have twenty squares to choose from.

Count what they've placed. Face-down active cards are visible as cards, if not as contents. One face-down active after a quiet turn is a Bear Trap on some line. A card that resolved onto the board and vanished was a trap on a square. You won't know which square, but you'll know a square is hot.

Ask what you'd trap. The squares above are the squares anyone would trap: the recapture square, the open file your rook obviously wants, the escape square by your king. If a capture looks free and you can't see why, the reason may be under the piece.

Move pieces you can afford to lose first. A pawn finds a Spike Pit for the price of a pawn. A queen finds it for the price of the game. When you must step onto a suspect line, step onto it with the least valuable piece that gets the job done, then follow with the valuable one once the line is known to be clear.

Make them trigger their own. Landmines and Claymores don't check whose piece arrives. If you can force an opponent's piece onto a square they mined, with a Move Opponent Piece or by giving check that leaves one escape, the trap works for you.

Or clear it. The vision role carries three answers at different prices. Probe costs one and clears whatever trap or wall is on the single square you point at; if you're wrong, the card is wasted, so it's for when you're sure. Disarm costs two and reveals and destroys every trap your opponent has placed, which also tells you how many there were. Wrecking Ball costs two and tears down every wall on the board. A face-down Bear Trap is an active card as well as a trap, so Dispel destroys it if it's your opponent's most recent active.

Don't freeze yourself into a corner. A Bear Trap freezes for two turns, which is long enough to lose a piece that's frozen on a square it was only passing through. Before a rook lands on a suspect file, ask whether you'd survive it standing still there for two turns under attack.

Walls, and the pieces that ignore them

A wall changes what the board is, briefly. Rooks and queens stop at it. Bishops' diagonals end at it. Pawns can't push through it. Nothing lands on it except a piece carrying Jump.

That makes a wall a tempo card as much as a defensive one. Dropped in front of an enemy rook on an open file, it buys the few turns it stands. Dropped on the square an enemy pawn would advance to, it holds that pawn in place while it stands. Dropped between your king and a checking line, it's a shield that costs no piece.

Jump is the counterpart. Giving your king the ability to step onto a wall and break it is a way out of a box; giving a pawn the same lets it keep marching. Jump is cheap and lasts a few turns, so it's worth holding in a deck that expects walls.

A deck that leans on traps

Traps are a role, and a deck can lean on them. Hold the Line, one of the five starter decks, is the template: shields and armor to make your pieces hard to take, walls to slow the attack, three Bear Traps and two Spike Pits to punish the pieces that come anyway, and Jump and Thaw to undo what your opponent does back to you.

The trap player's game is patient. You don't need to attack. You need your opponent to want to, and to be careless about where they put their feet.